Word Definition
absorptiometer instrument for measuring solubility of gases in liquids
accelerometer instrument for measuring acceleration or vibrations
acetimeter instrument for measuring strength of vinegar
acidimeter instrument for measuring concentration of acids
actinograph instrument used to calculate time of photographic exposure
actinometer instrument for measuring incident radiation
aerometer instrument for measuring weight or density of gas
aethrioscope instrument for measuring temperature variations due to sky conditions
alcoholometer instrument for measuring proportion of alcohol in solutions
alcovinometer instrument to measure strength of wine
algometer instrument for measuring sensitivity to pain
alkalimeter instrument for measuring strength of alkalines
altimeter instrument for measuring altitude
ammeter instrument for measuring electrical current
anemograph instrument for measuring pressure and velocity of wind
anemometer instrument for measuring wind velocity
areometer instrument used for measuring specific gravity
arthroscope instrument for examining interior of a joint
atmometer instrument for measuring evaporating capacity of air
audiometer instrument for measuring acuity of hearing
auriscope instrument for examining the ear
auxanometer instrument for measuring growth of plants
auxometer instrument for measuring magnifying power
ballistocardiograph instrument for detecting body movements caused by heartbeat
barograph instrument for recording air pressure
barometer instrument for measuring air pressure
baroscope weather-glass
bathymeter instrument for recording contours of deep oceans
bathythermograph instrument for recording water temperature as compared to depth
bolometer instrument for measuring radiant energy or infrared light
bronchoscope instrument for examining the windpipe
calorimeter instrument for measuring absorbed or evolved heat
cardiograph instrument for recording movements of the heart
cathetometer instrument for measuring short vertical distances
ceilometer instrument for measuring height of cloud ceiling above earth
ceraunograph instrument for recording thunder and lightning
chlorometer instrument for measuring amount of chlorine in a solution
chromatograph instrument for performing chromatographic separations
chromatoptometer instrument measuring eyes' sensitivity to colour
chronograph instrument for recording the moment of an event
chronometer instrument for measuring time
chronoscope instrument for measuring very short time intervals
clinometer instrument used to measure slopes and elevations
coercimeter instrument for measuring coercive force
colonoscope instrument for viewing the colon
colorimeter instrument for measuring and determining color
colposcope instrument for viewing the neck of the uterus
coronagraph instrument for viewing the corona of the sun
coulombmeter instrument for measuring electric charge
coulometer instrument measuring amount of substance released in electrolysis
craniometer instrument for measuring the skull
cratometer instrument for measuring power of magnification
crescograph instrument for measuring the growth of plants
cryometer instrument for measuring low temperatures
cryoscope instrument for determining freezing points of substances
cyanometer instrument for measuring blueness of the sky or ocean
cyclograph instrument for describing arcs of circles without compasses
cyclometer instrument for measuring revolutions of a wheel
cymograph instrument for tracing the outline of mouldings
cymometer instrument for measuring frequency of electrical waves
cystoscope instrument for examining the bladder
cytometer instrument for counting cells
decelerometer instrument for measuring deceleration
declinometer instrument for measuring magnetic declination
dendrometer instrument for measuring trees
densimeter instrument for measuring closeness of grain of a substance
densitometer instrument for measuring optical or photographic density
diagometer instrument for measuring electrical conductivity
diagraph instrument for enlarging or projecting drawings
diaphanometer instrument for measuring the transparency of air
dichroscope instrument for examining crystals for dichroism
diffractometer instrument for determining structure of crystal through light diffraction
dilatometer instrument for measuring expansion
dioptometer instrument for measuring focus or refraction of the eyes
dipleidoscope instrument for measuring moment when an object passes a meridian
diplograph instrument for writing two lines of text at once
dosimeter instrument for measuring dose of radiation
dromometer instrument for measuring speed
drosometer instrument for measuring dew
durometer instrument for measuring hardness of substances
dynamograph instrument for recording mechanical forces
dynamometer instrument for measuring mechanical force
ebullioscope instrument for measuring boiling point of liquids
effusiometer instrument for comparing molecular weights of gases
eidograph instrument for copying drawings
elatrometer instrument for measuring gaseous pressure
electrocardiograph instrument for recording unusual electrical fluctuations of the heart
electrodynamometer instrument for measuring electrical current
electroencephalograph instrument for measuring the brain's electrical impulses
electrograph instrument for recording electrical potential
electrometer instrument for measuring electrical potential
electromyograph instrument for diagnosing neuromuscular disorders
electroretinograph instrument for measuring electrical activity in the retina
electroscope instrument for detecting electrical charges in the body
ellipsograph instrument for describing ellipses
encephalograph instrument for recording brain images
endoscope instrument for visualizing interior of a hollow organ
endosmometer instrument for measuring osmosis into a solution
epidiascope instrument for projecting images of objects
episcope instrument for projecting images of opaque objects
ergograph instrument for measuring and recording muscular work
ergometer instrument for measuring work performed
eriometer instrument for measuring very small diameters
eudiometer instrument for measuring air purity
evaporimeter instrument for measuring rate of evaporation
extensometer instrument for measuring deformation in object due to forces applied
fathometer instrument for measuring underwater depth using sound
fiberscope instrument using fiberoptics to examine inaccessible areas
floriscope instrument for inspecting flowers
flowmeter instrument for measuring properties of flowing liquids
fluorimeter instrument for measuring fluorescence
fluoroscope instrument using x-rays to examine internal structure of opaque object
focimeter instrument for measuring focal length of a lens
galactometer instrument for measuring specific gravity of milk
galvanometer instrument for measuring electrical current
galvanoscope instrument for detecting presence and direction of electric current
gasometer instrument for holding and measuring gases
gastroscope instrument for examining interior of the stomach
geothermometer instrument for measuring subterranean temperatures
goniometer instrument for measuring angles between faces
gradiometer instrument for measuring gradient of a physical quantity
gravimeter instrument for measuring variations in gravitational fields
gyrograph instrument for counting a wheel's revolutions
haptometer instrument measuring sensitivity to touch
harmonograph instrument drawing curves representing vibrations
harmonometer instrument measuring harmonic relations of sounds
helicograph instrument for drawing spirals on a plane
heliograph instrument for measuring intensity of sunlight
heliometer instrument for measuring apparent diameter of the sun
helioscope instrument for observing sun without injury to the eyes
hemacytometer instrument for counting blood cells
hippometer instrument to measure height of horses
hodoscope instrument for tracing paths of ionizing particles
hydrometer instrument for measuring specific gravity of liquids
hydroscope instrument for viewing under water
hydrotimeter instrument for measuring water hardness
hyetograph instrument for recording rainfall
hyetometer instrument for measuring rainfall
hyetometrograph instrument for recording rainfall
hygrograph instrument for recording variations in atmospheric humidity
hygrometer instrument for measuring air moisture
hygroscope instrument for displaying changes in air humidity
hypsometer instrument for measuring height of trees through triangulation
iconometer instrument for finding size of object by measuring its image
idiometer instrument for measuring motion of observer in relation to transit of the heavens
inclinometer instrument for measuring inclination to the horizontal of an axis
interferometer instrument for analysing spectra of light
iriscope instrument for exhibiting the prismatic colours
katathermometer instrument for measuring the cooling power of air
katharometer instrument measuring changes in composition of gases
keratometer instrument for measuring curvature of the cornea
keraunograph instrument for recording distant thunderstorms
kinetoscope instrument for producing curves by combination of circular movements
konimeter instrument measuring amount of dust in air
koniscope instrument for measuring dust in air
kymograph instrument for recording fluid pressure
labidometer instrument for measuring size of the head of a fetus
lactometer instrument for testing relative density of milk
lactoscope instrument for measuring purity or richness of milk
lanameter instrument for measuring quality of wool
laparoscope instrument for viewing interior of peritoneal cavity
laryngoscope instrument for examining interior of the larynx
leptometer instrument for measuring oil viscosity
loxodograph device used to record ship's travels
lucimeter instrument for measuring light intensity
luxmeter instrument for measuring illumination
lysimeter instrument for measuring percolation of water through soil
magnetograph instrument for recording measurements of magnetic fields
magnetometer instrument for measuring intensity of magnetic fields
manometer instrument for measuring pressure of a liquid or gas
marigraph instrument for recording tide levels
mecometer instrument for measuring length
megameter instrument for determining longitude by observing stars
megascope instrument for projecting an enlarged image
mekometer range-finder
meldometer instrument for measuring melting points of substances
meteorograph instrument recording a variety of meteorological observations
methanometer instrument for detecting presence of methane
microbarograph instrument for recording minute changes in atmospheric pressure
microcalorimeter instrument for measuring tiny quantities of heat
micrograph instrument used to write on a very small scale
micrometer instrument for measuring very small distances
micronometer instrument for measuring short periods of time
microscope instrument for magnifying small objects
microseismograph instrument for recording small or distant earthquakes
microseismometer instrument for measuring small or distant earthquakes
mileometer instrument for recording distance travelled in miles
milliammeter instrument for recording very small electrical currents
myograph instrument for recording muscular contractions
myringoscope instrument for viewing the eardrum
nephelometer instrument for measuring cloudiness
nephograph instrument for photographing clouds
nephoscope instrument for observing direction and velocity of clouds
nitrometer instrument for measuring nitrogen and its compounds
odograph odometer; instrument for measuring distance travelled
odometer instrument for measuring distance travelled
odontograph instrument for obtaining curves for gear-teeth
oenometer instrument for measuring alcoholic strength of wine
ohmmeter instrument for measuring electrical resistance
oleometer instrument for measuring amount of oil in a substance
olfactometer instrument measuring intensity of odour of a substance
ombrometer rain-gauge
oncometer instrument measuring change in size of internal organs
oncosimeter instrument measuring variations in density of molten metal
ondograph instrument measuring change in wave formations of electricity
oometer instrument for measuring eggs
opacimeter instrument for measuring opacity
opeidoscope instrument for illustrating sound by means of light
ophthalmometer instrument for measuring the eye
ophthalmoscope instrument for viewing the interior of the eye
opisometer instrument for measuring curved lines
opsiometer instrument for testing vision
optometer instrument for testing vision
orchidometer instrument for measuring the size of the testicles
oscillograph instrument for recording alternating current wave forms
oscillometer instrument for measuring ship's rollings
oscilloscope instrument for detecting electrical fluctuations
osmometer instrument for measuring osmotic pressure
otoscope instrument for examining the ear
pachymeter instrument for measuring small thicknesses
pallograph instrument measuring ship's vibration
pantochronometer combined sundial and compass
pantograph instrument for copying drawing to a different scale
passimeter instrument for issuing automatic tickets
pedometer instrument for measuring distance travelled on foot
peirameter instrument measuring resistance of road surfaces to wheel movement
pelvimeter instrument for measuring the pelvis
penetrometer instrument for measuring firmness or consistency of substances
permeameter instrument for measuring permeability
phacometer instrument for measuring lenses
phaometer old instrument for measuring light intensity
pharmacometer instrument for measuring drugs
pharyngoscope instrument for inspecting the pharynx
phonautograph instrument for recording sound vibrations
phonendoscope device which amplifies small sounds
phonometer instrument for measuring sound levels
phorometer instrument used to correct abnormalities in eye muscles
photometer instrument for measuring light intensity
photopolarimeter instrument for measuring intensity and polarization of reflected light
phototachometer instrument for measuring the speed of light
phototelegraph instrument for transmitting drawings telegraphically
phthongometer instrument measuring intensity of vowel sounds
piezometer instrument for measuring pressure or compressibility
pitchometer instrument for measuring angles of ship's propeller blades
planigraph instrument for copying drawings at a different scale
planimeter instrument for measuring area of plane figures
platometer instrument for measuring area; planimeter
plegometer instrument for measuring the strength of a blow
plemyrameter instrument for measuring variations in water level
plethysmograph instrument for measuring change in body part size due to blood flow
pluviograph self-registering rain gauge
pluviometer rain-meter
pneometer instrument that measures respiration
pneumatometer instrument for measuring quantity of air breathed
pneumograph instrument for measuring and recording respiration
polarimeter instrument for measuring polarised light
polariscope instrument for detecting polarized light
polygraph instrument for measuring small changes in pulse and respiration
porometer instrument for measuring degree of porosity
poroscope instrument for investigating porosity
potentiometer instrument for measuring electromotive forces
potometer instrument measuring rate at which plants absorb water
prisoptometer instrument for measuring degree of astigmatism
proctoscope instrument for examining the rectum
psophometer instrument measuring audible interference of electrical current
psychograph instrument that supposedly records spirit messages
psychrometer instrument for measuring air moisture or temperature
psychrometer instrument for measuring dryness of the atmosphere
pulsimeter instrument for measuring the pulse
pycnometer instrument for measuring specific gravity or density
pyknometer instrument for measuring specific gravities
pyranometer instrument measuring solar radiation from the sky's whole hemisphere
pyrgeometer instrument for measuring radiation from earth
pyrheliometer instrument for measuring heating effect of sun
pyrometer instrument for measuring very high temperatures
pyroscope instrument for measuring intensity of radiant heat
qualimeter apparatus for measuring penetrating power of X-ray beams
quantimeter apparatus for measuring quantity of X-rays
quantometer instrument for measuring proportions of elements in metallic samples
rachiometer instrument for measuring the spine
radarscope instrument for detecting radar signals
radiogoniometer instrument for finding direction through radio signals
radiometeorograph instrument for measuring atmospheric conditions at high altitude
radiometer instrument measuring radiation energy
radioscope instrument for viewing objects using X-rays
ratemeter instrument for measuring counting rate of electronic counters
recipiangle old instrument with two arms used for measuring angles
reflectometer instrument for measuring reflectance of radiant energy
refractometer instrument measuring refraction of light
respirometer instrument for measuring and studying respiration
retinoscope instrument for measuring and viewing the retina
rheometer instrument that measures current
rhinoscope instrument for examining the nose
rhythmometer instrument for measuring speed of rhythms
riometer instrument for measuring absorbed cosmic radio waves
rotameter old instrument for measuring length of curved lines
rotameter instrument consisting of glass tube with free float for measuring liquid flow
saccharimeter instrument for measuring amount of sugar in a solution
salinometer instrument for measuring amount of salt in a solution
scintillometer instrument measuring scintillation of star
scintilloscope instrument for measuring gamma rays emitted by a radioactive body
sclerometer instrument measuring hardness
scoliometer instrument measuring curvature
scotograph instrument for writing without seeing
scotoscope instrument for detecting objects in darkness
seismograph instrument for recording earthquakes
seismometer instrument for measuring earthquake intensity
seismoscope instrument for detecting earthquakes
selenoscope instrument for viewing the moon
sensitometer instrument for measuring sensitivity of photographic material
sepometer instrument for measuring septic matter in the air
serimeter instrument for testing quality of silk
shuftiscope instrument used to explore interior of dysentery case
siccimeter instrument for measuring liquid evaporation
sideroscope instrument using magnets to detect presence of iron
sigmoidoscope instrument for examining the interior of the rectum and sigmoid colon
sillometer instrument measuring speed of ship
skiascope instrument for measuring eye's refraction from movement of shadows
snooperscope instrument for viewing infrared radiation
solarimeter instrument for measuring solar radiation
sonograph instrument for recording and analysing sound
spectrofluorimeter instrument for measuring and recording fluorescence spectra
spectrograph instrument for viewing a spectrum
spectroheliograph instrument for taking pictures of the sun
spectroheliokinematograph camera for taking pictures of the sun
spectrohelioscope instrument for viewing solar disc in light of a single wavelength
spectrometer instrument measuring wavelengths of light of a spectrum
spectrophotometer instrument for measuring speed of different parts of light spectrum
spectroscope instrument for forming spectra by dispersing rays of light
speedometer instrument for measuring velocity
spherometer instrument measuring curvature
sphygmograph instrument for recording pulse
sphygmomanometer instrument for measuring arterial blood pressure
sphygmometer instrument for measuring arterial blood pressure
sphygmoscope instrument for making arterial pulsations visible
spinthariscope instrument for visually detecting alpha particles
spirograph instrument recording movements of breathing
spirometer instrument measuring lung capacity
stactometer pipette with hollow bulb for counting drops
stadiometer instrument for measuring the length of a curved line
stagmometer instrument for measuring number of drops in volume of liquid
stalagmometer instrument for measuring surface tension by drops
statoscope instrument for measuring small changes in atmospheric pressure
stauroscope instrument for studying structure of crystals with polarised light
stenometer instrument for measuring distances
stereometer instrument for measuring specific gravity
stereoscope instrument for viewing special three-dimensional photographs
stethometer instrument measuring chest expansion during breathing
stethoscope instrument for detecting sounds produced by the body
strabismometer instrument measuring degree of squinting
strabometer instrument for measuring strabismus in the eyes
stroboscope instrument for studying motion using flashes of light
stylometer instrument for measuring columns
swingometer instrument for measuring swing in votes during an election
sympiesometer instrument for measuring pressure of a current
synchroscope instrument for detecting whether two moving parts are synchronized
tacheometer instrument for rapidly measuring survey points on a map
tachistoscope instrument for rapidly showing images on a screen to test perception
tachograph instrument for recording speed of rotation
tachometer instrument for measuring speed of rotation
taseometer instrument for measuring stress in a structure
tasimeter instrument for measuring changes in pressure
taximeter instrument for measuring fee for hired vehicle
telemeter instrument for measuring strain or distance from observer
telescope instrument for viewing objects at great distances
telespectroscope instrument for analysing radiation omitted by distant bodies
telestereoscope instrument for viewing distant objects stereoscopically
tellurometer instrument using microwaves to measure distance
tenderometer instrument for measuring tenderness of fruits and vegetables
tensimeter instrument for measuring vapour pressure
tensiometer instrument for measuring tension
thalassometer instrument for measuring tides
thermograph instrument for recording changes in temperature
thermometer instrument for measuring temperature
thermometrograph instrument for recording changes in temperature
thermoscope instrument indicating change in temperature
thoracoscope instrument for viewing the thorax and chest wall
tiltmeter instrument for measuring tilting of earth's surface
tocodynamometer instrument for measuring uterine contractions during childbirth
tomograph instrument for viewing section of an object using X-rays
tonometer instrument measuring pitch of musical tones
topophone instrument to determine direction and distance of a fog-horn
torsiograph instrument for recording torsional vibrations on an object
transmissometer instrument for measuring transmission of light through a fluid
trechometer instrument for determining distance travelled; odometer
tremograph instrument for recording involuntary muscular motion
tribometer instrument measuring friction
trigonometer instrument for solving triangles
trocheameter instrument counting wheel's revolutions
tromometer instrument for measuring slight earthquake shocks
tropometer instrument measuring rotation
turbidimeter instrument for measuring turbidity of liquids
turgometer instrument for measuring turgidity
typhlograph instrument to help the blind write clearly
udometer instrument for measuring rainfall
ultramicroscope instrument for viewing extremely small objects
urethroscope instrument for viewing the interior of the urethra
urinometer instrument for measuring specific gravity of urine
vaporimeter instrument for measuring vapour pressure
variometer instrument for measuring magnetic declination
velocimeter instrument for measuring velocity
velometer instrument for measuring speed of air
viameter instrument for measuring revolutions of a wheel
vibrograph instrument for recording vibrations
vibrometer instrument for measuring vibrations
viscometer instrument for measuring viscosity
visometer instrument for measuring focal length of the eye
voltameter instrument for measuring electrical current indirectly
voltmeter instrument for measuring electrical potential
volumenometer instrument for measuring volume of a solid
volumeter instrument for measuring volume of a liquid or gas
wattmeter instrument for measuring electrical power
wavemeter instrument for measuring wavelengths
weatherometer instrument for measuring weather-resisting properties of paint
xanthometer instrument for measuring colour of sea or lake water
xylometer instrument measuring specific gravity of wood
zymometer instrument for measuring fermentation
zymosimeter instrument for measuring fermentation
Annealing is a heat treatment wherein a material is altered, causing changes in its properties such as strength and hardness. Annealing is used to induce ductility, soften material, relieve internal stresses, refine the structure by making it homogeneous, and improve cold working properties.
Electroplating is a plating process in which metal ions, in a solution, are moved by an electric field to coat an electrode. Electroplating is primarily used for depositing a layer of material to bestow a desired property (e.g., abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.) to a surface that otherwise lacks that property.
Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting.
Vulcanization is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur or other equivalent "curatives." A vast array of products is made with vulcanized rubber including tires, shoe soles, hoses, and hockey pucks.
Gestation period, for mammals, is the time in which a fetus develops, beginning with fertilization and ending at birth.[1] The duration of this period varies between species.
Brass gets discoloured in air because of the presence of which of the following gases in air?
A. Oxygen
B. Hydrogen sulphide
C. Carbon dioxide
D. Nitrogen
Which of the following is a non metal that remains liquid at room temperature?
A. Phosphorous
B. Bromine
C. Chlorine
D. Helium
Chlorophyll is a naturally occurring chelate compound in which central metal is
A. copper
B. magnesium
C. iron
D. calcium
Which of the following is used in pencils?
A. Graphite
B. Silicon
C. Charcoal
D. Phosphorous
Which of the following metals forms an amalgam with other metals?
A. Tin
B. Mercury
C. Lead
D. Zinc
Chemical formula for water is
A. NaA1O2
B. H2O
C. Al2O3
D. CaSiO3
The gas usually filled in the electric bulb is
A. nitrogen
B. hydrogen
C. carbon dioxide
D. oxygen
Washing soda is the common name for
A. Sodium carbonate
B. Calcium bicarbonate
C. Sodium bicarbonate
D. Calcium carbonate
Quartz crystals normally used in quartz clocks etc. is chemically
A. silicon dioxide
B. germanium oxide
C. a mixture of germanium oxide and silicon dioxide
D. sodium silicate
Which of the gas is not known as green house gas?
A. Methane
B. Nitrous oxide
C. Carbon dioxide
D. Hydrogen
1. LPG: Liquefied Petroleum Gas
2. TNT: Tri Nitro Toluene
3. RNA: Ribonucleic Acid
4. CNG: Compressed Natural Gas
5. ATP: Adenosine Tri Phosphate
6. RBC: Red Blood Cells/Corpuscles
7. ECG: Electro Cardio Gram
8. PVC: Poly vinyl Chloride
9. RAM: Random Access Memory
10. CFC: Chloro Fluoro Carbon
11. LASER: Light Amplification by Stimulated emission of Radiation
12. RADAR: Radio Detection And Ranging
13. AIDS: Acquired Immune Deficiency Syndrome
14. ROM: Read Only Memory
15. LAN: Local Area Network
16. WWW: World Wide Web
17. DNA: Deoxyribonucleic Acid
18. SONAR: Sound Navigation And Ranging
19. SARS: Severe Acute Respiratory Syndrome
20. NTP: Network Time Protocol/ Normal Temperature and Pressure
21. RQ: Respiratory Quotient
22. NPN: Negative Positive Negative/
23. PNP: Purine Nucleoside Phosphorylase
24. WAN: Wide Area Network
25. CPU: Central Processing Unit
26. BCG: Bacillus Calmette Guerin
27. STP: Standard Temperature And Pressure/Shielded Twisted Pair/Sodium Tripolyphosphate/Spanning Tree Protocol
28. ATP: Adenosine Triphosphate
29. KWh: Kilo Watt Hour
30. BTU: British thermal Unit
31. LDL: Low Density Lipoprotein
32. MAF: Million Acre Feet
33. HDL: Hardware Description Language
34. MCV: Mean Corpuscular Volume
35. UHF: Ultra High Frequency
36. LED: Light emitting Diode
37. LCD: Liquid Crystal Display
38. BASIC: Beginner’s All-Purpose Symbolic Instruction Code
39. MASER: Microwave Amplification by Stimulated Emission of Radiation
40. ETT: Educational Telecommunications and Technology/ European Transaction on Telecommunication
41. HST: High Speed Technology/ High Speed Train (in UK)/Hubble Space Telescope
42. DBS: Data Base Server/ Direct Broadcast Satellite
43. CRO: Cathode Ray Oscilloscope
44. BOT: Build, Operate and Transfer/Botulinum Toxin
45. AMU: Atomic Mass Unit
46. EMF: Electro Motive force
47. ADH: Anti-diuretic Hormone
48. GeV: Giga Electro Volt
49. CRT: Cathode Ray Tube
50. CNS: Central Nervous System
51. PTFE: Poly Tetra Fluoro Ethylene
52. GUT: Grand Unified Theory
53. LONAR: Long Range Navigation
54. MeV: Mega Electron Volt/ Million Electron Volt/ Multi-experiment Viewer
55. AWACS: Airborne Warning and Control System
56. CCTV: Closed-Circuit Television
1. Force: Newton/ Dyne
2. Temperature: Kelvin/ Celsius/ Degree
3. Current: Ampere
4. Heat: Joule/ Calorie/ BTU
5. Pressure: Pascal/Torr
6. Radioactivity: Becquerel/Curie/Rutherford
7. Atomic energy: Rydberg/Joule
8. Voltage: Volt
9. Electric Potential Difference: Volt
10. Electric Charge: Coulomb
11. Power: Watt
12. Resistance: Ohm
13. Conductivity: Mho
14. Energy: Joule/ Erg
15. Distance Between Stars And Planets: Light Year
16. Wavelength: Angstrom
17. Volume: Acre-Foot/Litre
18. Frequency: Hertz
19. Rate of flow of water: Cusec
20. Length: Meter/Fermi/Parsec
21. Optical Power Of A Lens or A Curved Mirror: Dioptre
22. Plane Angle: Radian
23. Luminous Intensity: Candela
24. Amount of Substance: Mole
25. Rate Of Decay Of Radioactive Material: Rutherford
26. Sedimentation Rate: SVEDBERG Unit
27. Induction: Henry
28. Magnetic flux: Maxwell/ Weber
29. Magnetic Flux Density/Magnetic Inductivity: Telsa/Gauss
30. Electric Conductance: Siemens
31. Angle: Degree
32. Solid Angle: Steradian
33. Torque: Foot-Pound
34. Mass: Slug
35. Volume of Water Reservoirs: Acre-foot
36. Mechanical work/Energy: Erg
37. Magneto Motive Force: Gilbert
38. Newton: Force
39. Dyne: Force
40. Kelvin: Temperature
41. Celsius: Temperature
42. Degree: Temperature
43. Ampere: Current
44. Joule: Heat/Atomic Energy/Energy
45. Calorie: Heat
46. BTU: Heat
47. Pascal: Pressure
48. Torr: Pressure
49. Becquerel: Radioactivity
50. Curie: Radioactivity
51. Rutherford: Rate Of Decay Of Radioactive Material/Radioactivity
52. Rydberg: Atomic Energy
53. Volt: Voltage/Electron Potential Difference
54. Coulomb: Electric Charge
55. Watt: Power
56. Ohm: Resistance
57. Mho: Conductivity
58. Erg: Energy
59. Light Year: Distance Between Stars
60. Angstrom: Wavelength
61. Litre: Volume
62. Acre Foot: Volume
63. Hertz: Frequency
64. Cusec: Rate Of Flow Of Water
65. Meter: Length
66. Fermi: Length
67. Parsec: Length
68. Dioptre: Optical Power Of Lens
69. Radian: Plane Angle
70. Candela: Luminous Intensity
71. SVEDBERG: Sedimentation Rate
72. Henry: inductance
73. Maxwell: Magnetic Flux
74. Weber: Magnetic Flux
75. Tesla: Magnetic Flux Density/Magnetic Inductivity
76. Gauss: Magnetic Flux Density/Magnetic Inductivity
77. Siemens: Electric Conductance
78. Degree: Angle
79. Steradian: Solid Angle
80. Foot Pound: torque
81. Slug: Mass
82. Erg: Mechanical Work/Energy
83. Gilbert: Magneto Motive Force
1. Structure Of DNA: Watson & Crick
2. Rabies Vaccination: Louis Pasteur
3. Penicillin: Alexander Fleming
4. Genetic Laws of Heredity: Mendel
5. Vaccination Against Small Pox: Edward Jenner
6. Solar System: Copernicus
7. Current Electricity: Volta
8. Telephone: Graham Bell
9. Gramophone: Thomas Edison
10. Atomic Number: Mosley
11. Mercury Thermometer: Fahrenheit
12. Dynamite: Alfred Noble
13. Cell: Robert Hooke
14. Television: John Baird
15. X-rays: Roentgen
16. Circulation Of Blood: William Harvey
17. Bicycle: Macmillan
18. Wireless Telegraphy: Signor Marconi
19. Microorganisms: Antoni Van Leeuwenhoek
20. Laser: Dr. C. Gilbert
21. Periodic Table: Mendeleev
22. Radium: Madam Marie Curie
23. Mass/Energy Conversion Equation: Einstein
24. Cement: Joseph Aspdin
25. Simple Microscope: Hans Janssen and Zacharias Janssen
26. Sulphuric, Nitric and Hydrochloric Acid: Jabir Bin Hayan
27. Jet Engine: Frank Whittle
28. Electricity: Thomas Edison
29. Computer: Charles Babbage
30. Lightening Conductor: Benjamin Franklin
31. Semiconductor: Bardeen and Brattain
32. Uncertainty Principle: Heisenberg
33. Cyclotron: Ernest Lawrence
34. Electro Magnetic Engine: James Maxwell
35. Internal Combustion Engine: Nikolas August Otto
36. Earth As A Huge Magnet: William Gilbert
37. First Person To Orbit Earth: Yuri Gagarin
38. Water: Henry Cavendish
39. Gravitation: Newton
40. Magnet: Dr. Gilbert
41. E.M Induction: Faraday
42. Energy Quanta: Max Planck
44. First Clone Of A Sheep: Ian Wilmit
45. Streptomycin: S.A.Waksman
46. Helical Structure Of Protein: Linus Pauling
47. Polio Vaccine: Jonas Salk
48. Nylon: Wallace. H Carothers
49. Radioactivity: Becquerel
50. Safety Match: John Walker
51. Gun Powder: Roger Bacon
52. Jupiter: Galileo
53. Neutron: James Chadwick
54. Earth’s Radius: Eratosthenes
55. Oxygen: Joseph Priestley
56. Noble Gases: Cavendish
57. Synthesis Of Gene In Laboratory: Hargobind Khorana
58. Earth Revolves Round The Sun: Copernicus
59. Binomial Nomenclature: Carl Von Linnaeus
60. North America: Christopher Columbus
61. Green Land: Robert Peary
62. Transistor: William Bradford Shockley
63. Typewriter: Sholes
64. Bacteriology: Pasteur
65. Laser: Theodore Maiman
66. Father Of Botany: Theophrastus
67. Father Of Zoology: Aristotle
68. Father Of Taxonomy: Carolus Linnaeus
69. Father Of Genetics: Gregor Mendel
70. Cell Theory: Scheilden And Schwann
71. Cholera Bacillus: Robert Koch
72. Theory Of Relativity And Photoelectric Effect: Einstein
73. Insulin: Dr. F.G Banting
74. Nucleus: Robert Brown
75. Chromosome: Waldeyer
76. Ultra Violet Rays: Johann Wilhelm Ritter
77. Law Of Attraction And Repulsion Between Electric Charges: Coulomb
78. Battery: Alessandro Volta
79. Electromagnetic theory: James Clerk Maxwell
80. First Person To Televise Pictures Of Moving Objects: John Logie Baird
81. Antiseptic Medicine: Joseph Lister
82. Cotton Gin: Eli Whitney
83. Big Bang Theory: Georges Lemaitre
84. Electron: J.J Thomson
85. Aeroplane: Wilbur and Orville Wright
86. Steam Railway Locomotive: Richard Trevithick
87. Radio: Marconi
88. Household Vacuum Cleaner: Herbert Cecil Booth
89. Bakelite: Baekeland
90. Windscreen Wipers: Marry Anderson
91. Ballpoint pen: Laszlo And Georg Biro
92. Helicopter: Igor Sikorsky
93. DDT: Paul Muller
94. Blood Banking: Charles Drew
95. AK-47: Mikhail Kalashnikov
96. Integrated Circuit: Robert Noyce
97. Cellular Phone: Dr. Martin Cooper
98. Vitamins: Funk
99. Uranus: Herschel
100. Calculating Machine: Blaise Pascal
101. Tuberculosis: Robert Koch
102. Logarithm Table: John Napier
103. Malaria Parasite: Ronald Ross
104. Zero: Al Khwarizmi
105. Velocity Of Light: Roomer
1. Pressure: Barometer
2. Voltage: Voltmeter
3. Purity Of Milk: Lactometer
4. Temperature: Thermometer
5. Velocity Of Wind: Anemometer
6. Earthquake: Richter Scale
7. Degree Of Humidity: Hygrometer
8. Blood Pressure: Sphygmomanometer
9. Radioactivity: Geiger Counter
10. High Temperature: Pyrometer
11. Rainfall: Rain Guage
12. Earthquake Recording: Seismograph
13. Electric current: Ammeter
SHOTY QUESTIONS
1. Question: A man with a load jumps from a high building. What will be the load experienced by him?
Answer: Zero, because while falling, both the man and the load are falling at the same acceleration i.e. Acceleration due to gravity.
2. Question: A piece of chalk when immersed in water emits bubbles. Why?
Answer: Chalk consists of pores forming capillaries. When it is immersed in water, the water begins to rise in the capillaries and air present there is expelled in the form of bubbles.
3. Question: Why does a liquid remain hot or cold for a long time inside a thermos flask?
Answer: The presence of air, a poor conductor of heat, between the double glass wall of a thermos flask, keeps the liquid hot or cold inside a flask for a long time.
4. Question: Why does a ball bounce upon falling?
Answer: When a ball falls, it is temporarily deformed. Because of elasticity, the ball tends to regain its original shape for which it presses the ground and bounces up (Newton's Third Law of Motion).
5 Question: Why is standing in boats or double decker buses not allowed, particularly in the upper deck of buses?
Answer: On tilting the centre of gravity of the boat or bus is lowered and it is likely to overturn.
6. Question: Why is it recommended to add salt to water while boiling dal?
Answer: By addition of salt, the boiled point of water gets raised which helps in cooking the dal sooner.
7. Question: Why is it the boiling point of sea water more than that of pure water?
Answer: Sea water contains salt, and other impurities which cause an elevation in its boiling point.
8. Question: Why is it easier to spray water to which soap is added?
Answer: Addition of soap decreases the surface tension of water. The energy for spraying is directly proportional to surface tension.
9. Question: Which is more elastic, rubber or steel?
Answer: Steel is more elastic for the same stress produced compared with rubber.
10. Question: Why is the sky blue?
Answer: Violet and blue light have short waves which are scattered more than red light waves. While red light goes almost straight through the atmosphere, blue and violet light are scattered by particles in the atmosphere. Thus, we see a blue sky.
11. Question: Why Does ink leak out of partially filled pen when taken to a higheraltitude?
Answer: As we go up, the pressure and density of air goes on decreasing. A Partially filled pen leaks when taken to a higher altitude because the pressure of air acting on the ink inside the tube of the pen is greater than the pressure of the air outside.
12. Question: On the moon, willthe weightof a man be less or more than his weight on the earth?
Answer: The gravity of the moon is one-sixth that of the earth; hence the weight of a person on the surface of the moon will be one-sixth of his actual weight on earth.
13. Question: Why do some liquid burn while others do not?
Answer: A liquid burns if its molecules can combine with oxygen in the air with the production of heat. Hence, oil burns but water does not.
14. Question: Why can we see ourselves in a mirror?
Answer: We see objects when light rays from them reach our eyes. As mirrors have a shiny surface, the light rays are reflected back to us and enter our eyes.
15. Question: Why does a solid chunk of ironsinkin water but float in mercury?
Answer: Because the density of iron is more than that of water bus less than that of mercury.
16. Question: Why is cooking quicker in a pressure cooker?
Answer: As the pressure inside the cooker increases, the boiling point of water is raised, hence, the cooking process is quicker.
17. Question: When wood burns it crackles. Explain?
Answer: Wood contains a complex mixture of gases and tar forming vapors trapped under its surface. These gases and tar vapors escape, making a cracking sound.
18. Question: Why do stars twinkle?
Answer: The light from a star reaches us after refraction as it passes through various layers of air. When the light passes through the earth?S atmosphere, it is made to flicker by the hot and cold ripples of air and it appears as if the stars are twinkling.
19. Question: Why is it easier to roll a barrel than to pull it?
Answer: Because the rolling force of friction is less than the dynamic force of sliding friction.
20. Question: If a feather, a wooden ball and a steel ball fall simultaneously in a vacuum, which one of these would fall faster?
Answer: All will fall at the same speed in vacuum because there will be no air resistance and the earth?S gravity will exert a similar gravitational pull on all.
21. Question: When a man fires a gun, he is pushed back slightly. Why?
Answer: As the bullet leaves the nozzle of the gun?S barrel with momentum in a forward direction, as per Newton's Third Law of Motion, the ejection imparts to the gun as equal momentum in a backward direction.
22. Question: Ice wrapped in a blanket or saw dust does not melt quickly. Why?
Answer: Both wood and wool are bad conductors of heat. They do not permit heat rays to reach the ice easily.
23. Question: Why do we perspire on a hot day?
Answer: When the body temperature rises, the sweat glands are stimulated to secrete perspiration. It is nature's way to keep the body cool. During the process of evaporation of sweat, body heat is taken away, thus giving a sense of coolness.
24. Question: Why does ice float on water butsinkin alcohol?
Answer: Because ice is lighter than water it floats on it. However, ice is heavier than alcohol and therefore it sinks in alcohol.
25. Question: Why do we perspire before rains?
Answer: Before the rain falls, the atmosphere gets saturated with water vapors; as a result, the process of evaporation of sweat is delayed.
26. Question: Why does athermometerkept in boiling water show no change in reading after 1000C?
Answer: The boiling point of water is 1000C. Once water starts boiling at this temperature, thermometer records no change in temperature. The quantity of heat supplied is being utilized as latent heat of evaporation to convert the water at boiling point into vapour.
27. Question: Why do we bring our hands close to the mouth while shouting across to someone far away?
: By keeping hands close to mouth the sound is not allowed to spread (Phenomenon of diffraction of sound) in all direction, but is directed to a particular direction and becomes louder.
28. Question: Why does a corked bottle filled with water burst if left out on a frosty night?
Answer: Because of low temperature the water inside the bottle freezes. On freezing it expands, thereby its volume increases and pressure is exerted on the walls.
29. Question: Why is a small gap left at the joint between two rails?
Answer: To permit expansion of rails due to heat generated by friction of a moving train.
30. Question: Why cannot a copper wire be used to make elements inelectric heater?
Answer: Copper melts at 108.30C and forms a black powder on reacting with atmospheric oxygen. For heater elements a metal should have more resistance to produce heat.31. Question: Why are water or mercury droplets always round when dropped on a clean glass?
Answer: The surface of a liquid is the seat of a special force as a result of which molecules on the surface are bound together to form something like a stretched membrane. They tend to compress the molecules below to the smallest possible volume, which causes the drop to take a round shape as for a given mass he sphere has minimum volume.
32. Question: Why does a balloon filled with hydrogen rise in the air?
Answer: Weight of hydrogen is less than the weight of air displaced by it. In balloons hydrogen is normally filled because it is lighter than air.
33. Question: Why do we lean forward while climbing a hill?
Answer: In order to keeps the vertical line passing through our centre of gravity always between our feet, which is essential to attain equilibrium or stability.
34. Question: Why does smoke curl up in the air?
Answer: Smoke contains hot gases which being lighter in weight, follows a curved path because of the eddy currents that are set up in the air.
35. Question: Why does an electric bulb explode when it is broken?
Answer: The bulb encompasses partial vacuum and as it breaks, air rushes in causing a small explosion.
36. Question: Why does a man fall forward when he jumps out of a running train or bus?
Answer: He is in motion while in the train or bus. When he jumps out, his feet comes to rest while touching the ground but his upper portion which is still in motion propels him forward.
37. Question: Why does an ordinary glass tumbler crack when very hot tea or milk is poured in it?
Answer: When a hot liquid is poured into a tumbler, the inner layer of the tumbler gets heated, it expands before the outer layer and an unequal expansion of both layers causes the tumbler to crack.
38. Question: Why is a compass used as an indicator of direction?
Answer: The magnetic needles of a compass under the influence f the earth?S magnetic field lie in a north-south direction. Hence, we can identify direction.
39. Question: Why is water from a hand pump warm in winter and cold in summer? Answer: In winter, the outside temperature is lower than that of water flowing out of the pump, and therefore, the water is warm. Whereas in summer, the outside temperature is higher than the water of the pump, and therefore, it feels cold.
40. Question: Why is a rainbow seen after a shower?
Answer: After a shower, the clouds containing water droplets act like a prism through which the white light is dispersed producing a spectrum.
Question: Why does a swimming pool appear less deep than is actually is?
Answer: The rays of light coming from the bottom of the pool pass from a denser medium (water) to a rarer medium (air) and are refracted (bend away from the normal). When the rays return to the surface, they form an image of the bottom of the pool at a point, which is little above the real position.
42. Question: Why is one?S breath visible in winter but not in summer?
Answer: In winter, water vapor contained in the breath condenses into small droplets, which become visible but in summer they are quickly evaporated and not seen.
43. Question: Why doesn?T the electric filament in an electric bulb burn up?
Answer: Firstly, because is made of tungsten which has a very high melting point (34100C) whereas the temperature of the filament required to glow is only 2700oc. Secondly, oxygen is absent since the bulb is filled with an inert gas which does not help in burning.
44. Question: Why does blotting paper absorb ink?
Answer: Blotting paper has fine pores, which act like capillaries. When a portion of blotting paper is brought in contact with ink, ink enters the pores due to surface tension (capillary action f liquids) and is absorbed.
45. Question: Why does a small iron sink in water but a large ship float?
Answer: The weight of water displaced by an iron ball is less than its own weight, whereas water displaced by the immersed portion of a ship is equal to its weight (Archimedes? Principle).
46. Question: Why does ice float on water?
Answer: The weight of the ice block is equal to the weight of the liquid displaced by the immersed portion of the ice.
47. Question: Why does moisture gather outside a tumbler containing cold water?
Answer: The water vapour in the air condenses on cooling and appears as droplets of water.
48. Question: Why does kerosene float on water?
Answer: Because the density of kerosene is less than that of water. For the same reason cream rises in milk and floats at the top.
49. Question: Why is the water in an open pond cool even on a hot summer day?
Answer: As the water evaporates from the open surface of a pond, heat is taken away in the process, leaving the surface cool.
50. Question: Why is it less difficult to cook rice or potatoes at higher altitudes?
Answer: Atmospheric pressure at higher altitudes is low and boils water below 100C. The boiling point of water is directly proportional to the pressure on its surface.
51. Question: Why is it difficult to breathe at higher altitudes?
Answer: Because of low air pressure at higher altitudes the quantity of air is less, and so that of oxygen.
52. Question: Why are winter nights and summer nights warmer during cloudy weather than when the sky is clear?
Answer: Clouds being bad conductors of heat do not permit radiation of heat from land to escape into the sky. As this heat remains in the atmosphere, the cloudy nights are warmer.
53. Question: Why is a metal tyre heated before it is fixed on wooden wheels?
Answer: On heating, the metal tyre expands by which its circumference also increases. This makes fixing the wheel easier and therefore cooling down shrinks it; thus fixing the tyre tightly.
54. Question: Why is it easier to swim in the sea than in a river?
Answer: The density of sea water is higher; hence the up thrust is more than that of river water.
55. Question: Who will possibly learn swimming faster-a fat person or a thin person?
Answer: The fat person displaces more water which will help him float much more freely compared to a thin person.
56. Question: Why is a flash of lightening seen before thunder?
Answer: Because light travels faster than sound, it reaches the earth before the sound of thunder.
57. Question: Why cannot a petrol fire be extinguished by water?
Answer: Water, which is heavier than petrol, slips down permitting the petrol to rise to the surface and continue to burn. Besides, the existing temperature is so high that the water poured on the fire evaporates even before it can extinguish the fire. The latter is true if a small quantity of water is poured.
58. Question: Why does water remain cold in an earthen pot? Answer: There are pores in an earthen pot which allow water to percolate to the outer surface. Here evaporation of water takes place thereby producing a cooling effect.
59. Question: Why do we place a wet cloth on the forehead of a patient suffering from high temperature?
Answer: Because of body?S temperature, water evaporating from the wet cloth produces a cooling effect and brings the temperature down.
60. Question: When a needle is placed on a small piece of blotting paper which is place on the surface of clean water, the blotting paper sinks after a few minutes but the needle floats. However, in a soap solution the needle sinks. Why?
Answer: The surface tension of clean water being higher than that of a soap solution, it cans support the weight of a needle due to its surface tension. By addition of soap, the surface tension of water reduces, thereby resulting in the sinking of the needle.61. Question: To prevent multiplication of mosquitoes, it is recommended to sprinkle oil in the ponds with stagnant water. Why?
Answer: Mosquitoes breed in stagnant water. The larvae of mosquitoes keep floating on the surface of water due to surface tension. However, when oil is sprinkled, the surface tension is lowered resulting in drowning and death of the larvae.
62. Question: Why does oil rise on a cloth tape of an oil lamp?
Answer: The pores in the cloth tape suck oil due to the capillary action of oil.
63. Question: Why are ventilators in a room always made near the roof?
Answer: The hot air being lighter in weight tends to rise above and escape from the ventilators at the top. This allows the cool air to come in the room to take its place.
64. Question: How does ink get filled in a fountain pen?
Answer: When the rubber tube of a fountain pen immersed in ink is pressed, the air inside the tube comes out and when the pressure is released the ink rushes in to fill the air space in the tube.
65. Question: Why are air coolers less effective during the rainy season?
: During the rainy reason, the atmosphere air is saturated with moisture. Therefore, the process of evaporation of water from the moist pads of the cooler slows down thereby not cooling the air blown out from the cooler.
66. Question: Why does grass gather more dew in nights than metallic objects such as stones?
Answer: Grass being a good radiator enables water vapour in the air to condense on it. Moreover, grass gives out water constantly (transpiration) which appears in the form of dew because the air near grass is saturated with water vapour and slows evaporation. Dew is formed on objects which are good radiations and bad conductors.
67. Question: If a lighted paper is introduced in a jar of carbon dioxide, its flame extinguishes. Why?
Answer: Because carbon dioxide does not help in burning. For burning, oxygen is required.
68. Question: Why does the mass of an iron increase on rusting?
Answer: Because rust is hydrated ferric oxide which adds to the mass of the iron rod. The process of rusting involves addition of hydrogen and oxygen elements to iron.
69. Question: Why does milk curdle?
Answer: Lactose (milk sugar) content of milk undergoes fermentation and changes into lactic acid which on reacting with milk protein (casein) form curd.
70. Question: Why does hard water not lather soap profusely?
Answer: Hard water contains sulphates and chlorides of magnesium and calcium which forms an insoluble compound with soap. Therefore, soap does not lather with hard water.
71. Question: Why is it dangerous to have charcoal fire burning in a closed room?
Answer: When charcoal burns it produces carbon monoxide which is suffocating and can cause death.
72. Question: Why is it dangerous to sleep under trees at night?
Answer: Plants respire at night and give out carbon dioxide which reduces the oxygen content of air required for breathing.
73. Question: Why is a new quilt warmer than an old one?
Answer: In a new quilt the cotton is not compressed and as such it encloses more air which is bad conductor of heat. Therefore, it does not allow heat to pass.
74. Question: Curved rail tracks or curved roads are banked or raised on one side. Why?
Answer: Because a fast moving train or vehicle leans inwards while taking turn and the banked or raised track provides required centripetal force to enable it to move round the curve.
75. Question: How do bats fly in dark?
Answer: When bats fly they produce ultrasonic sound waves which are reflected back to them from the obstacles in their way and hence they can fly without difficulty.
76. Question: Water pipes often burst at hill stations on cold frosty nights. Why? Answer: The temperature may fall below 00C during cold frosty nights which converts the water inside the pipes into ice, resulting in an increase in volume. This exerts great force on the pipes and as a result, they burst.
. Question: Why are white clothes more comfortable in summer than dark or black ones?
Answer: White clothes are good reflectors and bad absorbers of heat, whereas dark or black clothes are good absorbers of heat. Therefore, white clothes are more comfortable because they do not absorb heat from the sun rays.
78. Question: Why does a rose appear red grass green in daylight?
Answer: Rose absorbs all the constituent colors of white light except red which is reflected to us. Similarly, grass absorbs all colors except green which is reflected t us.
79. Question: Why does a ship rise as it enters the sea from a river?
Answer: The density of sea water is high due to impurities and salts compared to river water as a result; the upthurst produced by the sea water on the ship is more than that of river water.
80. Question: Why are fuse provided in electric installations?
Answer: A safety fuse is made of a wire of metal having a very low melting point. When excess current flows in, the wire gets heated, melts and breaks the circuit. By breaking the circuit it saves electric equipment or installations from damage by excessive flow of current.
81. Question: Why is it easier to lift a heavy object under water than in air?
Answer: Because when a body is immersed in water, it experiences an upward thrust (Archimedes? Principle) and loses weight equal to the weight of the water displaced by its immersed potion, and hence, is easier to lift objects.
82. Question: If a highly pumped up bicycle tyre is left in the hot sunlight, it bursts. Why?
Answer: The air inside the tube increases in volume when heated up. As sufficient space for the expansion of the air is not available because the tube is already highly pumped, it may result in bursting of the tyre.
83. Question: What will be the color of green in blue light?
Answer: Grass will appear dark in color because it absorbs all other colors of the light except its own green color. The blue light falling on grass will be absorbed by it, and hence, it will appear dark in color.
84. Question: Why do two eyes give better vision than one?
Answer: Because two eyes do not form exactly similar images and he fusion of these two dissimilar images in the brain gives three dimensions of the stereoscopic vision.
1. What is the hottest place on Earth?
Count one wrong if you guessed Death Valley in California. True enough on many days. But El Azizia in Libya recorded a temperature of 136 degrees Fahrenheit (57.8 Celsius) on Sept. 13, 1922 -- the hottest ever measured. In Death Valley, it got up to 134 Fahrenheit on July 10, 1913.
2. And the coldest place around here?
Far and away, the coldest temperature ever measured on Earth was -129 Fahrenheit (-89 Celsius) at Vostok, Antarctica, on July 21, 1983.
3. What makes thunder?
If you thought, "Lightning!" then hats off to you. But I had a more illuminating answer in mind. The air around a lightning bolt is superheated to about five times the temperature of the Sun. This sudden heating causes the air to expand faster than the speed of sound, which compresses the air and forms a shock wave; we hear it as thunder.
4. Can rocks float?
In a volcanic eruption, the violent separation of gas from lava produces a "frothy" rock called pumice, loaded with gas bubbles. Some of it can float, geologists say. I've never seen this happen, and I'm thankful for that.
5. Can rocks grow?
Yes, but observing the process is less interesting than watching paint dry. Rocks called iron-manganese crusts grow on mountains under the sea. The crusts precipitate material slowly from seawater, growing about 1 millimeter every million years. Your fingernails grow about the same amount every two weeks.
6. How much space dust falls to Earth each year?
Estimates vary, but the USGS says at least 1,000 million grams, or roughly 1,000 tons of material enters the atmosphere every year and makes its way to Earths surface. One group of scientists claims microbes rain down from space, too, and that extraterrestrial organisms are responsible for flu epidemics . There's been no proof of this, and I'm not holding my breath.
7. How far does regular dust blow in the wind?
A 1999 study showed that African dust finds its way to Florida and can help push parts of the state over the prescribed air quality limit for particulate matter set by the U.S. Environmental Protection Agency. The dust is kicked up by high winds in North Africa and carried as high as 20,000 feet (6,100 meters), where it's caught up in the trade winds and carried across the sea. Dust from China makes its way to North America, too.
8. Where is the worlds highest waterfall?
The water of Angel Falls in Venezuela drops 3,212 feet (979 meters).
9. What two great American cities are destined to merge?
The San Andreas fault, which runs north-south, is slipping at a rate of about 2 inches (5 centimeters) per year, causing Los Angeles to move towards San Francisco. Scientists forecast LA will be a suburb of the City by the Bay in about 15 million years.
10. Is Earth a sphere?
Because the planet rotates and is more flexible than you might imagine, it bulges at the midsection, creating a sort of pumpkin shape. The bulge was lessening for centuries but now, suddenly, it is growing, a recent study showed. Accelerated melting of Earth's glaciers is taking the blame for the gain in equatorial girth.
11. What would a 100-pound person weigh on Mars?
The gravity on Mars is 38 percent of that found on Earth at sea level. So a 100-pound person on Earth would weigh 38 pounds on Mars. Based on NASA's present plans, it'll be decades before this assumption can be observationally proved, however.
12. How long is a Martian year?
It's a year long, if you're from Mars. To an earthling, it's nearly twice as long. The red planet takes 687 Earth-days to go around the Sun -- compared to 365 days for Earth. Taking into account Mars' different rotational time (see #13 below) calendars on Mars would be about 670 days long with some leap days needed to keep things square. If you find one, please mail it to me. I'm curious how they worked out the months, given they have two moons. [The initial publication of this fact mistakenly said a Mars calendar would have 687 days.]
13. How long is the average Martian day?
A Martian can sleep (or work) and extra half-hour every day compared to you. Mars days are 24 hours and 37 minutes long, compared to 23 hours, 56 minutes on Earth. A day on any planet in our solar system is determined by how long it takes the world to spin once on its axis, making the Sun appear to rise in the morning and sending it down in the evening.
14. What is the largest volcano?
The Mauna Loa volcano in Hawaii holds the title here on Earth. It rises more than 50,000 feet (9.5 miles or 15.2 kilometers) above its base, which sits under the surface of the sea. But that's all volcanic chump change. Olympus Mons on Mars rises 16 miles (26 kilometers) into the Martian sky. Its base would almost cover the entire state of Arizona.
15. What was the deadliest known earthquake?
The world's deadliest recorded earthquake occurred in 1557 in central China. It struck a region where most people lived in caves carved from soft rock. The dwellings collapsed, killing an estimated 830,000 people. In 1976 another deadly temblor struck Tangshan, China. More than 250,000 people were killed.
16. What was the strongest earthquake in recent times?
A 1960 Chilean earthquake, which occurred off the coast, had a magnitude of 9.6 and broke a fault more than 1,000 miles (1,600 kilometers) long. An earthquake like that under a major city would challenge the best construction techniques.
17. Which earthquake was more catastrophic: Kobe, Japan or Northridge, California?
The 1994 Northridge earthquake had a magnitude of 6.7 was responsible for approximately 60 deaths, 9,000 injuries, and more than $40 billion in damage. The Kobe earthquake of 1995 was magnitude 6.8 and killed 5,530 people. There were some 37,000 injuries and more than $100 billion in economic loss.
18. How far is it to the center of the Earth?
The distance from the surface of Earth to the center is about 3,963 miles (6,378 kilometers). Much of Earth is fluid. The mostly solid skin of the planet is only 41 miles (66 kilometers) thick -- thinner than the skin of an apple, relatively speaking.
19. What is the highest mountain?
Climbers who brave Mt. Everest in the Nepal-Tibet section of the Himalayas reach 29,035 feet (nearly 9 kilometers) above sea level. Its height was revised upward by 7 feet based on measurements made in 1999 using the satellite-based Global Positioning System.
20. Has the Moon always been so close?
It used to be much closer! A billion years ago, the Moon was in a tighter orbit, taking just 20 days to go around us and make a month. A day on Earth back then was only 18 hours long. The Moon is still moving away -- about 1.6 inches (4 centimeters) a year. Meanwhile, Earth's rotation is slowing down, lengthening our days. In the distant future, a day will be 960 hours long! [ Find out why]
21. Where is the lowest dry point on Earth?
The shore of the Dead Sea in the Middle East is about 1,300 feet (400 meters) below sea level. Not even a close second is Bad Water in Death Valley, California, at a mere 282 feet below sea level.
22. Good thing California isn't sinking further, right?
Actually parts of it are, which is so interesting that I snuck this non-question onto the list. In a problem repeated elsewhere in the country, the pumping of natural underground water reservoirs in California is causing the ground to sink up to 4 inches (11 centimeters) per year in places. Water and sewage systems may soon be threatened.
23. What is the longest river?
The Nile River in Africa is 4,160 miles (6,695 kilometers) long.
24. What is the most earthquake-prone state in the United States?
Alaska experiences a magnitude 7 earthquake almost every year, and a magnitude 8 or greater earthquake on average every 14 years. Florida and North Dakota get the fewest earthquakes in the states, even fewer than New York .
25. What's the driest place on Earth?
A place called Arica, in Chile, gets just 0.03 inches (0.76 millimeters) of rain per year. At that rate, it would take a century to fill a coffee cup.
26. What causes a landslide?
Intense rainfall over a short period of time can trigger shallow, fast-moving mud and debris flows. Slow, steady rainfall over a long period of time may trigger deeper, slow-moving landslides. Different materials behave differently, too. Every year as much as $2 billion in landslide damage occurs in the United States. In a record-breaking storm in the San Francisco area in January 1982, some 18,000 debris flows were triggered during a single night! Property damage was over $66 million, and 25 people died.
27. How fast can mud flow?
Debris flows are like mud avalanches that can move at speeds in excess of 100 mph (160 kph).
28. Do things inside Earth flow?
You bet. In fact, scientists found in 1999 that molten material in and around Earth's core moves in vortices, swirling pockets whose dynamics are similar to tornadoes and hurricanes. And as you'll learn later in this list, the planet's core moves in other strange ways, too.
29. What is the wettest place on Earth?
Lloro, Colombia averages 523.6 inches of rainfall a year, or more than 40 feet (13 meters). That's about 10 times more than fairly wet major cities in Europe or the United States.
30. Does Earth go through phases, like the Moon?
From Mars, Earth would be seen to go through distinct phases (just as we see Venus change phases). Earth is inside the orbit of Mars, and as the two planets travel around the Sun, sunlight would strike our home planet from different angles during the year. Earth phases can be seen in recent photographs taken by Mars Global Surveyor and the European Mars Express
31. What is the largest canyon?
The Grand Canyon is billed as the world's largest canyon system. Its main branch is 277 miles (446 kilometers) long. But let's compare. Valles Marineris on Mars extends for about 3,000 miles (4,800 kilometers). If added it to a U.S. map, it would stretch from New York City to Los Angeles. In places this vast scar on the Martian surface is 5 miles (8 kilometers) deep.
32. What is the deepest canyon in the United States?
Over the eons, the Snake River dug Hell's Canyon along the Oregon-Idaho border. It is more than 8,000 feet (2.4 kilometers) deep. In contrast, the Grand Canyon is less than 6,000 feet deep -- a bit more than a mile.
33. Is Earth the largest rocky planet in the solar system?
Just barely! Earth's diameter at the equator is 7,926 miles (12,756 kilometers). Venus is 7,521 miles (12,104 kilometers) wide. Mercury and Mars, the other two inner rocky planets, are much smaller. Pluto is rocky, too, but it's comparatively tiny (and some say it is not a planet at all).
34. How many of Earth's volcanoes are known to have erupted in historic time?
About 540 volcanoes on land are known. No one knows how many undersea volcanoes have erupted through history.
35. Is air mostly oxygen?
Earth's atmosphere is actually about 80 percent nitrogen. Most of the rest is oxygen, with tiny amounts of other stuff thrown in.
36. What is the highest waterfall in the United States?
Yosemite Falls in California is 2,425 feet (739 meters).
37. What percentage of the world's water is in the oceans?
About 97 percent. Oceans make up about two-thirds of Earth's surface, which means that when the next asteroid hits the planet, odds are good it will splash down.
38. Which two landmasses contain the vast majority of the Earth's fresh water supply?
Nearly 70 percent of the Earth's fresh-water supply is locked up in the icecaps of Antarctica and Greenland. The remaining fresh-water supply exists in the atmosphere, streams, lakes, or groundwater and accounts for a mere 1 percent of the Earth's total.
39. Which of the Earth's oceans is the largest?
The Pacific Ocean covers 64 million square miles (165 million square kilometers). It is more than two times the size of the Atlantic. It has an average depth of 2.4 miles (3.9 kilometers).
40. Why is Earth mostly crater-free compared to the pockmarked Moon?
Earth is more active, in terms of both geology and weather. Much of our planet's geologic history was long ago folded back inside. Some of that is regurgitated by volcanoes, but the results are pretty hard to study. Even more recent events evident on the surface -- craters that can by millions of years old -- get overgrown by vegetation, weathered by wind and rain, and modified by earthquakes and landslides. The Moon, meanwhile, is geologically quiet and has almost no weather; its craters tell a billions-year-long tale of catastrophic collisions. Interestingly, some of the oldest Earth rocks might be awaiting discovery on the Moon, having been blasted there billions of years ago by the very asteroid impacts that rattle both worlds.
41. How much surface area does Earth contain?
There are 196,950,711 square miles (510,100,000 square kilometers).
42. What is the largest lake in the world?
By size and volume it is the Caspian Sea, located between southeast Europe and west Asia.
43. Where do most earthquakes and volcanic eruptions occur on Earth?
The majority occur along boundaries of the dozen or so major plates that more or less float on the surface of Earth. One of the most active plate boundaries where earthquakes and eruptions are frequent, for example, is around the massive Pacific Plate commonly referred to as the Pacific Ring of Fire. It fuels shaking and baking from Japan to Alaska to South America.
44. How hot are the planet's innards?
The temperature of Earth increases about 36 degrees Fahrenheit (20 degrees Celsius) for every kilometer (about 0.62 miles) you go down. Near the center, its thought to be at least 7,000 degrees Fahrenheit (3,870 Celsius).
45. What three countries have the greatest number of historically active volcanoes?
The top three countries are Indonesia, Japan, and the United States in descending order of activity.
46. How many people worldwide are at risk from volcanoes?
As of the year 2000, USGS scientists estimated that volcanoes posed a tangible risk to at least 500 million people. This is comparable to the entire population of the world at the beginning of the seventeenth century!
47. Which of the following sources stores the greatest volume of fresh water worldwide: lakes, streams or ground water?
Groundwater comprises a 30 times greater volume than all freshwater lakes, and more than 3,000 times what's in the world's streams and rivers at any given time. Groundwater is housed in natural underground aquifers, in which the water typically runs around and through the stone and other material.
48. Which earthquake was larger, the 1906 San Francisco earthquake or the 1964 Anchorage, Alaska, temblor?
The Anchorage earthquake had a magnitude of 9.2, whereas the San Francisco earthquake was a magnitude 7.8. This difference in magnitude equates to 125 times more energy being released in the 1964 quake and accounts for why the Anchorage earthquake was felt over an area of almost 500,000 square miles (1,295,000 square kilometers).
49. Which earthquake was more destructive in terms of loss of life and relative damage costs, the 1906 San Francisco earthquake or the 1964 Anchorage earthquake?
The 1906 San Francisco earthquake tops this category. It was responsible for 700 deaths versus 114 from the Anchorage earthquake. Property damage in San Francisco was also greater in relative terms due to the destructive fires that destroyed mostly wooden structures of the time.
50. Is Earth's core solid?
The inner portion of the core is thought to be solid. But the outer portion of the core appears molten. We've never been there though, so scientists aren't sure of the exact composition. A radical Hollywood-like idea was recently put forth to blow a crack in the planet and send a probe down there to learn more. An interesting bit of recent evidence shows Mars' core may be similarly squishy. Scientists figured this out by studying tides on Mars ( tides on Mars? ).
51. Does all of Earth spin at the same rate?
The solid inner core -- a mass of iron comparable to the size of the Moon -- spins faster than the outer portion of the iron core, which is liquid. A study in 1996 showed that over the previous century, the extra speed caused the inner core to gain a quarter-turn on the planet as a whole. So the inner core makes a complete revolution with respect to the rest of Earth in about 400 years. Immense pressure keeps it solid.
52. How many people have been killed by volcanoes during the last 500 years?
At least 300,000. Between 1980 and 1990, volcanic activity killed at least 26,000 people.
53. How much of the Earth's surface consists of volcanic rock?
Scientists estimate that more than three-quarters of Earth's surface is of volcanic origin-- that is, rocks either erupted by volcanoes or molten rock that cooled below ground and has subsequently been exposed at the surface. Most of Earth's volcanic rocks are found on the sea floor.
54. Can an earthquake cause a tsunami?
If the earthquake originates under the ocean, yes. Near the earthquake's epicenter, the sea floor rises and falls, pushing all the water above it up and down. This motion produces a wave that travels outward in all directions. A tsunami can be massive but remain relatively low in height in deep water. Upon nearing the shore, it is forced up and can reach the height of tall buildings. One in 1964 was triggered in Alaska and swamped the small northern California town of Crescent City, moving train cars several blocks and killing several people there. Asteroids can cause tsunami , too.
55. Are all tsunamis high waves when they strike a coastline?
No, contrary to many artistic images of tsunamis, most do not result in giant breaking waves. Rather, most tsunamis come onshore more like very strong and fast tides. The water can rise higher than anyone along a given shore area has ever seen, however . [Model of an East Coast tsunami ]
56. How much of the Earth's land surface is desert?
About one-third.
57. What's the deepest place in the ocean?
The greatest known depth is 36,198 feet (6.9 miles or 11 kilometers) at the Mariana Trench, in the Pacific Ocean well south of Japan near the Mariana Islands.
58. What is the fastest surface wind ever recorded?
The fastest "regular" wind that's widely agreed upon was 231 mph (372 kph), recorded at Mount Washington, New Hampshire, on April 12, 1934. But during a May 1999 tornado in Oklahoma, researchers clocked the wind at 318 mph (513 kph). For comparison, Neptune's winds can rage to 900 mph (1,448 kph).
59. How much fresh water is stored in the Earth?
More than two million cubic miles of fresh water is stored in the planet, nearly half of it within a half-mile of the surface. Mars, too, appears to have a lot of water near its surface, but what's been detected so far is locked up as ice; nobody has estimated how much might be there.
60. How old is Earth?
Our planet is more than 4.5 billion years old, just a shade younger than the Sun. Recent evidence actually shows that Earth was formed much earlier than previously believed, just 10 million years after the birth of the Sun, a stellar event typically put at 4.6 billion years ago.
61. What is the world's largest desert?
The Sahara Desert in northern Africa is more than 23 times the size of southern California's Mojave Desert. [Several readers have e-mailed to suggest that arid Antarctica technically tops this category; true, some researchers put it there, but most lists of deserts don't include it.]
62. Which planet has more moons, Earth or Mars?
Mars has two satellites, Phobos and Deimos. The Earth has only one natural satellite, but it's the Moon. The outer planets have lots of Moon, most of them found fairly recently and leading to the possibility that scientists might one day need to redefine what it means to be a moon.
63. What is the world's deepest lake?
Lake Baikal in the south central part of Siberia is 5,712 feet (1.7 kilometers) deep. It's about 20 million years old and contains 20 percent of Earth's fresh liquid water.
64. What is the origin of the word "volcano"?
It derives from Vulcan, the Roman god of fire.
65. How many minerals are known to exist?
There are roughly 4,000 known minerals, although only about 200 are of major importance. Approximately 50-100 new minerals are described each year.
66. What is the total water supply of the world?
The total water supply of the world is 326 million cubic miles (1 cubic mile of water equals more than 1 trillion gallons).
67. What is the world's largest island?
Greenland covers 840,000 square miles (2,176,000 square kilometers). Continents are typically defined as landmasses made of low-density rock that essentially floats on the molten material below. Greenland fits this description, but it's only about one-third the size of Australia. Some scientists call Greenland an island, others say it's a continent.
68. Where are most of Earth's volcanoes?
The most prominent topographic feature on Earth is the immense volcanic mountain chain that encircles the planet beneath the sea -- the chain is more than 30,000 miles (48,000 kilometers) long and rises an average of 18,000 feet ( 5.5 kilometers) above the seafloor. It is called the mid-ocean ridge and is where Earth's plates spread apart as new crust bubbles up -- volcanic activity. There are more volcanoes here than on land. The spreading, however, leads to scrunching when these plates slam into the continents. The result: More volcanoes and earthquakes in places like California and Japan.
69. What volcano killed the most people?
The eruption of Tambora volcano in Indonesia in 1815 is estimated to have killed 90,000 people. Most died from starvation after the eruption, though, because of widespread crop destruction, and from water contamination and disease.
70. Were Earth and the Moon separated at birth?
Not quite. But leading theory holds that our favorite satellite was carved partly from Earth shortly after the Earth formed. A Mars-sized object slammed into our fledgling planet. The impactor was destroyed. Stuff flew everywhere and a lot of it went into orbit around Earth. The Moon gathered itself together out of the largely vaporized remains of the collision, while Earth hung in there pretty much intact.
71. How many lightning strikes occur worldwide every second?
On average, about 100. Those are just the ones that hit the ground, though. During any given minute, there are more than a thousand thunderstorms around the Earth causing some 6,000 flashes of lightning. A lot of it goes from cloud-to-cloud.
72. Are rivers alive?
Not in the traditional sense, of course. But like all living creatures, rivers have a life span. They are born, grow in size, and they age. They can even die during the span of geological time.
73. Can asteroids create islands?
Speculation has existed for decades that ancient asteroid impacts might create hot spots of volcanic activity, which could give rise to mountains that poke up through seas that didn't used to be there. There's no firm answer to this question, but a recent computer model suggested Hawaii might have been formed in this manner .
74. Is the state of Louisiana growing or shrinking?
Louisiana loses about 30 square miles (78 square kilometers) of land each year to coastal erosion, hurricanes, other natural and human causes and a thing called subsidence, which means sinking. Much of New Orleans actually sits 11 feet ( 3.4 meters) below sea level. Parts of the French quarter have sunk 2 feet in the past six decades. The city is protected by dikes, but all experts agree that storm tides from a direct hit by a major hurricane would breach the system and swamp much of the city. In 2000, the director of the U.S. Geological Survey, Chip Groat, said: "With the projected rate of subsidence, wetland loss and sea-level rise, New Orleans will likely be on the verge of extinction by this time next century."
75. How much would seas rise if the Antarctic Ice Sheet melted?
The Antarctic Ice Sheet holds nearly 90 percent of the world's ice and 70 percent of its fresh water. If the entire ice sheet were to melt, sea level would rise by nearly 220 feet, or the height of a 20-story building. Scientists know there's a melting trend underway. The United Nations has said that in a worst-case scenario -- depending on how much global air temperatures increase -- seas could jump 3 feet (1 meter) by 2100.
76. Is ice a mineral?
Yes, ice is a mineral and is formally described as such in Dana's System of Mineralogy.
77. What is the softest of all minerals?
Talc is the softest of minerals. It is commonly used to make talcum powder.
78. What is the hardest of all minerals?
The one that becomes emotionally useless after a divorce but still retains monetary value.
79. How are colors produced in fireworks?
Mineral elements taken from Earth provide the colors. Strontium yields deep reds, copper produces blue, sodium yields yellow, and iron filings and charcoal pieces produce gold sparks. Bright flashes and loud bangs come from aluminum powder.
80. Does Earth have the worst weather in the solar system?
Right now, it's the worst that most humans I know ever experience. But there's lots of wilder weather elsewhere. Mars can whip up hurricane-like storms four times bigger than Texas. Dust storms on the red planet can obscure the entire globe! Jupiter has a hurricane twice the size our entire planet, and it's lasted for at least three centuries ( another storm on Jupiter is even bigger). Venus is a living hell, and Pluto is routinely more frigid than the coldest place on Earth (though may change one day, and Pluto may in fact become the last oasis for life).
81. Where are the highest tides?
In Burntcoat Head, Minas Basin, part of the Bay of Fundy in Nova Scotia, tides can range 38.4 feet (11.7 meters). The bay is funnel shaped -- its bottom slopes upward continuously from the ocean inlet. The result is an extreme "tidal bore," a wave-like phenomenon at the leading edge of the changing tide. Bores in Fundy can travel up feeder rivers at 8 mph (13 kph) and be more than 3 feet (1 meter) tall.
82. Where is the world's only equatorial glacier?
Mt. Cotopaxi in Ecuador supports the only glacier on the equator.
83. What is the largest lake in North America?
Lake Superior.
84. What's the deadliest hurricane to ever hit the United States?
A Category 4 hurricane hit Galveston, Texas in 1900 and killed more than 6,000 people (read about the history of it here). The next closest death toll was less than 1,900 from a 1928 Florida hurricane.
85. What is the longest mountain chain on Earth?
The Mid-Atlantic Ridge, which splits nearly the entire Atlantic Ocean north to south. Iceland is one place where this submarine mountain chain rises above the sea surface.
86. How much gold has been discovered worldwide to date?
More than 193,000 metric tons (425 million pounds). If you stuck it all together, it would make a cube-shaped, seven-story structure that might resemble one of Donald Trump's buildings. First you'd have to find all those rings that have gone down the drain.
87. What are the two major gold-producing countries?
South Africa produces 5,300 metric tons per year, and the United States produces more than 3,200 metric tons.
88. What North American plant can live for thousands of years?
The creosote bush, which grows in the Mojave, Sonoran, and Chihuahuan deserts, has been shown by radiocarbon dating to have lived since the birth of Christ. Some of these plants may endure 10,000 years, scientists say. If only they could talk.
89. On average, how much water is used worldwide each day?
About 400 billion gallons.
90. Is Saturn the only ringed planet?
Saturn has the most obvious rings. But Jupiter and Neptune both have subtle ring systems, [as does Uranus, readers reminded me]. And even Earth may once have been a ringed planet, the result of some space rock's glancing blow.
91. Where are the highest tides?
In Burntcoat Head, Minas Basin, part of the Bay of Fundy in Nova Scotia, tides can range 38.4 feet (11.7 meters). The bay is funnel shaped -- its bottom slopes upward continuously from the ocean inlet. The result is an extreme "tidal bore," a wave-like phenomenon at the leading edge of the changing tide. Bores in Fundy can travel up feeder rivers at 8 mph (13 kph) and be more than 3 feet (1 meter) tall.
92. Where is the world's only equatorial glacier?
Mt. Cotopaxi in Ecuador supports the only glacier on the equator.
93. What is the largest lake in North America?
Lake Superior.
94. What's the deadliest hurricane to ever hit the United States?
A Category 4 hurricane hit Galveston, Texas in 1900 and killed more than 6,000 people (read about the history of it here). The next closest death toll was less than 1,900 from a 1928 Florida hurricane.
95. What is the longest mountain chain on Earth?
The Mid-Atlantic Ridge, which splits nearly the entire Atlantic Ocean north to south. Iceland is one place where this submarine mountain chain rises above the sea surface.
96. How much gold has been discovered worldwide to date?
More than 193,000 metric tons (425 million pounds). If you stuck it all together, it would make a cube-shaped, seven-story structure that might resemble one of Donald Trump's buildings. First you'd have to find all those rings that have gone down the drain.
97. What are the two major gold-producing countries?
South Africa produces 5,300 metric tons per year, and the United States produces more than 3,200 metric tons.
98. What North American plant can live for thousands of years?
The creosote bush, which grows in the Mojave, Sonoran, and Chihuahuan deserts, has been shown by radiocarbon dating to have lived since the birth of Christ. Some of these plants may endure 10,000 years, scientists say. If only they could talk.
99. On average, how much water is used worldwide each day?
About 400 billion gallons.
100. Is Saturn the only ringed planet?
Saturn has the most obvious rings. But Jupiter and Neptune both have subtle ring systems, [as does Uranus, readers reminded me]. And even Earth may once have been a ringed planet, the result of some space rock's glancing blow.
1 The Purest Form Of Iron Is Wrought Iron
2 Leaves Change Colour In Autumn Due To Shortage Of
Chlorophyll
3 Tuberculosis Is A Disease Of Lungs Caused By Bacteria
4 The Green Leaves Of The Trees Turn Brown And Fall In Autumn
Because The Pedical Of Leaves Is Weaken Beacause Of Deficiency
Of Starch
5 The Fungi Causes Maximium Spoilage To Out Cereal Crops
6 A True Fruit Is Drived From The Ovary Of Flower
7 Blood Cells Are Manufactured By Bone Morrow Of The Body
8 W.shockly Invented Transistor
9 Microphone Is Invention Of Berliner
10 Dr Charles Invented Laser
11 Udometer:it Is A Rain Gauge,used To Measure Rain Water
12 When A Bullet Penetrates Into A Target,the Kinetic Energy Of
The Bullet Is Converted Into Mechanical Energy
13 Watson And Crick Discovered D.n.a
14 Bicycle Is Invention Of Macmillon
15 Conversion Of Milk Into Curd Is Done By Lactic Acid And Bacteria
16 Sometimes When White Blood Corpuscles Greatly Increase In
Number They Cause A Disease Called Leukemia
17 The Age Of Tree Is Determined By By Counting Its Rings
18 The Velocity Of Light Is More Than The Velocity Of Sound That
Is Why We Hear Thunder After,and See Flash Of Light First
19 The Scientific Study Of Old Age Is Called Gerontology
20 Chlorofloro Carbons Cause Decomposition Of Ozone Laye
UNIVERSE
PLANET - ATTRIBUTE - MOON - ATMOSPHERE - REVOLUTIONARY PERIOD
Mercury (58 ml km) - Smallest - No - No - 88 -
Venus - Hottest - No - CO2 - 225
Earth – dia 12756 km, rad 6400 km - Colorful - 1 - N2,O2, argon, CO2,Neon, Helium, Methane, H2 - 365.25
Mars - Red - 2 - Dark cloudy, H2 & Helium - 687
Jupitar - Biggest/Heaviest, - shortest day - 61 - H2 and Helium - 11.86yr
Saturn - Brightest - 23 - Rings of ice & dust - 29.46yr
Uranus - Green due to Methane layer, - hottest, longest day - 15 - H2 and Helium - 84.01yrs
Neptune (5900 m km far) - Blue due to Methane layer - 2 - H2 and Helium - 164.8yrs
absorptiometer instrument for measuring solubility of gases in liquids
accelerometer instrument for measuring acceleration or vibrations
acetimeter instrument for measuring strength of vinegar
acidimeter instrument for measuring concentration of acids
actinograph instrument used to calculate time of photographic exposure
actinometer instrument for measuring incident radiation
aerometer instrument for measuring weight or density of gas
aethrioscope instrument for measuring temperature variations due to sky conditions
alcoholometer instrument for measuring proportion of alcohol in solutions
alcovinometer instrument to measure strength of wine
algometer instrument for measuring sensitivity to pain
alkalimeter instrument for measuring strength of alkalines
altimeter instrument for measuring altitude
ammeter instrument for measuring electrical current
anemograph instrument for measuring pressure and velocity of wind
anemometer instrument for measuring wind velocity
areometer instrument used for measuring specific gravity
arthroscope instrument for examining interior of a joint
atmometer instrument for measuring evaporating capacity of air
audiometer instrument for measuring acuity of hearing
auriscope instrument for examining the ear
auxanometer instrument for measuring growth of plants
auxometer instrument for measuring magnifying power
ballistocardiograph instrument for detecting body movements caused by heartbeat
barograph instrument for recording air pressure
barometer instrument for measuring air pressure
baroscope weather-glass
bathymeter instrument for recording contours of deep oceans
bathythermograph instrument for recording water temperature as compared to depth
bolometer instrument for measuring radiant energy or infrared light
bronchoscope instrument for examining the windpipe
calorimeter instrument for measuring absorbed or evolved heat
cardiograph instrument for recording movements of the heart
cathetometer instrument for measuring short vertical distances
ceilometer instrument for measuring height of cloud ceiling above earth
ceraunograph instrument for recording thunder and lightning
chlorometer instrument for measuring amount of chlorine in a solution
chromatograph instrument for performing chromatographic separations
chromatoptometer instrument measuring eyes' sensitivity to colour
chronograph instrument for recording the moment of an event
chronometer instrument for measuring time
chronoscope instrument for measuring very short time intervals
clinometer instrument used to measure slopes and elevations
coercimeter instrument for measuring coercive force
colonoscope instrument for viewing the colon
colorimeter instrument for measuring and determining color
colposcope instrument for viewing the neck of the uterus
coronagraph instrument for viewing the corona of the sun
coulombmeter instrument for measuring electric charge
coulometer instrument measuring amount of substance released in electrolysis
craniometer instrument for measuring the skull
cratometer instrument for measuring power of magnification
crescograph instrument for measuring the growth of plants
cryometer instrument for measuring low temperatures
cryoscope instrument for determining freezing points of substances
cyanometer instrument for measuring blueness of the sky or ocean
cyclograph instrument for describing arcs of circles without compasses
cyclometer instrument for measuring revolutions of a wheel
cymograph instrument for tracing the outline of mouldings
cymometer instrument for measuring frequency of electrical waves
cystoscope instrument for examining the bladder
cytometer instrument for counting cells
decelerometer instrument for measuring deceleration
declinometer instrument for measuring magnetic declination
dendrometer instrument for measuring trees
densimeter instrument for measuring closeness of grain of a substance
densitometer instrument for measuring optical or photographic density
diagometer instrument for measuring electrical conductivity
diagraph instrument for enlarging or projecting drawings
diaphanometer instrument for measuring the transparency of air
dichroscope instrument for examining crystals for dichroism
diffractometer instrument for determining structure of crystal through light diffraction
dilatometer instrument for measuring expansion
dioptometer instrument for measuring focus or refraction of the eyes
dipleidoscope instrument for measuring moment when an object passes a meridian
diplograph instrument for writing two lines of text at once
dosimeter instrument for measuring dose of radiation
dromometer instrument for measuring speed
drosometer instrument for measuring dew
durometer instrument for measuring hardness of substances
dynamograph instrument for recording mechanical forces
dynamometer instrument for measuring mechanical force
ebullioscope instrument for measuring boiling point of liquids
effusiometer instrument for comparing molecular weights of gases
eidograph instrument for copying drawings
elatrometer instrument for measuring gaseous pressure
electrocardiograph instrument for recording unusual electrical fluctuations of the heart
electrodynamometer instrument for measuring electrical current
electroencephalograph instrument for measuring the brain's electrical impulses
electrograph instrument for recording electrical potential
electrometer instrument for measuring electrical potential
electromyograph instrument for diagnosing neuromuscular disorders
electroretinograph instrument for measuring electrical activity in the retina
electroscope instrument for detecting electrical charges in the body
ellipsograph instrument for describing ellipses
encephalograph instrument for recording brain images
endoscope instrument for visualizing interior of a hollow organ
endosmometer instrument for measuring osmosis into a solution
epidiascope instrument for projecting images of objects
episcope instrument for projecting images of opaque objects
ergograph instrument for measuring and recording muscular work
ergometer instrument for measuring work performed
eriometer instrument for measuring very small diameters
eudiometer instrument for measuring air purity
evaporimeter instrument for measuring rate of evaporation
extensometer instrument for measuring deformation in object due to forces applied
fathometer instrument for measuring underwater depth using sound
fiberscope instrument using fiberoptics to examine inaccessible areas
floriscope instrument for inspecting flowers
flowmeter instrument for measuring properties of flowing liquids
fluorimeter instrument for measuring fluorescence
fluoroscope instrument using x-rays to examine internal structure of opaque object
focimeter instrument for measuring focal length of a lens
galactometer instrument for measuring specific gravity of milk
galvanometer instrument for measuring electrical current
galvanoscope instrument for detecting presence and direction of electric current
gasometer instrument for holding and measuring gases
gastroscope instrument for examining interior of the stomach
geothermometer instrument for measuring subterranean temperatures
goniometer instrument for measuring angles between faces
gradiometer instrument for measuring gradient of a physical quantity
gravimeter instrument for measuring variations in gravitational fields
gyrograph instrument for counting a wheel's revolutions
haptometer instrument measuring sensitivity to touch
harmonograph instrument drawing curves representing vibrations
harmonometer instrument measuring harmonic relations of sounds
helicograph instrument for drawing spirals on a plane
heliograph instrument for measuring intensity of sunlight
heliometer instrument for measuring apparent diameter of the sun
helioscope instrument for observing sun without injury to the eyes
hemacytometer instrument for counting blood cells
hippometer instrument to measure height of horses
hodoscope instrument for tracing paths of ionizing particles
hydrometer instrument for measuring specific gravity of liquids
hydroscope instrument for viewing under water
hydrotimeter instrument for measuring water hardness
hyetograph instrument for recording rainfall
hyetometer instrument for measuring rainfall
hyetometrograph instrument for recording rainfall
hygrograph instrument for recording variations in atmospheric humidity
hygrometer instrument for measuring air moisture
hygroscope instrument for displaying changes in air humidity
hypsometer instrument for measuring height of trees through triangulation
iconometer instrument for finding size of object by measuring its image
idiometer instrument for measuring motion of observer in relation to transit of the heavens
inclinometer instrument for measuring inclination to the horizontal of an axis
interferometer instrument for analysing spectra of light
iriscope instrument for exhibiting the prismatic colours
katathermometer instrument for measuring the cooling power of air
katharometer instrument measuring changes in composition of gases
keratometer instrument for measuring curvature of the cornea
keraunograph instrument for recording distant thunderstorms
kinetoscope instrument for producing curves by combination of circular movements
konimeter instrument measuring amount of dust in air
koniscope instrument for measuring dust in air
kymograph instrument for recording fluid pressure
labidometer instrument for measuring size of the head of a fetus
lactometer instrument for testing relative density of milk
lactoscope instrument for measuring purity or richness of milk
lanameter instrument for measuring quality of wool
laparoscope instrument for viewing interior of peritoneal cavity
laryngoscope instrument for examining interior of the larynx
leptometer instrument for measuring oil viscosity
loxodograph device used to record ship's travels
lucimeter instrument for measuring light intensity
luxmeter instrument for measuring illumination
lysimeter instrument for measuring percolation of water through soil
magnetograph instrument for recording measurements of magnetic fields
magnetometer instrument for measuring intensity of magnetic fields
manometer instrument for measuring pressure of a liquid or gas
marigraph instrument for recording tide levels
mecometer instrument for measuring length
megameter instrument for determining longitude by observing stars
megascope instrument for projecting an enlarged image
mekometer range-finder
meldometer instrument for measuring melting points of substances
meteorograph instrument recording a variety of meteorological observations
methanometer instrument for detecting presence of methane
microbarograph instrument for recording minute changes in atmospheric pressure
microcalorimeter instrument for measuring tiny quantities of heat
micrograph instrument used to write on a very small scale
micrometer instrument for measuring very small distances
micronometer instrument for measuring short periods of time
microscope instrument for magnifying small objects
microseismograph instrument for recording small or distant earthquakes
microseismometer instrument for measuring small or distant earthquakes
mileometer instrument for recording distance travelled in miles
milliammeter instrument for recording very small electrical currents
myograph instrument for recording muscular contractions
myringoscope instrument for viewing the eardrum
nephelometer instrument for measuring cloudiness
nephograph instrument for photographing clouds
nephoscope instrument for observing direction and velocity of clouds
nitrometer instrument for measuring nitrogen and its compounds
odograph odometer; instrument for measuring distance travelled
odometer instrument for measuring distance travelled
odontograph instrument for obtaining curves for gear-teeth
oenometer instrument for measuring alcoholic strength of wine
ohmmeter instrument for measuring electrical resistance
oleometer instrument for measuring amount of oil in a substance
olfactometer instrument measuring intensity of odour of a substance
ombrometer rain-gauge
oncometer instrument measuring change in size of internal organs
oncosimeter instrument measuring variations in density of molten metal
ondograph instrument measuring change in wave formations of electricity
oometer instrument for measuring eggs
opacimeter instrument for measuring opacity
opeidoscope instrument for illustrating sound by means of light
ophthalmometer instrument for measuring the eye
ophthalmoscope instrument for viewing the interior of the eye
opisometer instrument for measuring curved lines
opsiometer instrument for testing vision
optometer instrument for testing vision
orchidometer instrument for measuring the size of the testicles
oscillograph instrument for recording alternating current wave forms
oscillometer instrument for measuring ship's rollings
oscilloscope instrument for detecting electrical fluctuations
osmometer instrument for measuring osmotic pressure
otoscope instrument for examining the ear
pachymeter instrument for measuring small thicknesses
pallograph instrument measuring ship's vibration
pantochronometer combined sundial and compass
pantograph instrument for copying drawing to a different scale
passimeter instrument for issuing automatic tickets
pedometer instrument for measuring distance travelled on foot
peirameter instrument measuring resistance of road surfaces to wheel movement
pelvimeter instrument for measuring the pelvis
penetrometer instrument for measuring firmness or consistency of substances
permeameter instrument for measuring permeability
phacometer instrument for measuring lenses
phaometer old instrument for measuring light intensity
pharmacometer instrument for measuring drugs
pharyngoscope instrument for inspecting the pharynx
phonautograph instrument for recording sound vibrations
phonendoscope device which amplifies small sounds
phonometer instrument for measuring sound levels
phorometer instrument used to correct abnormalities in eye muscles
photometer instrument for measuring light intensity
photopolarimeter instrument for measuring intensity and polarization of reflected light
phototachometer instrument for measuring the speed of light
phototelegraph instrument for transmitting drawings telegraphically
phthongometer instrument measuring intensity of vowel sounds
piezometer instrument for measuring pressure or compressibility
pitchometer instrument for measuring angles of ship's propeller blades
planigraph instrument for copying drawings at a different scale
planimeter instrument for measuring area of plane figures
platometer instrument for measuring area; planimeter
plegometer instrument for measuring the strength of a blow
plemyrameter instrument for measuring variations in water level
plethysmograph instrument for measuring change in body part size due to blood flow
pluviograph self-registering rain gauge
pluviometer rain-meter
pneometer instrument that measures respiration
pneumatometer instrument for measuring quantity of air breathed
pneumograph instrument for measuring and recording respiration
polarimeter instrument for measuring polarised light
polariscope instrument for detecting polarized light
polygraph instrument for measuring small changes in pulse and respiration
porometer instrument for measuring degree of porosity
poroscope instrument for investigating porosity
potentiometer instrument for measuring electromotive forces
potometer instrument measuring rate at which plants absorb water
prisoptometer instrument for measuring degree of astigmatism
proctoscope instrument for examining the rectum
psophometer instrument measuring audible interference of electrical current
psychograph instrument that supposedly records spirit messages
psychrometer instrument for measuring air moisture or temperature
psychrometer instrument for measuring dryness of the atmosphere
pulsimeter instrument for measuring the pulse
pycnometer instrument for measuring specific gravity or density
pyknometer instrument for measuring specific gravities
pyranometer instrument measuring solar radiation from the sky's whole hemisphere
pyrgeometer instrument for measuring radiation from earth
pyrheliometer instrument for measuring heating effect of sun
pyrometer instrument for measuring very high temperatures
pyroscope instrument for measuring intensity of radiant heat
qualimeter apparatus for measuring penetrating power of X-ray beams
quantimeter apparatus for measuring quantity of X-rays
quantometer instrument for measuring proportions of elements in metallic samples
rachiometer instrument for measuring the spine
radarscope instrument for detecting radar signals
radiogoniometer instrument for finding direction through radio signals
radiometeorograph instrument for measuring atmospheric conditions at high altitude
radiometer instrument measuring radiation energy
radioscope instrument for viewing objects using X-rays
ratemeter instrument for measuring counting rate of electronic counters
recipiangle old instrument with two arms used for measuring angles
reflectometer instrument for measuring reflectance of radiant energy
refractometer instrument measuring refraction of light
respirometer instrument for measuring and studying respiration
retinoscope instrument for measuring and viewing the retina
rheometer instrument that measures current
rhinoscope instrument for examining the nose
rhythmometer instrument for measuring speed of rhythms
riometer instrument for measuring absorbed cosmic radio waves
rotameter old instrument for measuring length of curved lines
rotameter instrument consisting of glass tube with free float for measuring liquid flow
saccharimeter instrument for measuring amount of sugar in a solution
salinometer instrument for measuring amount of salt in a solution
scintillometer instrument measuring scintillation of star
scintilloscope instrument for measuring gamma rays emitted by a radioactive body
sclerometer instrument measuring hardness
scoliometer instrument measuring curvature
scotograph instrument for writing without seeing
scotoscope instrument for detecting objects in darkness
seismograph instrument for recording earthquakes
seismometer instrument for measuring earthquake intensity
seismoscope instrument for detecting earthquakes
selenoscope instrument for viewing the moon
sensitometer instrument for measuring sensitivity of photographic material
sepometer instrument for measuring septic matter in the air
serimeter instrument for testing quality of silk
shuftiscope instrument used to explore interior of dysentery case
siccimeter instrument for measuring liquid evaporation
sideroscope instrument using magnets to detect presence of iron
sigmoidoscope instrument for examining the interior of the rectum and sigmoid colon
sillometer instrument measuring speed of ship
skiascope instrument for measuring eye's refraction from movement of shadows
snooperscope instrument for viewing infrared radiation
solarimeter instrument for measuring solar radiation
sonograph instrument for recording and analysing sound
spectrofluorimeter instrument for measuring and recording fluorescence spectra
spectrograph instrument for viewing a spectrum
spectroheliograph instrument for taking pictures of the sun
spectroheliokinematograph camera for taking pictures of the sun
spectrohelioscope instrument for viewing solar disc in light of a single wavelength
spectrometer instrument measuring wavelengths of light of a spectrum
spectrophotometer instrument for measuring speed of different parts of light spectrum
spectroscope instrument for forming spectra by dispersing rays of light
speedometer instrument for measuring velocity
spherometer instrument measuring curvature
sphygmograph instrument for recording pulse
sphygmomanometer instrument for measuring arterial blood pressure
sphygmometer instrument for measuring arterial blood pressure
sphygmoscope instrument for making arterial pulsations visible
spinthariscope instrument for visually detecting alpha particles
spirograph instrument recording movements of breathing
spirometer instrument measuring lung capacity
stactometer pipette with hollow bulb for counting drops
stadiometer instrument for measuring the length of a curved line
stagmometer instrument for measuring number of drops in volume of liquid
stalagmometer instrument for measuring surface tension by drops
statoscope instrument for measuring small changes in atmospheric pressure
stauroscope instrument for studying structure of crystals with polarised light
stenometer instrument for measuring distances
stereometer instrument for measuring specific gravity
stereoscope instrument for viewing special three-dimensional photographs
stethometer instrument measuring chest expansion during breathing
stethoscope instrument for detecting sounds produced by the body
strabismometer instrument measuring degree of squinting
strabometer instrument for measuring strabismus in the eyes
stroboscope instrument for studying motion using flashes of light
stylometer instrument for measuring columns
swingometer instrument for measuring swing in votes during an election
sympiesometer instrument for measuring pressure of a current
synchroscope instrument for detecting whether two moving parts are synchronized
tacheometer instrument for rapidly measuring survey points on a map
tachistoscope instrument for rapidly showing images on a screen to test perception
tachograph instrument for recording speed of rotation
tachometer instrument for measuring speed of rotation
taseometer instrument for measuring stress in a structure
tasimeter instrument for measuring changes in pressure
taximeter instrument for measuring fee for hired vehicle
telemeter instrument for measuring strain or distance from observer
telescope instrument for viewing objects at great distances
telespectroscope instrument for analysing radiation omitted by distant bodies
telestereoscope instrument for viewing distant objects stereoscopically
tellurometer instrument using microwaves to measure distance
tenderometer instrument for measuring tenderness of fruits and vegetables
tensimeter instrument for measuring vapour pressure
tensiometer instrument for measuring tension
thalassometer instrument for measuring tides
thermograph instrument for recording changes in temperature
thermometer instrument for measuring temperature
thermometrograph instrument for recording changes in temperature
thermoscope instrument indicating change in temperature
thoracoscope instrument for viewing the thorax and chest wall
tiltmeter instrument for measuring tilting of earth's surface
tocodynamometer instrument for measuring uterine contractions during childbirth
tomograph instrument for viewing section of an object using X-rays
tonometer instrument measuring pitch of musical tones
topophone instrument to determine direction and distance of a fog-horn
torsiograph instrument for recording torsional vibrations on an object
transmissometer instrument for measuring transmission of light through a fluid
trechometer instrument for determining distance travelled; odometer
tremograph instrument for recording involuntary muscular motion
tribometer instrument measuring friction
trigonometer instrument for solving triangles
trocheameter instrument counting wheel's revolutions
tromometer instrument for measuring slight earthquake shocks
tropometer instrument measuring rotation
turbidimeter instrument for measuring turbidity of liquids
turgometer instrument for measuring turgidity
typhlograph instrument to help the blind write clearly
udometer instrument for measuring rainfall
ultramicroscope instrument for viewing extremely small objects
urethroscope instrument for viewing the interior of the urethra
urinometer instrument for measuring specific gravity of urine
vaporimeter instrument for measuring vapour pressure
variometer instrument for measuring magnetic declination
velocimeter instrument for measuring velocity
velometer instrument for measuring speed of air
viameter instrument for measuring revolutions of a wheel
vibrograph instrument for recording vibrations
vibrometer instrument for measuring vibrations
viscometer instrument for measuring viscosity
visometer instrument for measuring focal length of the eye
voltameter instrument for measuring electrical current indirectly
voltmeter instrument for measuring electrical potential
volumenometer instrument for measuring volume of a solid
volumeter instrument for measuring volume of a liquid or gas
wattmeter instrument for measuring electrical power
wavemeter instrument for measuring wavelengths
weatherometer instrument for measuring weather-resisting properties of paint
xanthometer instrument for measuring colour of sea or lake water
xylometer instrument measuring specific gravity of wood
zymometer instrument for measuring fermentation
zymosimeter instrument for measuring fermentation
Annealing is a heat treatment wherein a material is altered, causing changes in its properties such as strength and hardness. Annealing is used to induce ductility, soften material, relieve internal stresses, refine the structure by making it homogeneous, and improve cold working properties.
Electroplating is a plating process in which metal ions, in a solution, are moved by an electric field to coat an electrode. Electroplating is primarily used for depositing a layer of material to bestow a desired property (e.g., abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.) to a surface that otherwise lacks that property.
Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting.
Vulcanization is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur or other equivalent "curatives." A vast array of products is made with vulcanized rubber including tires, shoe soles, hoses, and hockey pucks.
Gestation period, for mammals, is the time in which a fetus develops, beginning with fertilization and ending at birth.[1] The duration of this period varies between species.
Brass gets discoloured in air because of the presence of which of the following gases in air?
A. Oxygen
B. Hydrogen sulphide
C. Carbon dioxide
D. Nitrogen
Which of the following is a non metal that remains liquid at room temperature?
A. Phosphorous
B. Bromine
C. Chlorine
D. Helium
Chlorophyll is a naturally occurring chelate compound in which central metal is
A. copper
B. magnesium
C. iron
D. calcium
Which of the following is used in pencils?
A. Graphite
B. Silicon
C. Charcoal
D. Phosphorous
Which of the following metals forms an amalgam with other metals?
A. Tin
B. Mercury
C. Lead
D. Zinc
Chemical formula for water is
A. NaA1O2
B. H2O
C. Al2O3
D. CaSiO3
The gas usually filled in the electric bulb is
A. nitrogen
B. hydrogen
C. carbon dioxide
D. oxygen
Washing soda is the common name for
A. Sodium carbonate
B. Calcium bicarbonate
C. Sodium bicarbonate
D. Calcium carbonate
Quartz crystals normally used in quartz clocks etc. is chemically
A. silicon dioxide
B. germanium oxide
C. a mixture of germanium oxide and silicon dioxide
D. sodium silicate
Which of the gas is not known as green house gas?
A. Methane
B. Nitrous oxide
C. Carbon dioxide
D. Hydrogen
Our Solar System
Our solar neighborhood is an exciting place. The Solar System is full of planets, moons, asteroids, comets, minor planets, and many other exciting objects. Learn about Io, the explosive moon that orbits the planet Jupiter, or explore the gigantic canyons and deserts on Mars.
What Is The Solar System?
The Solar System is made up of all the planets that orbit our Sun. In addition to planets, the Solar System also consists of moons, comets, asteroids, minor planets, and dust and gas.
Everything in the Solar System orbits or revolves around the Sun. The Sun contains around 98% of all the material in the Solar System. The larger an object is, the more gravity it has. Because the Sun is so large, its powerful gravity attracts all the other objects in the Solar System towards it. At the same time, these objects, which are moving very rapidly, try to fly away from the Sun, outward into the emptiness of outer space. The result of the planets trying to fly away, at the same time that the Sun is trying to pull them inward is that they become trapped half-way in between. Balanced between flying towards the Sun, and escaping into space, they spend eternity orbiting around their parent star.
How Did The Solar System form?
This is an important question, and one that is difficult for scientists to understand. After all, the creation of our Solar System took place billions of years before there were any people around to witness it. Our own evolution is tied closely to the evolution of the Solar System. Thus, without understanding from where the Solar System came from, it is difficult to comprehend how mankind came to be.
Scientists believe that the Solar System evolved from a giant cloud of dust and gas. They believe that this dust and gas began to collapse under the weight of its own gravity. As it did so, the matter contained within this could begin moving in a giant circle, much like the water in a drain moves around the center of the drain in a circle.
At the center of this spinning cloud, a small star began to form. This star grew larger and larger as it collected more and more of the dust and gas that collapsed into it.
Further away from the center of this mass where the star was forming, there were smaller clumps of dust and gas that were also collapsing. The star in the center eventually ignited forming our Sun, while the smaller clumps became the planets, minor planets, moons, comets, and asteroids.
A Great Storm
Once ignited, the Sun's powerful solar winds began to blow. These winds, which are made up of atomic particles being blown outward from the Sun, slowly pushed the remaining gas and dust out of the Solar System.
With no more gas or dust, the planets, minor planets, moons, comets, and asteroids stopped growing. You may have noticed that the four inner planets are much smaller than the four outer planets. Why is that?
Because the inner planets are much closer to the Sun, they are located where the solar winds are stronger. As a result, the dust and gas from the inner Solar System was blown away much more quickly than it was from the outer Solar System. This gave the planets of the inner Solar System less time to grow.
Another important difference is that the outer planets are largely made of gas and water, while the inner planets are made up almost entirely of rock and dust. This is also a result of the solar winds. As the outer planets grew larger, their gravity had time to accumulate massive amounts of gas, water, as well as dust.
The Solar System Has Over 100 Worlds
It is true that there are only eight planets. However, the Solar System is made up of over 100 worlds that are every bit as fascinating. Some of these minor planets, and moons are actually larger than the planet Mercury!
Others, such as Io, have active volcanoes. Europa has a liquid water ocean, while Titan has lakes, rivers, and oceans of liquid Methane. You can read more about these amazing worlds by clicking here.
The Asteroid Belt, The Kuiper Belt, And The Oort Cloud
You have probably heard about the Asteroid Belt. This band of asteroids sits between the orbits of the planets Jupiter and Mars. It is made up of thousands of objects too small to be considered planets. Some of them no larger than a grain of dust, while others, like Eros can be more than 100 miles across. A few, like Ida, even have their own moons.
Further out, beyond the orbit of the minor planet Pluto, sits another belt known as the Kuiper Belt. Like the Asteroid Belt, the Kuiper Belt is also made up of thousands, possibly even millions of objects too small to be considered planets. A few of these objects, like Pluto, are large enough that their gravity has pulled them into a sphere shape.
These objects are made out of mostly frozen gas with small amounts of dust. They are often called dirty snowballs. However, you probably know them by their other name... comets.
Every once in a while one of these comets will be thrown off of its orbit in the Kuiper Belt and hurled towards the inner Solar System Where it slowly melts in a fantastic show of tail and light.
Beyond the Kuiper Belt sits a vast area known as the Oort Cloud. Here within this jumbled disorganized cloud live millions of additional comets. These comets do not orbit the Sun in a ring or belt. Instead, each one buzzes around in a completely random direction, and at extremely high velocities.
Beyond The Oort Cloud
The Sun's solar winds continue pushing outward until they finally begin to mix into the interstellar medium, becoming lost with the winds from other stars. This creates a sort of bubble called the Heliosphere. Scientists define the boundaries of the Solar System as being the border of the Heliosphere, or at the place where the solar winds from the Sun mix with the winds from other stars.
The Heliosphere extends out from the Sun to a distance of about 15 billion miles, which is more than 160 times further from the Sun than is the Earth.
What are asteroids?
An asteroid is a large rock in outer space. Some, like Ceres, can be very large, while others are as small as a grain of sand. Due to their smaller size, asteroids do not have enough gravity to pull themselves into the shape of a ball. Astronomers group asteroids into different categories based on the way they reflect sunlight.
The asteroid belt is divided into an inner belt and an outer belt. The inner belt which is made up of asteroids that are within 250 million miles (402 million km) of the Sun, contains asteroids that are made of metals.
The outer belt, which includes asteroids 250 million miles (402 million km) beyond the Sun, consists of rocky asteroids. These asteroids appear darker than the asteroids of the inner belt, and are rich in carbon.
Where did the Asteroid Belt come from?
Asteroids are left over materials from the formation of the Solar System. These materials were never incorporated into a planet because of their proximity to Jupiter's strong gravity.
Comets
Among the most brilliant and most rare objects in the night sky. These soaring beacons with their beautiful tails come from the outer realms of the Solar System.
What are comets?
A comet is a small world which scientists sometimes call a planetesimal. They are made out of dust and ice, kind of like a dirty snow ball.
Where do they come from?
Comets come from two places: The Kuiper Belt and the Oort Cloud.
Many people think that a comet's tail is always following behind it, but actually the coma, or tail, can either be behind the comet or in front of it. Which way the tail is pointing depends on where the Sun is. That's right, the Sun's heat and radiation produce a wind called the Solar Wind, as a comet gets close to the Sun it begins to melt. The gas and dust that melt off are blown away from the Sun by the solar winds. So if a comet is traveling towards the Sun then the tail will follow behind, but if the comet is traveling away from the Sun the tail will be in front of the comet.
Imagine a place far, far away at the very edge of the Solar System. A place where millions of comets can be seen swishing around in every direction. These icy comets are orbiting the Sun in two different places, both of which are very distant. One place is called the Oort cloud, and the other is called the Kuiper Belt.
Why do Comets leave their home in the Oort Cloud or Kuiper Belt?
A comet will spend billions of years in the Kuiper Belt or Oort Cloud. Sometimes two comets will come very close to each other, or even crash into one another. When this happens the comets change directions. Sometimes their new path will bring them into the Inner Solar System.
This is when a comet begins to shine. Up until now the comet has been among millions of others exactly the same, but as they approach the warmer Inner Solar System they begin to melt leaving behind magnificent tails.
Unfortunately, comets don't live very long once they enter the warmer part of the Solar System. Just like a snowman melts in the summer, comets melt in the Inner Solar System. Although it is the most glorious part of their lives, traveling through the Inner Solar System eventually kills them. After several thousand years they melt down to a little bit of ice and dust, not nearly enough to leave a tail. Some even melt away completely.
Would it be safe to fly through the tail of a comet?
Unlike a recent blockbuster movie showing a space ship flying past giant rocks the size of houses, a comet's tail is actually quite safe. The only thing that would hit your ship would be microscopic pieces of dust.
The Sun's Name Means:
The Romans called the sun Sol, which in English means sun. In ancient Greece, the sun was called Helios.
Our Sun is not unique in the universe. It is a common middle-sized yellow star which scientists have named Sol, after the ancient Roman name. This is why our system of planets is called the Solar System. There are trillions of other stars in the universe just like it. Many of these stars have their own systems of planets, moons, asteroids, and comets.
The Sun was born in a vast cloud of gas and dust around 5 billion years ago. Indeed, these vast nebulae are the birth places of all stars. Over a period of many millions of years, this gas and dust began to fall into a common center under the force of its own gravity.
At the center, an ever growing body of mass was forming. As the matter fell inward, it generated a tremendous amount of heat and pressure. As it grew, the baby Sun became hotter and hotter. Eventually, when it reached a temperature of around 1 million degrees, its core ignited, causing it to begin nuclear fusion.
When this happened, the Sun began producing its own light, heat, and energy.
What is Thermonuclear Fusion?
Thermonuclear fusion is the process in which a star produce its light, heat, and energy. This happens at the core of the star. The core is superheated to millions of degrees. This heat travels towards the surface and radiates out into the universe. Through this thermonuclear process, stars "burn" a fuel known as hydrogen. The result is that they create another type of fuel known as helium. However, stars do not burn in the same way that a fire does, because stars are not on fire.
Convection
Heat rises, while cooler gas falls. Have you ever noticed that your basement is always much cooler than upstairs. The same laws of physics apply within stars. Because heat rises while cooler gases fall, the gas within a star is constantly rising and falling. This creates massive streams of circular motion within the star. This is called convection.
As the gases near the core of the Sun are heated, they begin to rise towards the surface. As they do so, they cool somewhat. Eventually they become cool enough that they begin to sink back down towards the core. It can take an atom millions of years to complete one complete cycle around a convection stream. As a result of this process, the temperature on the surface of the Sun is around 10,000 degrees Fahrenheit, which is much cooler than its superheated core.
Sun Spots
We don't often think of the Sun as having cooler areas on its surface. The Sun is far too hot for an astronaut to ever visit, but there are areas which are slightly cooler than others. These areas are known as sun spots. Sun spots are still very hot. However, because they are slightly cooler than the rest of the surface of the Sun, they appear slightly darker in color. The gravitational forces in Sun spots are also stronger than the other hotter areas. Of course, you cannot look directly at the Sun to see these spots because you would damage your eyes. Astronomers have to use special telescopes with filters and other instruments to be able to see the cooler spots on the surface of the Sun.
Sun spots come and go on a regular basis. At times, there are very few, if any sun spots. At other times there are far more. They generally increase in intensity and then decrease over a period of 11 years. This 11 year cycle is known as the Saros Cycle.
Solar Flares
During periods of high solar activity, the Sun commonly releases massive amounts of gas and plasma into its atmosphere. These ejections are known as solar flares. Some solar flares can be truly massive, and contain impressive power. On occasion, these more powerful flares can even cause satellites orbiting the Earth to malfunction. They can also interact with Earth's magnetic field to create impressive and beautiful light shows known as the Northern and Southern lights. In the northern hemisphere, these lights are commonly known as the Aurora Borealis.
Solar Winds
As the Sun burns hydrogen at its core, it releases vast amounts of atomic particles, or pieces of atoms, into outer space. These atomic particles along with the Sun's radiation create a sort of wind, known as the solar wind.
This wind blows particles outward in all directions from the Sun. Even as you read this, there are atomic particles which are traveling from the Sun towards you. Often, particles pass right through your body without you ever realizing it.
Eventually this wind reaches out beyond the Solar System and begins to mix with the winds from other stars. The bubble around the Sun where the solar winds are still strong enough to blow outward is known as the heliosphere (note the Greek name Helios). The area of space where the winds are too weak to continue pushing outward and instead begin to mix with the winds of other stars is known as the interstellar medium.
The Sun's Family
The Sun is by far the largest object in the Solar System. 98% of all matter within the Solar System is found within the Sun. This means that all the planets, moons, asteroids, minor planets, comets, gas, and dust would all combine to make up only 2% of all the matter in the Solar System. The Sun is so large that the Earth could easily fit inside the Sun a million times.
Because the Sun is so large compared to everything else, it is easily able to hold on to the rest of the matter, causing everything else to orbit around it.
Do you know
Light from the Sun can reach the Earth in only 8 minutes! This is called the speed of light. The Sun is nearly 93 million miles (approx 145 million km) from Earth.
Earth means:
In astronomy mythology, her Greek name was Gaea. Earth was the mother of the mountains, valleys, streams and all other land formations. She was married to Uranus
How Big is the Earth?
The Earth is the biggest of all the terrestrial planets. A terrestrial planet is a dense planet found in the inner Solar System. The diameter of Earth is 7,926 miles. The circumference measured around the equator is 24,901 miles. There are currently almost 7 billion people living on the Earth. About 30% of the Earth's surface is covered with land, while about 70% is covered by oceans.
The Planet
Our planet is an oasis of life in an otherwise desolate universe. The Earth's temperature, weather, atmosphere and many other factors are just right to keep us alive.
Moons:
The Earth has one moon. Its name is Luna.
Our solar neighborhood is an exciting place. The Solar System is full of planets, moons, asteroids, comets, minor planets, and many other exciting objects. Learn about Io, the explosive moon that orbits the planet Jupiter, or explore the gigantic canyons and deserts on Mars.
What Is The Solar System?
The Solar System is made up of all the planets that orbit our Sun. In addition to planets, the Solar System also consists of moons, comets, asteroids, minor planets, and dust and gas.
Everything in the Solar System orbits or revolves around the Sun. The Sun contains around 98% of all the material in the Solar System. The larger an object is, the more gravity it has. Because the Sun is so large, its powerful gravity attracts all the other objects in the Solar System towards it. At the same time, these objects, which are moving very rapidly, try to fly away from the Sun, outward into the emptiness of outer space. The result of the planets trying to fly away, at the same time that the Sun is trying to pull them inward is that they become trapped half-way in between. Balanced between flying towards the Sun, and escaping into space, they spend eternity orbiting around their parent star.
How Did The Solar System form?
This is an important question, and one that is difficult for scientists to understand. After all, the creation of our Solar System took place billions of years before there were any people around to witness it. Our own evolution is tied closely to the evolution of the Solar System. Thus, without understanding from where the Solar System came from, it is difficult to comprehend how mankind came to be.
Scientists believe that the Solar System evolved from a giant cloud of dust and gas. They believe that this dust and gas began to collapse under the weight of its own gravity. As it did so, the matter contained within this could begin moving in a giant circle, much like the water in a drain moves around the center of the drain in a circle.
At the center of this spinning cloud, a small star began to form. This star grew larger and larger as it collected more and more of the dust and gas that collapsed into it.
Further away from the center of this mass where the star was forming, there were smaller clumps of dust and gas that were also collapsing. The star in the center eventually ignited forming our Sun, while the smaller clumps became the planets, minor planets, moons, comets, and asteroids.
A Great Storm
Once ignited, the Sun's powerful solar winds began to blow. These winds, which are made up of atomic particles being blown outward from the Sun, slowly pushed the remaining gas and dust out of the Solar System.
With no more gas or dust, the planets, minor planets, moons, comets, and asteroids stopped growing. You may have noticed that the four inner planets are much smaller than the four outer planets. Why is that?
Because the inner planets are much closer to the Sun, they are located where the solar winds are stronger. As a result, the dust and gas from the inner Solar System was blown away much more quickly than it was from the outer Solar System. This gave the planets of the inner Solar System less time to grow.
Another important difference is that the outer planets are largely made of gas and water, while the inner planets are made up almost entirely of rock and dust. This is also a result of the solar winds. As the outer planets grew larger, their gravity had time to accumulate massive amounts of gas, water, as well as dust.
The Solar System Has Over 100 Worlds
It is true that there are only eight planets. However, the Solar System is made up of over 100 worlds that are every bit as fascinating. Some of these minor planets, and moons are actually larger than the planet Mercury!
Others, such as Io, have active volcanoes. Europa has a liquid water ocean, while Titan has lakes, rivers, and oceans of liquid Methane. You can read more about these amazing worlds by clicking here.
The Asteroid Belt, The Kuiper Belt, And The Oort Cloud
You have probably heard about the Asteroid Belt. This band of asteroids sits between the orbits of the planets Jupiter and Mars. It is made up of thousands of objects too small to be considered planets. Some of them no larger than a grain of dust, while others, like Eros can be more than 100 miles across. A few, like Ida, even have their own moons.
Further out, beyond the orbit of the minor planet Pluto, sits another belt known as the Kuiper Belt. Like the Asteroid Belt, the Kuiper Belt is also made up of thousands, possibly even millions of objects too small to be considered planets. A few of these objects, like Pluto, are large enough that their gravity has pulled them into a sphere shape.
These objects are made out of mostly frozen gas with small amounts of dust. They are often called dirty snowballs. However, you probably know them by their other name... comets.
Every once in a while one of these comets will be thrown off of its orbit in the Kuiper Belt and hurled towards the inner Solar System Where it slowly melts in a fantastic show of tail and light.
Beyond the Kuiper Belt sits a vast area known as the Oort Cloud. Here within this jumbled disorganized cloud live millions of additional comets. These comets do not orbit the Sun in a ring or belt. Instead, each one buzzes around in a completely random direction, and at extremely high velocities.
Beyond The Oort Cloud
The Sun's solar winds continue pushing outward until they finally begin to mix into the interstellar medium, becoming lost with the winds from other stars. This creates a sort of bubble called the Heliosphere. Scientists define the boundaries of the Solar System as being the border of the Heliosphere, or at the place where the solar winds from the Sun mix with the winds from other stars.
The Heliosphere extends out from the Sun to a distance of about 15 billion miles, which is more than 160 times further from the Sun than is the Earth.
What are asteroids?
An asteroid is a large rock in outer space. Some, like Ceres, can be very large, while others are as small as a grain of sand. Due to their smaller size, asteroids do not have enough gravity to pull themselves into the shape of a ball. Astronomers group asteroids into different categories based on the way they reflect sunlight.
The asteroid belt is divided into an inner belt and an outer belt. The inner belt which is made up of asteroids that are within 250 million miles (402 million km) of the Sun, contains asteroids that are made of metals.
The outer belt, which includes asteroids 250 million miles (402 million km) beyond the Sun, consists of rocky asteroids. These asteroids appear darker than the asteroids of the inner belt, and are rich in carbon.
Where did the Asteroid Belt come from?
Asteroids are left over materials from the formation of the Solar System. These materials were never incorporated into a planet because of their proximity to Jupiter's strong gravity.
Comets
Among the most brilliant and most rare objects in the night sky. These soaring beacons with their beautiful tails come from the outer realms of the Solar System.
What are comets?
A comet is a small world which scientists sometimes call a planetesimal. They are made out of dust and ice, kind of like a dirty snow ball.
Where do they come from?
Comets come from two places: The Kuiper Belt and the Oort Cloud.
Many people think that a comet's tail is always following behind it, but actually the coma, or tail, can either be behind the comet or in front of it. Which way the tail is pointing depends on where the Sun is. That's right, the Sun's heat and radiation produce a wind called the Solar Wind, as a comet gets close to the Sun it begins to melt. The gas and dust that melt off are blown away from the Sun by the solar winds. So if a comet is traveling towards the Sun then the tail will follow behind, but if the comet is traveling away from the Sun the tail will be in front of the comet.
Imagine a place far, far away at the very edge of the Solar System. A place where millions of comets can be seen swishing around in every direction. These icy comets are orbiting the Sun in two different places, both of which are very distant. One place is called the Oort cloud, and the other is called the Kuiper Belt.
Why do Comets leave their home in the Oort Cloud or Kuiper Belt?
A comet will spend billions of years in the Kuiper Belt or Oort Cloud. Sometimes two comets will come very close to each other, or even crash into one another. When this happens the comets change directions. Sometimes their new path will bring them into the Inner Solar System.
This is when a comet begins to shine. Up until now the comet has been among millions of others exactly the same, but as they approach the warmer Inner Solar System they begin to melt leaving behind magnificent tails.
Unfortunately, comets don't live very long once they enter the warmer part of the Solar System. Just like a snowman melts in the summer, comets melt in the Inner Solar System. Although it is the most glorious part of their lives, traveling through the Inner Solar System eventually kills them. After several thousand years they melt down to a little bit of ice and dust, not nearly enough to leave a tail. Some even melt away completely.
Would it be safe to fly through the tail of a comet?
Unlike a recent blockbuster movie showing a space ship flying past giant rocks the size of houses, a comet's tail is actually quite safe. The only thing that would hit your ship would be microscopic pieces of dust.
The Sun's Name Means:
The Romans called the sun Sol, which in English means sun. In ancient Greece, the sun was called Helios.
Our Sun is not unique in the universe. It is a common middle-sized yellow star which scientists have named Sol, after the ancient Roman name. This is why our system of planets is called the Solar System. There are trillions of other stars in the universe just like it. Many of these stars have their own systems of planets, moons, asteroids, and comets.
The Sun was born in a vast cloud of gas and dust around 5 billion years ago. Indeed, these vast nebulae are the birth places of all stars. Over a period of many millions of years, this gas and dust began to fall into a common center under the force of its own gravity.
At the center, an ever growing body of mass was forming. As the matter fell inward, it generated a tremendous amount of heat and pressure. As it grew, the baby Sun became hotter and hotter. Eventually, when it reached a temperature of around 1 million degrees, its core ignited, causing it to begin nuclear fusion.
When this happened, the Sun began producing its own light, heat, and energy.
What is Thermonuclear Fusion?
Thermonuclear fusion is the process in which a star produce its light, heat, and energy. This happens at the core of the star. The core is superheated to millions of degrees. This heat travels towards the surface and radiates out into the universe. Through this thermonuclear process, stars "burn" a fuel known as hydrogen. The result is that they create another type of fuel known as helium. However, stars do not burn in the same way that a fire does, because stars are not on fire.
Convection
Heat rises, while cooler gas falls. Have you ever noticed that your basement is always much cooler than upstairs. The same laws of physics apply within stars. Because heat rises while cooler gases fall, the gas within a star is constantly rising and falling. This creates massive streams of circular motion within the star. This is called convection.
As the gases near the core of the Sun are heated, they begin to rise towards the surface. As they do so, they cool somewhat. Eventually they become cool enough that they begin to sink back down towards the core. It can take an atom millions of years to complete one complete cycle around a convection stream. As a result of this process, the temperature on the surface of the Sun is around 10,000 degrees Fahrenheit, which is much cooler than its superheated core.
Sun Spots
We don't often think of the Sun as having cooler areas on its surface. The Sun is far too hot for an astronaut to ever visit, but there are areas which are slightly cooler than others. These areas are known as sun spots. Sun spots are still very hot. However, because they are slightly cooler than the rest of the surface of the Sun, they appear slightly darker in color. The gravitational forces in Sun spots are also stronger than the other hotter areas. Of course, you cannot look directly at the Sun to see these spots because you would damage your eyes. Astronomers have to use special telescopes with filters and other instruments to be able to see the cooler spots on the surface of the Sun.
Sun spots come and go on a regular basis. At times, there are very few, if any sun spots. At other times there are far more. They generally increase in intensity and then decrease over a period of 11 years. This 11 year cycle is known as the Saros Cycle.
Solar Flares
During periods of high solar activity, the Sun commonly releases massive amounts of gas and plasma into its atmosphere. These ejections are known as solar flares. Some solar flares can be truly massive, and contain impressive power. On occasion, these more powerful flares can even cause satellites orbiting the Earth to malfunction. They can also interact with Earth's magnetic field to create impressive and beautiful light shows known as the Northern and Southern lights. In the northern hemisphere, these lights are commonly known as the Aurora Borealis.
Solar Winds
As the Sun burns hydrogen at its core, it releases vast amounts of atomic particles, or pieces of atoms, into outer space. These atomic particles along with the Sun's radiation create a sort of wind, known as the solar wind.
This wind blows particles outward in all directions from the Sun. Even as you read this, there are atomic particles which are traveling from the Sun towards you. Often, particles pass right through your body without you ever realizing it.
Eventually this wind reaches out beyond the Solar System and begins to mix with the winds from other stars. The bubble around the Sun where the solar winds are still strong enough to blow outward is known as the heliosphere (note the Greek name Helios). The area of space where the winds are too weak to continue pushing outward and instead begin to mix with the winds of other stars is known as the interstellar medium.
The Sun's Family
The Sun is by far the largest object in the Solar System. 98% of all matter within the Solar System is found within the Sun. This means that all the planets, moons, asteroids, minor planets, comets, gas, and dust would all combine to make up only 2% of all the matter in the Solar System. The Sun is so large that the Earth could easily fit inside the Sun a million times.
Because the Sun is so large compared to everything else, it is easily able to hold on to the rest of the matter, causing everything else to orbit around it.
Do you know
Light from the Sun can reach the Earth in only 8 minutes! This is called the speed of light. The Sun is nearly 93 million miles (approx 145 million km) from Earth.
Earth means:
In astronomy mythology, her Greek name was Gaea. Earth was the mother of the mountains, valleys, streams and all other land formations. She was married to Uranus
How Big is the Earth?
The Earth is the biggest of all the terrestrial planets. A terrestrial planet is a dense planet found in the inner Solar System. The diameter of Earth is 7,926 miles. The circumference measured around the equator is 24,901 miles. There are currently almost 7 billion people living on the Earth. About 30% of the Earth's surface is covered with land, while about 70% is covered by oceans.
The Planet
Our planet is an oasis of life in an otherwise desolate universe. The Earth's temperature, weather, atmosphere and many other factors are just right to keep us alive.
Moons:
The Earth has one moon. Its name is Luna.
Abbreviations:
From Past Papers
From Past Papers
1. LPG: Liquefied Petroleum Gas
2. TNT: Tri Nitro Toluene
3. RNA: Ribonucleic Acid
4. CNG: Compressed Natural Gas
5. ATP: Adenosine Tri Phosphate
6. RBC: Red Blood Cells/Corpuscles
7. ECG: Electro Cardio Gram
8. PVC: Poly vinyl Chloride
9. RAM: Random Access Memory
10. CFC: Chloro Fluoro Carbon
11. LASER: Light Amplification by Stimulated emission of Radiation
12. RADAR: Radio Detection And Ranging
13. AIDS: Acquired Immune Deficiency Syndrome
14. ROM: Read Only Memory
15. LAN: Local Area Network
16. WWW: World Wide Web
17. DNA: Deoxyribonucleic Acid
18. SONAR: Sound Navigation And Ranging
19. SARS: Severe Acute Respiratory Syndrome
20. NTP: Network Time Protocol/ Normal Temperature and Pressure
21. RQ: Respiratory Quotient
22. NPN: Negative Positive Negative/
23. PNP: Purine Nucleoside Phosphorylase
24. WAN: Wide Area Network
25. CPU: Central Processing Unit
26. BCG: Bacillus Calmette Guerin
27. STP: Standard Temperature And Pressure/Shielded Twisted Pair/Sodium Tripolyphosphate/Spanning Tree Protocol
28. ATP: Adenosine Triphosphate
29. KWh: Kilo Watt Hour
30. BTU: British thermal Unit
31. LDL: Low Density Lipoprotein
32. MAF: Million Acre Feet
33. HDL: Hardware Description Language
34. MCV: Mean Corpuscular Volume
35. UHF: Ultra High Frequency
36. LED: Light emitting Diode
37. LCD: Liquid Crystal Display
38. BASIC: Beginner’s All-Purpose Symbolic Instruction Code
39. MASER: Microwave Amplification by Stimulated Emission of Radiation
40. ETT: Educational Telecommunications and Technology/ European Transaction on Telecommunication
41. HST: High Speed Technology/ High Speed Train (in UK)/Hubble Space Telescope
42. DBS: Data Base Server/ Direct Broadcast Satellite
43. CRO: Cathode Ray Oscilloscope
44. BOT: Build, Operate and Transfer/Botulinum Toxin
45. AMU: Atomic Mass Unit
46. EMF: Electro Motive force
47. ADH: Anti-diuretic Hormone
48. GeV: Giga Electro Volt
49. CRT: Cathode Ray Tube
50. CNS: Central Nervous System
51. PTFE: Poly Tetra Fluoro Ethylene
52. GUT: Grand Unified Theory
53. LONAR: Long Range Navigation
54. MeV: Mega Electron Volt/ Million Electron Volt/ Multi-experiment Viewer
55. AWACS: Airborne Warning and Control System
56. CCTV: Closed-Circuit Television
1. ABM: Anti-Ballistic Missile
2. AC: Alternating Current/Air Conditioning
3. AEC: Atomic Energy Commission
4. Alt: Altitude
5. am: Ante Maridiem (Before Noon/Midday)
6. Amp: Ampere
7. APTEC: All Pakistan Technology Engineers Council
8. ATM: Automated Teller Machine (Banking)
9. AW: Atomic Weight/ Asia Watch
10. BIOS: Basic Input Output System
11. BDS: Bachelor Of Dental Surgery/ Bomb Disposal Squad
12. BP: Blood Pressure/ Boiling Point/ Blue Print
13. C/A: Current Account
14. CAA: Civil Aviation Authority
15. CABB: Centre Of Agricultural Biochemistry And Biotechnology
16. CAD: Computer-Aided Design
17. Cal: Calorie
18. CD: Compact Disc/ Civil Defence/ Community Development
19. CD-ROM: Compact Disc Read-Only Memory
20. CECP: Cotton Export Corporation Of Pakistan
21. CHASNUPP: Chashma Nuclear Power Plant
22. CMCC: China Mobile Communications Corporation
23. COM: Computer Aided Manufacturing
24. COMSAT: Communications Satellite Corporation
25. COMSTECH: Council Of Scientific And Technology Cooperation Of Islamic Conference
26. CSIRO: Commonwealth Scientific And Industrial Research Organisation
27. CTBT: Comprehensive Test Ban Treaty
28. CT-Scan: Computerised Axial Tomography Scanning
29. DVD: Dynamic Versatile Disc
30. ECAT: Engineering Colleges Admission Test
31. EDB: Engineering Development Board
32. EEG: Electroencephalogram
33. ENERCON: Energy Conservation Centre
34. EPA: Energy Protection Agency
35. EPD: Energy Protection Department
36. ESA: European Space Agency
37. ESRO: European Space Research Organisation
38. FAT: File Allocation Table
39. FCPS: Fellow Of The Royal College Of Physicians And Surgeons
40. FM: Frequency Modulation
41. FMCT: Fissile Material Cut-Off Treaty
42. FRCS: Fellow Of The Royal College Of Surgeons
43. GHz. Gigahertz
44. GMT: Greenwich Mean Time
45. HIV: Human Immune Deficiency Virus
46. HTML: Hypertext Mark-Up Language
47. HTTP: Hypertext Transfer Protocol
48. IAEA:International Atomic Energy Agency (UN)
49. IBM: International Business Machine
50. IC: Integrated Circuit/ Intelligence Corps
51. ICBM: Inter-Continental Ballistic Missile
52. ICU: Intensive Care Unit
53. IEA: International Energy Agency
54. INSTRAW: International Research And Training Institute For The Advancement Of Women
55. INTELSAC: International Telecommunications Satellite Consortium
56. Intelsat: International Telecommunications Satellite Organisation
57. IRBM: Intermediate Range ballistic Missile
58. ISP: Internet Service Provider
59. IT: Information Technology
60. ITB: Information Technology Board
61. JAXA: Japan Aerospace Exploration Agency
62. KANUPP: Karachi Nuclear Power Plant
63. KAPCO: Kot Adu Power Company
64. kHz: Kilohertz
65. KV: Kilo Volt
66. kW: Kilowatt
67. MCAT: Medical Colleges Admission Test
68. MDS: Master In Dental Surgery
69. MNP: Mobile Number Probability
70. MRBM: Medium Range Ballistic Missile
71. MRCP: Member Of Royal College Of Physicians
72. MRCS: Member Of Royal College Of Surgeons
73. MRI: Magnetic Resonance Imaging
74. MS: Medical Superintendent
75. MSN: Microsoft Network
76. MW: Megawatt
77. NADRA: National Database And Registration Authority
78. NEPRA: National Electric Power Regulatory Authority
79. NM: Nautical Mile
80. NMD: National Missile Defence
81. NPT: Non-Nuclear Proliferation Treaty
82. NRA: Nuclear Regulatory Authority
83. OGRA: Oil And Gas Regulatory Authority
84. NWD: Nation Wide Dialling
85. OGDC: Oil And Gas Development Corporation
86. pm: Post Meridiem
87. PEMRA: Pakistan Electronic Media Regulatory Authority
88. PTA: Pakistan Telecommunication Authority
89. RADAR: Radio Detection and Ranging
90. SALT: Strategic Arms Limitation Talks
91. SLV: Satellite Launch Vehicle
92. SMS: Short Message Service
93. SNGPL: Sui Northern Gas Pipelines Limited
94. SONAR: Sound Navigation And Ranging
95. SSGPL: Sui Southern Gas Pipeline Limited
96. STD: Subscriber’s Trunk Dialling
97. STM: Subscriber Identification
98. SUPARCO: Space And Upper Atmosphere Research Committee (Pakistan)
99. TB: Tubercle Bacillus/ Tuberculosis
100. UHF: Ultra High Frequency
2. AC: Alternating Current/Air Conditioning
3. AEC: Atomic Energy Commission
4. Alt: Altitude
5. am: Ante Maridiem (Before Noon/Midday)
6. Amp: Ampere
7. APTEC: All Pakistan Technology Engineers Council
8. ATM: Automated Teller Machine (Banking)
9. AW: Atomic Weight/ Asia Watch
10. BIOS: Basic Input Output System
11. BDS: Bachelor Of Dental Surgery/ Bomb Disposal Squad
12. BP: Blood Pressure/ Boiling Point/ Blue Print
13. C/A: Current Account
14. CAA: Civil Aviation Authority
15. CABB: Centre Of Agricultural Biochemistry And Biotechnology
16. CAD: Computer-Aided Design
17. Cal: Calorie
18. CD: Compact Disc/ Civil Defence/ Community Development
19. CD-ROM: Compact Disc Read-Only Memory
20. CECP: Cotton Export Corporation Of Pakistan
21. CHASNUPP: Chashma Nuclear Power Plant
22. CMCC: China Mobile Communications Corporation
23. COM: Computer Aided Manufacturing
24. COMSAT: Communications Satellite Corporation
25. COMSTECH: Council Of Scientific And Technology Cooperation Of Islamic Conference
26. CSIRO: Commonwealth Scientific And Industrial Research Organisation
27. CTBT: Comprehensive Test Ban Treaty
28. CT-Scan: Computerised Axial Tomography Scanning
29. DVD: Dynamic Versatile Disc
30. ECAT: Engineering Colleges Admission Test
31. EDB: Engineering Development Board
32. EEG: Electroencephalogram
33. ENERCON: Energy Conservation Centre
34. EPA: Energy Protection Agency
35. EPD: Energy Protection Department
36. ESA: European Space Agency
37. ESRO: European Space Research Organisation
38. FAT: File Allocation Table
39. FCPS: Fellow Of The Royal College Of Physicians And Surgeons
40. FM: Frequency Modulation
41. FMCT: Fissile Material Cut-Off Treaty
42. FRCS: Fellow Of The Royal College Of Surgeons
43. GHz. Gigahertz
44. GMT: Greenwich Mean Time
45. HIV: Human Immune Deficiency Virus
46. HTML: Hypertext Mark-Up Language
47. HTTP: Hypertext Transfer Protocol
48. IAEA:International Atomic Energy Agency (UN)
49. IBM: International Business Machine
50. IC: Integrated Circuit/ Intelligence Corps
51. ICBM: Inter-Continental Ballistic Missile
52. ICU: Intensive Care Unit
53. IEA: International Energy Agency
54. INSTRAW: International Research And Training Institute For The Advancement Of Women
55. INTELSAC: International Telecommunications Satellite Consortium
56. Intelsat: International Telecommunications Satellite Organisation
57. IRBM: Intermediate Range ballistic Missile
58. ISP: Internet Service Provider
59. IT: Information Technology
60. ITB: Information Technology Board
61. JAXA: Japan Aerospace Exploration Agency
62. KANUPP: Karachi Nuclear Power Plant
63. KAPCO: Kot Adu Power Company
64. kHz: Kilohertz
65. KV: Kilo Volt
66. kW: Kilowatt
67. MCAT: Medical Colleges Admission Test
68. MDS: Master In Dental Surgery
69. MNP: Mobile Number Probability
70. MRBM: Medium Range Ballistic Missile
71. MRCP: Member Of Royal College Of Physicians
72. MRCS: Member Of Royal College Of Surgeons
73. MRI: Magnetic Resonance Imaging
74. MS: Medical Superintendent
75. MSN: Microsoft Network
76. MW: Megawatt
77. NADRA: National Database And Registration Authority
78. NEPRA: National Electric Power Regulatory Authority
79. NM: Nautical Mile
80. NMD: National Missile Defence
81. NPT: Non-Nuclear Proliferation Treaty
82. NRA: Nuclear Regulatory Authority
83. OGRA: Oil And Gas Regulatory Authority
84. NWD: Nation Wide Dialling
85. OGDC: Oil And Gas Development Corporation
86. pm: Post Meridiem
87. PEMRA: Pakistan Electronic Media Regulatory Authority
88. PTA: Pakistan Telecommunication Authority
89. RADAR: Radio Detection and Ranging
90. SALT: Strategic Arms Limitation Talks
91. SLV: Satellite Launch Vehicle
92. SMS: Short Message Service
93. SNGPL: Sui Northern Gas Pipelines Limited
94. SONAR: Sound Navigation And Ranging
95. SSGPL: Sui Southern Gas Pipeline Limited
96. STD: Subscriber’s Trunk Dialling
97. STM: Subscriber Identification
98. SUPARCO: Space And Upper Atmosphere Research Committee (Pakistan)
99. TB: Tubercle Bacillus/ Tuberculosis
100. UHF: Ultra High Frequency
101. UNAEC: United Nations Atomic Energy Commission
102. UNESCO: United Nations Education, Scientific And Cultural Organisation
103. VCD: Video Compact Disc
104. VHF: Very High Frequency
105. WAN: Wide Area Network
106. WAP: Wireless Application Protocol
107. WAPDA: Water And Power Development Authority
108. WHO: World Health Organisation
109. WMD: Weapons Of Mass Destruction
110. WWF: World Wildlife Fund
111. ZETA: Zero Energy Thermo-Nuclear Assembly
112. ZPG: Zero Population Growth
102. UNESCO: United Nations Education, Scientific And Cultural Organisation
103. VCD: Video Compact Disc
104. VHF: Very High Frequency
105. WAN: Wide Area Network
106. WAP: Wireless Application Protocol
107. WAPDA: Water And Power Development Authority
108. WHO: World Health Organisation
109. WMD: Weapons Of Mass Destruction
110. WWF: World Wildlife Fund
111. ZETA: Zero Energy Thermo-Nuclear Assembly
112. ZPG: Zero Population Growth
UNITS:
From Past Papers:
From Past Papers:
1. Force: Newton/ Dyne
2. Temperature: Kelvin/ Celsius/ Degree
3. Current: Ampere
4. Heat: Joule/ Calorie/ BTU
5. Pressure: Pascal/Torr
6. Radioactivity: Becquerel/Curie/Rutherford
7. Atomic energy: Rydberg/Joule
8. Voltage: Volt
9. Electric Potential Difference: Volt
10. Electric Charge: Coulomb
11. Power: Watt
12. Resistance: Ohm
13. Conductivity: Mho
14. Energy: Joule/ Erg
15. Distance Between Stars And Planets: Light Year
16. Wavelength: Angstrom
17. Volume: Acre-Foot/Litre
18. Frequency: Hertz
19. Rate of flow of water: Cusec
20. Length: Meter/Fermi/Parsec
21. Optical Power Of A Lens or A Curved Mirror: Dioptre
22. Plane Angle: Radian
23. Luminous Intensity: Candela
24. Amount of Substance: Mole
25. Rate Of Decay Of Radioactive Material: Rutherford
26. Sedimentation Rate: SVEDBERG Unit
27. Induction: Henry
28. Magnetic flux: Maxwell/ Weber
29. Magnetic Flux Density/Magnetic Inductivity: Telsa/Gauss
30. Electric Conductance: Siemens
31. Angle: Degree
32. Solid Angle: Steradian
33. Torque: Foot-Pound
34. Mass: Slug
35. Volume of Water Reservoirs: Acre-foot
36. Mechanical work/Energy: Erg
37. Magneto Motive Force: Gilbert
39. Dyne: Force
40. Kelvin: Temperature
41. Celsius: Temperature
42. Degree: Temperature
43. Ampere: Current
44. Joule: Heat/Atomic Energy/Energy
45. Calorie: Heat
46. BTU: Heat
47. Pascal: Pressure
48. Torr: Pressure
49. Becquerel: Radioactivity
50. Curie: Radioactivity
51. Rutherford: Rate Of Decay Of Radioactive Material/Radioactivity
52. Rydberg: Atomic Energy
53. Volt: Voltage/Electron Potential Difference
54. Coulomb: Electric Charge
55. Watt: Power
56. Ohm: Resistance
57. Mho: Conductivity
58. Erg: Energy
59. Light Year: Distance Between Stars
60. Angstrom: Wavelength
61. Litre: Volume
62. Acre Foot: Volume
63. Hertz: Frequency
64. Cusec: Rate Of Flow Of Water
65. Meter: Length
66. Fermi: Length
67. Parsec: Length
68. Dioptre: Optical Power Of Lens
69. Radian: Plane Angle
70. Candela: Luminous Intensity
71. SVEDBERG: Sedimentation Rate
72. Henry: inductance
73. Maxwell: Magnetic Flux
74. Weber: Magnetic Flux
75. Tesla: Magnetic Flux Density/Magnetic Inductivity
76. Gauss: Magnetic Flux Density/Magnetic Inductivity
77. Siemens: Electric Conductance
78. Degree: Angle
79. Steradian: Solid Angle
80. Foot Pound: torque
81. Slug: Mass
82. Erg: Mechanical Work/Energy
83. Gilbert: Magneto Motive Force
Discoveries/Inventions-Scientists
Past Papers
Past Papers
1. Structure Of DNA: Watson & Crick
2. Rabies Vaccination: Louis Pasteur
3. Penicillin: Alexander Fleming
4. Genetic Laws of Heredity: Mendel
5. Vaccination Against Small Pox: Edward Jenner
6. Solar System: Copernicus
7. Current Electricity: Volta
8. Telephone: Graham Bell
9. Gramophone: Thomas Edison
10. Atomic Number: Mosley
11. Mercury Thermometer: Fahrenheit
12. Dynamite: Alfred Noble
13. Cell: Robert Hooke
14. Television: John Baird
15. X-rays: Roentgen
16. Circulation Of Blood: William Harvey
17. Bicycle: Macmillan
18. Wireless Telegraphy: Signor Marconi
19. Microorganisms: Antoni Van Leeuwenhoek
20. Laser: Dr. C. Gilbert
21. Periodic Table: Mendeleev
22. Radium: Madam Marie Curie
23. Mass/Energy Conversion Equation: Einstein
24. Cement: Joseph Aspdin
25. Simple Microscope: Hans Janssen and Zacharias Janssen
26. Sulphuric, Nitric and Hydrochloric Acid: Jabir Bin Hayan
27. Jet Engine: Frank Whittle
28. Electricity: Thomas Edison
29. Computer: Charles Babbage
30. Lightening Conductor: Benjamin Franklin
31. Semiconductor: Bardeen and Brattain
32. Uncertainty Principle: Heisenberg
33. Cyclotron: Ernest Lawrence
34. Electro Magnetic Engine: James Maxwell
35. Internal Combustion Engine: Nikolas August Otto
36. Earth As A Huge Magnet: William Gilbert
37. First Person To Orbit Earth: Yuri Gagarin
38. Water: Henry Cavendish
39. Gravitation: Newton
40. Magnet: Dr. Gilbert
41. E.M Induction: Faraday
42. Energy Quanta: Max Planck
More Discoveries/Inventions-Scientists
43. Vitamin. C Therapy: Linus Pauling44. First Clone Of A Sheep: Ian Wilmit
45. Streptomycin: S.A.Waksman
46. Helical Structure Of Protein: Linus Pauling
47. Polio Vaccine: Jonas Salk
48. Nylon: Wallace. H Carothers
49. Radioactivity: Becquerel
50. Safety Match: John Walker
51. Gun Powder: Roger Bacon
52. Jupiter: Galileo
53. Neutron: James Chadwick
54. Earth’s Radius: Eratosthenes
55. Oxygen: Joseph Priestley
56. Noble Gases: Cavendish
57. Synthesis Of Gene In Laboratory: Hargobind Khorana
58. Earth Revolves Round The Sun: Copernicus
59. Binomial Nomenclature: Carl Von Linnaeus
60. North America: Christopher Columbus
61. Green Land: Robert Peary
62. Transistor: William Bradford Shockley
63. Typewriter: Sholes
64. Bacteriology: Pasteur
65. Laser: Theodore Maiman
66. Father Of Botany: Theophrastus
67. Father Of Zoology: Aristotle
68. Father Of Taxonomy: Carolus Linnaeus
69. Father Of Genetics: Gregor Mendel
70. Cell Theory: Scheilden And Schwann
71. Cholera Bacillus: Robert Koch
72. Theory Of Relativity And Photoelectric Effect: Einstein
73. Insulin: Dr. F.G Banting
74. Nucleus: Robert Brown
75. Chromosome: Waldeyer
76. Ultra Violet Rays: Johann Wilhelm Ritter
77. Law Of Attraction And Repulsion Between Electric Charges: Coulomb
78. Battery: Alessandro Volta
79. Electromagnetic theory: James Clerk Maxwell
80. First Person To Televise Pictures Of Moving Objects: John Logie Baird
81. Antiseptic Medicine: Joseph Lister
82. Cotton Gin: Eli Whitney
83. Big Bang Theory: Georges Lemaitre
84. Electron: J.J Thomson
85. Aeroplane: Wilbur and Orville Wright
86. Steam Railway Locomotive: Richard Trevithick
87. Radio: Marconi
88. Household Vacuum Cleaner: Herbert Cecil Booth
89. Bakelite: Baekeland
90. Windscreen Wipers: Marry Anderson
91. Ballpoint pen: Laszlo And Georg Biro
92. Helicopter: Igor Sikorsky
93. DDT: Paul Muller
94. Blood Banking: Charles Drew
95. AK-47: Mikhail Kalashnikov
96. Integrated Circuit: Robert Noyce
97. Cellular Phone: Dr. Martin Cooper
98. Vitamins: Funk
99. Uranus: Herschel
100. Calculating Machine: Blaise Pascal
101. Tuberculosis: Robert Koch
102. Logarithm Table: John Napier
103. Malaria Parasite: Ronald Ross
104. Zero: Al Khwarizmi
105. Velocity Of Light: Roomer
Physical Quantity—Instrument For Measurement:
Past Papers
1. Pressure: Barometer
2. Voltage: Voltmeter
3. Purity Of Milk: Lactometer
4. Temperature: Thermometer
5. Velocity Of Wind: Anemometer
6. Earthquake: Richter Scale
7. Degree Of Humidity: Hygrometer
8. Blood Pressure: Sphygmomanometer
9. Radioactivity: Geiger Counter
10. High Temperature: Pyrometer
11. Rainfall: Rain Guage
12. Earthquake Recording: Seismograph
13. Electric current: Ammeter
SHOTY QUESTIONS
1. Question: A man with a load jumps from a high building. What will be the load experienced by him?
Answer: Zero, because while falling, both the man and the load are falling at the same acceleration i.e. Acceleration due to gravity.
2. Question: A piece of chalk when immersed in water emits bubbles. Why?
Answer: Chalk consists of pores forming capillaries. When it is immersed in water, the water begins to rise in the capillaries and air present there is expelled in the form of bubbles.
3. Question: Why does a liquid remain hot or cold for a long time inside a thermos flask?
Answer: The presence of air, a poor conductor of heat, between the double glass wall of a thermos flask, keeps the liquid hot or cold inside a flask for a long time.
4. Question: Why does a ball bounce upon falling?
Answer: When a ball falls, it is temporarily deformed. Because of elasticity, the ball tends to regain its original shape for which it presses the ground and bounces up (Newton's Third Law of Motion).
5 Question: Why is standing in boats or double decker buses not allowed, particularly in the upper deck of buses?
Answer: On tilting the centre of gravity of the boat or bus is lowered and it is likely to overturn.
6. Question: Why is it recommended to add salt to water while boiling dal?
Answer: By addition of salt, the boiled point of water gets raised which helps in cooking the dal sooner.
7. Question: Why is it the boiling point of sea water more than that of pure water?
Answer: Sea water contains salt, and other impurities which cause an elevation in its boiling point.
8. Question: Why is it easier to spray water to which soap is added?
Answer: Addition of soap decreases the surface tension of water. The energy for spraying is directly proportional to surface tension.
9. Question: Which is more elastic, rubber or steel?
Answer: Steel is more elastic for the same stress produced compared with rubber.
10. Question: Why is the sky blue?
Answer: Violet and blue light have short waves which are scattered more than red light waves. While red light goes almost straight through the atmosphere, blue and violet light are scattered by particles in the atmosphere. Thus, we see a blue sky.
11. Question: Why Does ink leak out of partially filled pen when taken to a higheraltitude?
Answer: As we go up, the pressure and density of air goes on decreasing. A Partially filled pen leaks when taken to a higher altitude because the pressure of air acting on the ink inside the tube of the pen is greater than the pressure of the air outside.
12. Question: On the moon, willthe weightof a man be less or more than his weight on the earth?
Answer: The gravity of the moon is one-sixth that of the earth; hence the weight of a person on the surface of the moon will be one-sixth of his actual weight on earth.
13. Question: Why do some liquid burn while others do not?
Answer: A liquid burns if its molecules can combine with oxygen in the air with the production of heat. Hence, oil burns but water does not.
14. Question: Why can we see ourselves in a mirror?
Answer: We see objects when light rays from them reach our eyes. As mirrors have a shiny surface, the light rays are reflected back to us and enter our eyes.
15. Question: Why does a solid chunk of ironsinkin water but float in mercury?
Answer: Because the density of iron is more than that of water bus less than that of mercury.
16. Question: Why is cooking quicker in a pressure cooker?
Answer: As the pressure inside the cooker increases, the boiling point of water is raised, hence, the cooking process is quicker.
17. Question: When wood burns it crackles. Explain?
Answer: Wood contains a complex mixture of gases and tar forming vapors trapped under its surface. These gases and tar vapors escape, making a cracking sound.
18. Question: Why do stars twinkle?
Answer: The light from a star reaches us after refraction as it passes through various layers of air. When the light passes through the earth?S atmosphere, it is made to flicker by the hot and cold ripples of air and it appears as if the stars are twinkling.
19. Question: Why is it easier to roll a barrel than to pull it?
Answer: Because the rolling force of friction is less than the dynamic force of sliding friction.
20. Question: If a feather, a wooden ball and a steel ball fall simultaneously in a vacuum, which one of these would fall faster?
Answer: All will fall at the same speed in vacuum because there will be no air resistance and the earth?S gravity will exert a similar gravitational pull on all.
21. Question: When a man fires a gun, he is pushed back slightly. Why?
Answer: As the bullet leaves the nozzle of the gun?S barrel with momentum in a forward direction, as per Newton's Third Law of Motion, the ejection imparts to the gun as equal momentum in a backward direction.
22. Question: Ice wrapped in a blanket or saw dust does not melt quickly. Why?
Answer: Both wood and wool are bad conductors of heat. They do not permit heat rays to reach the ice easily.
23. Question: Why do we perspire on a hot day?
Answer: When the body temperature rises, the sweat glands are stimulated to secrete perspiration. It is nature's way to keep the body cool. During the process of evaporation of sweat, body heat is taken away, thus giving a sense of coolness.
24. Question: Why does ice float on water butsinkin alcohol?
Answer: Because ice is lighter than water it floats on it. However, ice is heavier than alcohol and therefore it sinks in alcohol.
25. Question: Why do we perspire before rains?
Answer: Before the rain falls, the atmosphere gets saturated with water vapors; as a result, the process of evaporation of sweat is delayed.
26. Question: Why does athermometerkept in boiling water show no change in reading after 1000C?
Answer: The boiling point of water is 1000C. Once water starts boiling at this temperature, thermometer records no change in temperature. The quantity of heat supplied is being utilized as latent heat of evaporation to convert the water at boiling point into vapour.
27. Question: Why do we bring our hands close to the mouth while shouting across to someone far away?
: By keeping hands close to mouth the sound is not allowed to spread (Phenomenon of diffraction of sound) in all direction, but is directed to a particular direction and becomes louder.
28. Question: Why does a corked bottle filled with water burst if left out on a frosty night?
Answer: Because of low temperature the water inside the bottle freezes. On freezing it expands, thereby its volume increases and pressure is exerted on the walls.
29. Question: Why is a small gap left at the joint between two rails?
Answer: To permit expansion of rails due to heat generated by friction of a moving train.
30. Question: Why cannot a copper wire be used to make elements inelectric heater?
Answer: Copper melts at 108.30C and forms a black powder on reacting with atmospheric oxygen. For heater elements a metal should have more resistance to produce heat.31. Question: Why are water or mercury droplets always round when dropped on a clean glass?
Answer: The surface of a liquid is the seat of a special force as a result of which molecules on the surface are bound together to form something like a stretched membrane. They tend to compress the molecules below to the smallest possible volume, which causes the drop to take a round shape as for a given mass he sphere has minimum volume.
32. Question: Why does a balloon filled with hydrogen rise in the air?
Answer: Weight of hydrogen is less than the weight of air displaced by it. In balloons hydrogen is normally filled because it is lighter than air.
33. Question: Why do we lean forward while climbing a hill?
Answer: In order to keeps the vertical line passing through our centre of gravity always between our feet, which is essential to attain equilibrium or stability.
34. Question: Why does smoke curl up in the air?
Answer: Smoke contains hot gases which being lighter in weight, follows a curved path because of the eddy currents that are set up in the air.
35. Question: Why does an electric bulb explode when it is broken?
Answer: The bulb encompasses partial vacuum and as it breaks, air rushes in causing a small explosion.
36. Question: Why does a man fall forward when he jumps out of a running train or bus?
Answer: He is in motion while in the train or bus. When he jumps out, his feet comes to rest while touching the ground but his upper portion which is still in motion propels him forward.
37. Question: Why does an ordinary glass tumbler crack when very hot tea or milk is poured in it?
Answer: When a hot liquid is poured into a tumbler, the inner layer of the tumbler gets heated, it expands before the outer layer and an unequal expansion of both layers causes the tumbler to crack.
38. Question: Why is a compass used as an indicator of direction?
Answer: The magnetic needles of a compass under the influence f the earth?S magnetic field lie in a north-south direction. Hence, we can identify direction.
39. Question: Why is water from a hand pump warm in winter and cold in summer? Answer: In winter, the outside temperature is lower than that of water flowing out of the pump, and therefore, the water is warm. Whereas in summer, the outside temperature is higher than the water of the pump, and therefore, it feels cold.
40. Question: Why is a rainbow seen after a shower?
Answer: After a shower, the clouds containing water droplets act like a prism through which the white light is dispersed producing a spectrum.
Question: Why does a swimming pool appear less deep than is actually is?
Answer: The rays of light coming from the bottom of the pool pass from a denser medium (water) to a rarer medium (air) and are refracted (bend away from the normal). When the rays return to the surface, they form an image of the bottom of the pool at a point, which is little above the real position.
42. Question: Why is one?S breath visible in winter but not in summer?
Answer: In winter, water vapor contained in the breath condenses into small droplets, which become visible but in summer they are quickly evaporated and not seen.
43. Question: Why doesn?T the electric filament in an electric bulb burn up?
Answer: Firstly, because is made of tungsten which has a very high melting point (34100C) whereas the temperature of the filament required to glow is only 2700oc. Secondly, oxygen is absent since the bulb is filled with an inert gas which does not help in burning.
44. Question: Why does blotting paper absorb ink?
Answer: Blotting paper has fine pores, which act like capillaries. When a portion of blotting paper is brought in contact with ink, ink enters the pores due to surface tension (capillary action f liquids) and is absorbed.
45. Question: Why does a small iron sink in water but a large ship float?
Answer: The weight of water displaced by an iron ball is less than its own weight, whereas water displaced by the immersed portion of a ship is equal to its weight (Archimedes? Principle).
46. Question: Why does ice float on water?
Answer: The weight of the ice block is equal to the weight of the liquid displaced by the immersed portion of the ice.
47. Question: Why does moisture gather outside a tumbler containing cold water?
Answer: The water vapour in the air condenses on cooling and appears as droplets of water.
48. Question: Why does kerosene float on water?
Answer: Because the density of kerosene is less than that of water. For the same reason cream rises in milk and floats at the top.
49. Question: Why is the water in an open pond cool even on a hot summer day?
Answer: As the water evaporates from the open surface of a pond, heat is taken away in the process, leaving the surface cool.
50. Question: Why is it less difficult to cook rice or potatoes at higher altitudes?
Answer: Atmospheric pressure at higher altitudes is low and boils water below 100C. The boiling point of water is directly proportional to the pressure on its surface.
51. Question: Why is it difficult to breathe at higher altitudes?
Answer: Because of low air pressure at higher altitudes the quantity of air is less, and so that of oxygen.
52. Question: Why are winter nights and summer nights warmer during cloudy weather than when the sky is clear?
Answer: Clouds being bad conductors of heat do not permit radiation of heat from land to escape into the sky. As this heat remains in the atmosphere, the cloudy nights are warmer.
53. Question: Why is a metal tyre heated before it is fixed on wooden wheels?
Answer: On heating, the metal tyre expands by which its circumference also increases. This makes fixing the wheel easier and therefore cooling down shrinks it; thus fixing the tyre tightly.
54. Question: Why is it easier to swim in the sea than in a river?
Answer: The density of sea water is higher; hence the up thrust is more than that of river water.
55. Question: Who will possibly learn swimming faster-a fat person or a thin person?
Answer: The fat person displaces more water which will help him float much more freely compared to a thin person.
56. Question: Why is a flash of lightening seen before thunder?
Answer: Because light travels faster than sound, it reaches the earth before the sound of thunder.
57. Question: Why cannot a petrol fire be extinguished by water?
Answer: Water, which is heavier than petrol, slips down permitting the petrol to rise to the surface and continue to burn. Besides, the existing temperature is so high that the water poured on the fire evaporates even before it can extinguish the fire. The latter is true if a small quantity of water is poured.
58. Question: Why does water remain cold in an earthen pot? Answer: There are pores in an earthen pot which allow water to percolate to the outer surface. Here evaporation of water takes place thereby producing a cooling effect.
59. Question: Why do we place a wet cloth on the forehead of a patient suffering from high temperature?
Answer: Because of body?S temperature, water evaporating from the wet cloth produces a cooling effect and brings the temperature down.
60. Question: When a needle is placed on a small piece of blotting paper which is place on the surface of clean water, the blotting paper sinks after a few minutes but the needle floats. However, in a soap solution the needle sinks. Why?
Answer: The surface tension of clean water being higher than that of a soap solution, it cans support the weight of a needle due to its surface tension. By addition of soap, the surface tension of water reduces, thereby resulting in the sinking of the needle.61. Question: To prevent multiplication of mosquitoes, it is recommended to sprinkle oil in the ponds with stagnant water. Why?
Answer: Mosquitoes breed in stagnant water. The larvae of mosquitoes keep floating on the surface of water due to surface tension. However, when oil is sprinkled, the surface tension is lowered resulting in drowning and death of the larvae.
62. Question: Why does oil rise on a cloth tape of an oil lamp?
Answer: The pores in the cloth tape suck oil due to the capillary action of oil.
63. Question: Why are ventilators in a room always made near the roof?
Answer: The hot air being lighter in weight tends to rise above and escape from the ventilators at the top. This allows the cool air to come in the room to take its place.
64. Question: How does ink get filled in a fountain pen?
Answer: When the rubber tube of a fountain pen immersed in ink is pressed, the air inside the tube comes out and when the pressure is released the ink rushes in to fill the air space in the tube.
65. Question: Why are air coolers less effective during the rainy season?
: During the rainy reason, the atmosphere air is saturated with moisture. Therefore, the process of evaporation of water from the moist pads of the cooler slows down thereby not cooling the air blown out from the cooler.
66. Question: Why does grass gather more dew in nights than metallic objects such as stones?
Answer: Grass being a good radiator enables water vapour in the air to condense on it. Moreover, grass gives out water constantly (transpiration) which appears in the form of dew because the air near grass is saturated with water vapour and slows evaporation. Dew is formed on objects which are good radiations and bad conductors.
67. Question: If a lighted paper is introduced in a jar of carbon dioxide, its flame extinguishes. Why?
Answer: Because carbon dioxide does not help in burning. For burning, oxygen is required.
68. Question: Why does the mass of an iron increase on rusting?
Answer: Because rust is hydrated ferric oxide which adds to the mass of the iron rod. The process of rusting involves addition of hydrogen and oxygen elements to iron.
69. Question: Why does milk curdle?
Answer: Lactose (milk sugar) content of milk undergoes fermentation and changes into lactic acid which on reacting with milk protein (casein) form curd.
70. Question: Why does hard water not lather soap profusely?
Answer: Hard water contains sulphates and chlorides of magnesium and calcium which forms an insoluble compound with soap. Therefore, soap does not lather with hard water.
71. Question: Why is it dangerous to have charcoal fire burning in a closed room?
Answer: When charcoal burns it produces carbon monoxide which is suffocating and can cause death.
72. Question: Why is it dangerous to sleep under trees at night?
Answer: Plants respire at night and give out carbon dioxide which reduces the oxygen content of air required for breathing.
73. Question: Why is a new quilt warmer than an old one?
Answer: In a new quilt the cotton is not compressed and as such it encloses more air which is bad conductor of heat. Therefore, it does not allow heat to pass.
74. Question: Curved rail tracks or curved roads are banked or raised on one side. Why?
Answer: Because a fast moving train or vehicle leans inwards while taking turn and the banked or raised track provides required centripetal force to enable it to move round the curve.
75. Question: How do bats fly in dark?
Answer: When bats fly they produce ultrasonic sound waves which are reflected back to them from the obstacles in their way and hence they can fly without difficulty.
76. Question: Water pipes often burst at hill stations on cold frosty nights. Why? Answer: The temperature may fall below 00C during cold frosty nights which converts the water inside the pipes into ice, resulting in an increase in volume. This exerts great force on the pipes and as a result, they burst.
. Question: Why are white clothes more comfortable in summer than dark or black ones?
Answer: White clothes are good reflectors and bad absorbers of heat, whereas dark or black clothes are good absorbers of heat. Therefore, white clothes are more comfortable because they do not absorb heat from the sun rays.
78. Question: Why does a rose appear red grass green in daylight?
Answer: Rose absorbs all the constituent colors of white light except red which is reflected to us. Similarly, grass absorbs all colors except green which is reflected t us.
79. Question: Why does a ship rise as it enters the sea from a river?
Answer: The density of sea water is high due to impurities and salts compared to river water as a result; the upthurst produced by the sea water on the ship is more than that of river water.
80. Question: Why are fuse provided in electric installations?
Answer: A safety fuse is made of a wire of metal having a very low melting point. When excess current flows in, the wire gets heated, melts and breaks the circuit. By breaking the circuit it saves electric equipment or installations from damage by excessive flow of current.
81. Question: Why is it easier to lift a heavy object under water than in air?
Answer: Because when a body is immersed in water, it experiences an upward thrust (Archimedes? Principle) and loses weight equal to the weight of the water displaced by its immersed potion, and hence, is easier to lift objects.
82. Question: If a highly pumped up bicycle tyre is left in the hot sunlight, it bursts. Why?
Answer: The air inside the tube increases in volume when heated up. As sufficient space for the expansion of the air is not available because the tube is already highly pumped, it may result in bursting of the tyre.
83. Question: What will be the color of green in blue light?
Answer: Grass will appear dark in color because it absorbs all other colors of the light except its own green color. The blue light falling on grass will be absorbed by it, and hence, it will appear dark in color.
84. Question: Why do two eyes give better vision than one?
Answer: Because two eyes do not form exactly similar images and he fusion of these two dissimilar images in the brain gives three dimensions of the stereoscopic vision.
1. What is the hottest place on Earth?
Count one wrong if you guessed Death Valley in California. True enough on many days. But El Azizia in Libya recorded a temperature of 136 degrees Fahrenheit (57.8 Celsius) on Sept. 13, 1922 -- the hottest ever measured. In Death Valley, it got up to 134 Fahrenheit on July 10, 1913.
2. And the coldest place around here?
Far and away, the coldest temperature ever measured on Earth was -129 Fahrenheit (-89 Celsius) at Vostok, Antarctica, on July 21, 1983.
3. What makes thunder?
If you thought, "Lightning!" then hats off to you. But I had a more illuminating answer in mind. The air around a lightning bolt is superheated to about five times the temperature of the Sun. This sudden heating causes the air to expand faster than the speed of sound, which compresses the air and forms a shock wave; we hear it as thunder.
4. Can rocks float?
In a volcanic eruption, the violent separation of gas from lava produces a "frothy" rock called pumice, loaded with gas bubbles. Some of it can float, geologists say. I've never seen this happen, and I'm thankful for that.
5. Can rocks grow?
Yes, but observing the process is less interesting than watching paint dry. Rocks called iron-manganese crusts grow on mountains under the sea. The crusts precipitate material slowly from seawater, growing about 1 millimeter every million years. Your fingernails grow about the same amount every two weeks.
6. How much space dust falls to Earth each year?
Estimates vary, but the USGS says at least 1,000 million grams, or roughly 1,000 tons of material enters the atmosphere every year and makes its way to Earths surface. One group of scientists claims microbes rain down from space, too, and that extraterrestrial organisms are responsible for flu epidemics . There's been no proof of this, and I'm not holding my breath.
7. How far does regular dust blow in the wind?
A 1999 study showed that African dust finds its way to Florida and can help push parts of the state over the prescribed air quality limit for particulate matter set by the U.S. Environmental Protection Agency. The dust is kicked up by high winds in North Africa and carried as high as 20,000 feet (6,100 meters), where it's caught up in the trade winds and carried across the sea. Dust from China makes its way to North America, too.
8. Where is the worlds highest waterfall?
The water of Angel Falls in Venezuela drops 3,212 feet (979 meters).
9. What two great American cities are destined to merge?
The San Andreas fault, which runs north-south, is slipping at a rate of about 2 inches (5 centimeters) per year, causing Los Angeles to move towards San Francisco. Scientists forecast LA will be a suburb of the City by the Bay in about 15 million years.
10. Is Earth a sphere?
Because the planet rotates and is more flexible than you might imagine, it bulges at the midsection, creating a sort of pumpkin shape. The bulge was lessening for centuries but now, suddenly, it is growing, a recent study showed. Accelerated melting of Earth's glaciers is taking the blame for the gain in equatorial girth.
11. What would a 100-pound person weigh on Mars?
The gravity on Mars is 38 percent of that found on Earth at sea level. So a 100-pound person on Earth would weigh 38 pounds on Mars. Based on NASA's present plans, it'll be decades before this assumption can be observationally proved, however.
12. How long is a Martian year?
It's a year long, if you're from Mars. To an earthling, it's nearly twice as long. The red planet takes 687 Earth-days to go around the Sun -- compared to 365 days for Earth. Taking into account Mars' different rotational time (see #13 below) calendars on Mars would be about 670 days long with some leap days needed to keep things square. If you find one, please mail it to me. I'm curious how they worked out the months, given they have two moons. [The initial publication of this fact mistakenly said a Mars calendar would have 687 days.]
13. How long is the average Martian day?
A Martian can sleep (or work) and extra half-hour every day compared to you. Mars days are 24 hours and 37 minutes long, compared to 23 hours, 56 minutes on Earth. A day on any planet in our solar system is determined by how long it takes the world to spin once on its axis, making the Sun appear to rise in the morning and sending it down in the evening.
14. What is the largest volcano?
The Mauna Loa volcano in Hawaii holds the title here on Earth. It rises more than 50,000 feet (9.5 miles or 15.2 kilometers) above its base, which sits under the surface of the sea. But that's all volcanic chump change. Olympus Mons on Mars rises 16 miles (26 kilometers) into the Martian sky. Its base would almost cover the entire state of Arizona.
15. What was the deadliest known earthquake?
The world's deadliest recorded earthquake occurred in 1557 in central China. It struck a region where most people lived in caves carved from soft rock. The dwellings collapsed, killing an estimated 830,000 people. In 1976 another deadly temblor struck Tangshan, China. More than 250,000 people were killed.
16. What was the strongest earthquake in recent times?
A 1960 Chilean earthquake, which occurred off the coast, had a magnitude of 9.6 and broke a fault more than 1,000 miles (1,600 kilometers) long. An earthquake like that under a major city would challenge the best construction techniques.
17. Which earthquake was more catastrophic: Kobe, Japan or Northridge, California?
The 1994 Northridge earthquake had a magnitude of 6.7 was responsible for approximately 60 deaths, 9,000 injuries, and more than $40 billion in damage. The Kobe earthquake of 1995 was magnitude 6.8 and killed 5,530 people. There were some 37,000 injuries and more than $100 billion in economic loss.
18. How far is it to the center of the Earth?
The distance from the surface of Earth to the center is about 3,963 miles (6,378 kilometers). Much of Earth is fluid. The mostly solid skin of the planet is only 41 miles (66 kilometers) thick -- thinner than the skin of an apple, relatively speaking.
19. What is the highest mountain?
Climbers who brave Mt. Everest in the Nepal-Tibet section of the Himalayas reach 29,035 feet (nearly 9 kilometers) above sea level. Its height was revised upward by 7 feet based on measurements made in 1999 using the satellite-based Global Positioning System.
20. Has the Moon always been so close?
It used to be much closer! A billion years ago, the Moon was in a tighter orbit, taking just 20 days to go around us and make a month. A day on Earth back then was only 18 hours long. The Moon is still moving away -- about 1.6 inches (4 centimeters) a year. Meanwhile, Earth's rotation is slowing down, lengthening our days. In the distant future, a day will be 960 hours long! [ Find out why]
21. Where is the lowest dry point on Earth?
The shore of the Dead Sea in the Middle East is about 1,300 feet (400 meters) below sea level. Not even a close second is Bad Water in Death Valley, California, at a mere 282 feet below sea level.
22. Good thing California isn't sinking further, right?
Actually parts of it are, which is so interesting that I snuck this non-question onto the list. In a problem repeated elsewhere in the country, the pumping of natural underground water reservoirs in California is causing the ground to sink up to 4 inches (11 centimeters) per year in places. Water and sewage systems may soon be threatened.
23. What is the longest river?
The Nile River in Africa is 4,160 miles (6,695 kilometers) long.
24. What is the most earthquake-prone state in the United States?
Alaska experiences a magnitude 7 earthquake almost every year, and a magnitude 8 or greater earthquake on average every 14 years. Florida and North Dakota get the fewest earthquakes in the states, even fewer than New York .
25. What's the driest place on Earth?
A place called Arica, in Chile, gets just 0.03 inches (0.76 millimeters) of rain per year. At that rate, it would take a century to fill a coffee cup.
26. What causes a landslide?
Intense rainfall over a short period of time can trigger shallow, fast-moving mud and debris flows. Slow, steady rainfall over a long period of time may trigger deeper, slow-moving landslides. Different materials behave differently, too. Every year as much as $2 billion in landslide damage occurs in the United States. In a record-breaking storm in the San Francisco area in January 1982, some 18,000 debris flows were triggered during a single night! Property damage was over $66 million, and 25 people died.
27. How fast can mud flow?
Debris flows are like mud avalanches that can move at speeds in excess of 100 mph (160 kph).
28. Do things inside Earth flow?
You bet. In fact, scientists found in 1999 that molten material in and around Earth's core moves in vortices, swirling pockets whose dynamics are similar to tornadoes and hurricanes. And as you'll learn later in this list, the planet's core moves in other strange ways, too.
29. What is the wettest place on Earth?
Lloro, Colombia averages 523.6 inches of rainfall a year, or more than 40 feet (13 meters). That's about 10 times more than fairly wet major cities in Europe or the United States.
30. Does Earth go through phases, like the Moon?
From Mars, Earth would be seen to go through distinct phases (just as we see Venus change phases). Earth is inside the orbit of Mars, and as the two planets travel around the Sun, sunlight would strike our home planet from different angles during the year. Earth phases can be seen in recent photographs taken by Mars Global Surveyor and the European Mars Express
31. What is the largest canyon?
The Grand Canyon is billed as the world's largest canyon system. Its main branch is 277 miles (446 kilometers) long. But let's compare. Valles Marineris on Mars extends for about 3,000 miles (4,800 kilometers). If added it to a U.S. map, it would stretch from New York City to Los Angeles. In places this vast scar on the Martian surface is 5 miles (8 kilometers) deep.
32. What is the deepest canyon in the United States?
Over the eons, the Snake River dug Hell's Canyon along the Oregon-Idaho border. It is more than 8,000 feet (2.4 kilometers) deep. In contrast, the Grand Canyon is less than 6,000 feet deep -- a bit more than a mile.
33. Is Earth the largest rocky planet in the solar system?
Just barely! Earth's diameter at the equator is 7,926 miles (12,756 kilometers). Venus is 7,521 miles (12,104 kilometers) wide. Mercury and Mars, the other two inner rocky planets, are much smaller. Pluto is rocky, too, but it's comparatively tiny (and some say it is not a planet at all).
34. How many of Earth's volcanoes are known to have erupted in historic time?
About 540 volcanoes on land are known. No one knows how many undersea volcanoes have erupted through history.
35. Is air mostly oxygen?
Earth's atmosphere is actually about 80 percent nitrogen. Most of the rest is oxygen, with tiny amounts of other stuff thrown in.
36. What is the highest waterfall in the United States?
Yosemite Falls in California is 2,425 feet (739 meters).
37. What percentage of the world's water is in the oceans?
About 97 percent. Oceans make up about two-thirds of Earth's surface, which means that when the next asteroid hits the planet, odds are good it will splash down.
38. Which two landmasses contain the vast majority of the Earth's fresh water supply?
Nearly 70 percent of the Earth's fresh-water supply is locked up in the icecaps of Antarctica and Greenland. The remaining fresh-water supply exists in the atmosphere, streams, lakes, or groundwater and accounts for a mere 1 percent of the Earth's total.
39. Which of the Earth's oceans is the largest?
The Pacific Ocean covers 64 million square miles (165 million square kilometers). It is more than two times the size of the Atlantic. It has an average depth of 2.4 miles (3.9 kilometers).
40. Why is Earth mostly crater-free compared to the pockmarked Moon?
Earth is more active, in terms of both geology and weather. Much of our planet's geologic history was long ago folded back inside. Some of that is regurgitated by volcanoes, but the results are pretty hard to study. Even more recent events evident on the surface -- craters that can by millions of years old -- get overgrown by vegetation, weathered by wind and rain, and modified by earthquakes and landslides. The Moon, meanwhile, is geologically quiet and has almost no weather; its craters tell a billions-year-long tale of catastrophic collisions. Interestingly, some of the oldest Earth rocks might be awaiting discovery on the Moon, having been blasted there billions of years ago by the very asteroid impacts that rattle both worlds.
41. How much surface area does Earth contain?
There are 196,950,711 square miles (510,100,000 square kilometers).
42. What is the largest lake in the world?
By size and volume it is the Caspian Sea, located between southeast Europe and west Asia.
43. Where do most earthquakes and volcanic eruptions occur on Earth?
The majority occur along boundaries of the dozen or so major plates that more or less float on the surface of Earth. One of the most active plate boundaries where earthquakes and eruptions are frequent, for example, is around the massive Pacific Plate commonly referred to as the Pacific Ring of Fire. It fuels shaking and baking from Japan to Alaska to South America.
44. How hot are the planet's innards?
The temperature of Earth increases about 36 degrees Fahrenheit (20 degrees Celsius) for every kilometer (about 0.62 miles) you go down. Near the center, its thought to be at least 7,000 degrees Fahrenheit (3,870 Celsius).
45. What three countries have the greatest number of historically active volcanoes?
The top three countries are Indonesia, Japan, and the United States in descending order of activity.
46. How many people worldwide are at risk from volcanoes?
As of the year 2000, USGS scientists estimated that volcanoes posed a tangible risk to at least 500 million people. This is comparable to the entire population of the world at the beginning of the seventeenth century!
47. Which of the following sources stores the greatest volume of fresh water worldwide: lakes, streams or ground water?
Groundwater comprises a 30 times greater volume than all freshwater lakes, and more than 3,000 times what's in the world's streams and rivers at any given time. Groundwater is housed in natural underground aquifers, in which the water typically runs around and through the stone and other material.
48. Which earthquake was larger, the 1906 San Francisco earthquake or the 1964 Anchorage, Alaska, temblor?
The Anchorage earthquake had a magnitude of 9.2, whereas the San Francisco earthquake was a magnitude 7.8. This difference in magnitude equates to 125 times more energy being released in the 1964 quake and accounts for why the Anchorage earthquake was felt over an area of almost 500,000 square miles (1,295,000 square kilometers).
49. Which earthquake was more destructive in terms of loss of life and relative damage costs, the 1906 San Francisco earthquake or the 1964 Anchorage earthquake?
The 1906 San Francisco earthquake tops this category. It was responsible for 700 deaths versus 114 from the Anchorage earthquake. Property damage in San Francisco was also greater in relative terms due to the destructive fires that destroyed mostly wooden structures of the time.
50. Is Earth's core solid?
The inner portion of the core is thought to be solid. But the outer portion of the core appears molten. We've never been there though, so scientists aren't sure of the exact composition. A radical Hollywood-like idea was recently put forth to blow a crack in the planet and send a probe down there to learn more. An interesting bit of recent evidence shows Mars' core may be similarly squishy. Scientists figured this out by studying tides on Mars ( tides on Mars? ).
51. Does all of Earth spin at the same rate?
The solid inner core -- a mass of iron comparable to the size of the Moon -- spins faster than the outer portion of the iron core, which is liquid. A study in 1996 showed that over the previous century, the extra speed caused the inner core to gain a quarter-turn on the planet as a whole. So the inner core makes a complete revolution with respect to the rest of Earth in about 400 years. Immense pressure keeps it solid.
52. How many people have been killed by volcanoes during the last 500 years?
At least 300,000. Between 1980 and 1990, volcanic activity killed at least 26,000 people.
53. How much of the Earth's surface consists of volcanic rock?
Scientists estimate that more than three-quarters of Earth's surface is of volcanic origin-- that is, rocks either erupted by volcanoes or molten rock that cooled below ground and has subsequently been exposed at the surface. Most of Earth's volcanic rocks are found on the sea floor.
54. Can an earthquake cause a tsunami?
If the earthquake originates under the ocean, yes. Near the earthquake's epicenter, the sea floor rises and falls, pushing all the water above it up and down. This motion produces a wave that travels outward in all directions. A tsunami can be massive but remain relatively low in height in deep water. Upon nearing the shore, it is forced up and can reach the height of tall buildings. One in 1964 was triggered in Alaska and swamped the small northern California town of Crescent City, moving train cars several blocks and killing several people there. Asteroids can cause tsunami , too.
55. Are all tsunamis high waves when they strike a coastline?
No, contrary to many artistic images of tsunamis, most do not result in giant breaking waves. Rather, most tsunamis come onshore more like very strong and fast tides. The water can rise higher than anyone along a given shore area has ever seen, however . [Model of an East Coast tsunami ]
56. How much of the Earth's land surface is desert?
About one-third.
57. What's the deepest place in the ocean?
The greatest known depth is 36,198 feet (6.9 miles or 11 kilometers) at the Mariana Trench, in the Pacific Ocean well south of Japan near the Mariana Islands.
58. What is the fastest surface wind ever recorded?
The fastest "regular" wind that's widely agreed upon was 231 mph (372 kph), recorded at Mount Washington, New Hampshire, on April 12, 1934. But during a May 1999 tornado in Oklahoma, researchers clocked the wind at 318 mph (513 kph). For comparison, Neptune's winds can rage to 900 mph (1,448 kph).
59. How much fresh water is stored in the Earth?
More than two million cubic miles of fresh water is stored in the planet, nearly half of it within a half-mile of the surface. Mars, too, appears to have a lot of water near its surface, but what's been detected so far is locked up as ice; nobody has estimated how much might be there.
60. How old is Earth?
Our planet is more than 4.5 billion years old, just a shade younger than the Sun. Recent evidence actually shows that Earth was formed much earlier than previously believed, just 10 million years after the birth of the Sun, a stellar event typically put at 4.6 billion years ago.
61. What is the world's largest desert?
The Sahara Desert in northern Africa is more than 23 times the size of southern California's Mojave Desert. [Several readers have e-mailed to suggest that arid Antarctica technically tops this category; true, some researchers put it there, but most lists of deserts don't include it.]
62. Which planet has more moons, Earth or Mars?
Mars has two satellites, Phobos and Deimos. The Earth has only one natural satellite, but it's the Moon. The outer planets have lots of Moon, most of them found fairly recently and leading to the possibility that scientists might one day need to redefine what it means to be a moon.
63. What is the world's deepest lake?
Lake Baikal in the south central part of Siberia is 5,712 feet (1.7 kilometers) deep. It's about 20 million years old and contains 20 percent of Earth's fresh liquid water.
64. What is the origin of the word "volcano"?
It derives from Vulcan, the Roman god of fire.
65. How many minerals are known to exist?
There are roughly 4,000 known minerals, although only about 200 are of major importance. Approximately 50-100 new minerals are described each year.
66. What is the total water supply of the world?
The total water supply of the world is 326 million cubic miles (1 cubic mile of water equals more than 1 trillion gallons).
67. What is the world's largest island?
Greenland covers 840,000 square miles (2,176,000 square kilometers). Continents are typically defined as landmasses made of low-density rock that essentially floats on the molten material below. Greenland fits this description, but it's only about one-third the size of Australia. Some scientists call Greenland an island, others say it's a continent.
68. Where are most of Earth's volcanoes?
The most prominent topographic feature on Earth is the immense volcanic mountain chain that encircles the planet beneath the sea -- the chain is more than 30,000 miles (48,000 kilometers) long and rises an average of 18,000 feet ( 5.5 kilometers) above the seafloor. It is called the mid-ocean ridge and is where Earth's plates spread apart as new crust bubbles up -- volcanic activity. There are more volcanoes here than on land. The spreading, however, leads to scrunching when these plates slam into the continents. The result: More volcanoes and earthquakes in places like California and Japan.
69. What volcano killed the most people?
The eruption of Tambora volcano in Indonesia in 1815 is estimated to have killed 90,000 people. Most died from starvation after the eruption, though, because of widespread crop destruction, and from water contamination and disease.
70. Were Earth and the Moon separated at birth?
Not quite. But leading theory holds that our favorite satellite was carved partly from Earth shortly after the Earth formed. A Mars-sized object slammed into our fledgling planet. The impactor was destroyed. Stuff flew everywhere and a lot of it went into orbit around Earth. The Moon gathered itself together out of the largely vaporized remains of the collision, while Earth hung in there pretty much intact.
71. How many lightning strikes occur worldwide every second?
On average, about 100. Those are just the ones that hit the ground, though. During any given minute, there are more than a thousand thunderstorms around the Earth causing some 6,000 flashes of lightning. A lot of it goes from cloud-to-cloud.
72. Are rivers alive?
Not in the traditional sense, of course. But like all living creatures, rivers have a life span. They are born, grow in size, and they age. They can even die during the span of geological time.
73. Can asteroids create islands?
Speculation has existed for decades that ancient asteroid impacts might create hot spots of volcanic activity, which could give rise to mountains that poke up through seas that didn't used to be there. There's no firm answer to this question, but a recent computer model suggested Hawaii might have been formed in this manner .
74. Is the state of Louisiana growing or shrinking?
Louisiana loses about 30 square miles (78 square kilometers) of land each year to coastal erosion, hurricanes, other natural and human causes and a thing called subsidence, which means sinking. Much of New Orleans actually sits 11 feet ( 3.4 meters) below sea level. Parts of the French quarter have sunk 2 feet in the past six decades. The city is protected by dikes, but all experts agree that storm tides from a direct hit by a major hurricane would breach the system and swamp much of the city. In 2000, the director of the U.S. Geological Survey, Chip Groat, said: "With the projected rate of subsidence, wetland loss and sea-level rise, New Orleans will likely be on the verge of extinction by this time next century."
75. How much would seas rise if the Antarctic Ice Sheet melted?
The Antarctic Ice Sheet holds nearly 90 percent of the world's ice and 70 percent of its fresh water. If the entire ice sheet were to melt, sea level would rise by nearly 220 feet, or the height of a 20-story building. Scientists know there's a melting trend underway. The United Nations has said that in a worst-case scenario -- depending on how much global air temperatures increase -- seas could jump 3 feet (1 meter) by 2100.
76. Is ice a mineral?
Yes, ice is a mineral and is formally described as such in Dana's System of Mineralogy.
77. What is the softest of all minerals?
Talc is the softest of minerals. It is commonly used to make talcum powder.
78. What is the hardest of all minerals?
The one that becomes emotionally useless after a divorce but still retains monetary value.
79. How are colors produced in fireworks?
Mineral elements taken from Earth provide the colors. Strontium yields deep reds, copper produces blue, sodium yields yellow, and iron filings and charcoal pieces produce gold sparks. Bright flashes and loud bangs come from aluminum powder.
80. Does Earth have the worst weather in the solar system?
Right now, it's the worst that most humans I know ever experience. But there's lots of wilder weather elsewhere. Mars can whip up hurricane-like storms four times bigger than Texas. Dust storms on the red planet can obscure the entire globe! Jupiter has a hurricane twice the size our entire planet, and it's lasted for at least three centuries ( another storm on Jupiter is even bigger). Venus is a living hell, and Pluto is routinely more frigid than the coldest place on Earth (though may change one day, and Pluto may in fact become the last oasis for life).
81. Where are the highest tides?
In Burntcoat Head, Minas Basin, part of the Bay of Fundy in Nova Scotia, tides can range 38.4 feet (11.7 meters). The bay is funnel shaped -- its bottom slopes upward continuously from the ocean inlet. The result is an extreme "tidal bore," a wave-like phenomenon at the leading edge of the changing tide. Bores in Fundy can travel up feeder rivers at 8 mph (13 kph) and be more than 3 feet (1 meter) tall.
82. Where is the world's only equatorial glacier?
Mt. Cotopaxi in Ecuador supports the only glacier on the equator.
83. What is the largest lake in North America?
Lake Superior.
84. What's the deadliest hurricane to ever hit the United States?
A Category 4 hurricane hit Galveston, Texas in 1900 and killed more than 6,000 people (read about the history of it here). The next closest death toll was less than 1,900 from a 1928 Florida hurricane.
85. What is the longest mountain chain on Earth?
The Mid-Atlantic Ridge, which splits nearly the entire Atlantic Ocean north to south. Iceland is one place where this submarine mountain chain rises above the sea surface.
86. How much gold has been discovered worldwide to date?
More than 193,000 metric tons (425 million pounds). If you stuck it all together, it would make a cube-shaped, seven-story structure that might resemble one of Donald Trump's buildings. First you'd have to find all those rings that have gone down the drain.
87. What are the two major gold-producing countries?
South Africa produces 5,300 metric tons per year, and the United States produces more than 3,200 metric tons.
88. What North American plant can live for thousands of years?
The creosote bush, which grows in the Mojave, Sonoran, and Chihuahuan deserts, has been shown by radiocarbon dating to have lived since the birth of Christ. Some of these plants may endure 10,000 years, scientists say. If only they could talk.
89. On average, how much water is used worldwide each day?
About 400 billion gallons.
90. Is Saturn the only ringed planet?
Saturn has the most obvious rings. But Jupiter and Neptune both have subtle ring systems, [as does Uranus, readers reminded me]. And even Earth may once have been a ringed planet, the result of some space rock's glancing blow.
91. Where are the highest tides?
In Burntcoat Head, Minas Basin, part of the Bay of Fundy in Nova Scotia, tides can range 38.4 feet (11.7 meters). The bay is funnel shaped -- its bottom slopes upward continuously from the ocean inlet. The result is an extreme "tidal bore," a wave-like phenomenon at the leading edge of the changing tide. Bores in Fundy can travel up feeder rivers at 8 mph (13 kph) and be more than 3 feet (1 meter) tall.
92. Where is the world's only equatorial glacier?
Mt. Cotopaxi in Ecuador supports the only glacier on the equator.
93. What is the largest lake in North America?
Lake Superior.
94. What's the deadliest hurricane to ever hit the United States?
A Category 4 hurricane hit Galveston, Texas in 1900 and killed more than 6,000 people (read about the history of it here). The next closest death toll was less than 1,900 from a 1928 Florida hurricane.
95. What is the longest mountain chain on Earth?
The Mid-Atlantic Ridge, which splits nearly the entire Atlantic Ocean north to south. Iceland is one place where this submarine mountain chain rises above the sea surface.
96. How much gold has been discovered worldwide to date?
More than 193,000 metric tons (425 million pounds). If you stuck it all together, it would make a cube-shaped, seven-story structure that might resemble one of Donald Trump's buildings. First you'd have to find all those rings that have gone down the drain.
97. What are the two major gold-producing countries?
South Africa produces 5,300 metric tons per year, and the United States produces more than 3,200 metric tons.
98. What North American plant can live for thousands of years?
The creosote bush, which grows in the Mojave, Sonoran, and Chihuahuan deserts, has been shown by radiocarbon dating to have lived since the birth of Christ. Some of these plants may endure 10,000 years, scientists say. If only they could talk.
99. On average, how much water is used worldwide each day?
About 400 billion gallons.
100. Is Saturn the only ringed planet?
Saturn has the most obvious rings. But Jupiter and Neptune both have subtle ring systems, [as does Uranus, readers reminded me]. And even Earth may once have been a ringed planet, the result of some space rock's glancing blow.
1 The Purest Form Of Iron Is Wrought Iron
2 Leaves Change Colour In Autumn Due To Shortage Of
Chlorophyll
3 Tuberculosis Is A Disease Of Lungs Caused By Bacteria
4 The Green Leaves Of The Trees Turn Brown And Fall In Autumn
Because The Pedical Of Leaves Is Weaken Beacause Of Deficiency
Of Starch
5 The Fungi Causes Maximium Spoilage To Out Cereal Crops
6 A True Fruit Is Drived From The Ovary Of Flower
7 Blood Cells Are Manufactured By Bone Morrow Of The Body
8 W.shockly Invented Transistor
9 Microphone Is Invention Of Berliner
10 Dr Charles Invented Laser
11 Udometer:it Is A Rain Gauge,used To Measure Rain Water
12 When A Bullet Penetrates Into A Target,the Kinetic Energy Of
The Bullet Is Converted Into Mechanical Energy
13 Watson And Crick Discovered D.n.a
14 Bicycle Is Invention Of Macmillon
15 Conversion Of Milk Into Curd Is Done By Lactic Acid And Bacteria
16 Sometimes When White Blood Corpuscles Greatly Increase In
Number They Cause A Disease Called Leukemia
17 The Age Of Tree Is Determined By By Counting Its Rings
18 The Velocity Of Light Is More Than The Velocity Of Sound That
Is Why We Hear Thunder After,and See Flash Of Light First
19 The Scientific Study Of Old Age Is Called Gerontology
20 Chlorofloro Carbons Cause Decomposition Of Ozone Laye
UNIVERSE
PLANET - ATTRIBUTE - MOON - ATMOSPHERE - REVOLUTIONARY PERIOD
Mercury (58 ml km) - Smallest - No - No - 88 -
Venus - Hottest - No - CO2 - 225
Earth – dia 12756 km, rad 6400 km - Colorful - 1 - N2,O2, argon, CO2,Neon, Helium, Methane, H2 - 365.25
Mars - Red - 2 - Dark cloudy, H2 & Helium - 687
Jupitar - Biggest/Heaviest, - shortest day - 61 - H2 and Helium - 11.86yr
Saturn - Brightest - 23 - Rings of ice & dust - 29.46yr
Uranus - Green due to Methane layer, - hottest, longest day - 15 - H2 and Helium - 84.01yrs
Neptune (5900 m km far) - Blue due to Methane layer - 2 - H2 and Helium - 164.8yrs
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