Showing posts with label General Science. Show all posts
Showing posts with label General Science. Show all posts

Tuesday, April 12, 2011

Everyday Science Simplified

Everyday Science Simplified

  • Q.   A man with a load jumps from a high building. What will be the load experienced by him?
    A.   Zero, because the acceleration of his fall is equal to the acceleration due to gravity of the earth.

  • Q.   A piece of chalk when immersed in water, emits bubbles. Why ?
    A.   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.

  • Q.   Why does a liquid remain hot or cold for a long time inside a thermos flask?
    A.  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.

  • Q.   Why does a ball bounce upon falling?
    A.   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).

  • Q.   Why is standing in boats or double decker buses not allowed, particularly in the upper deck of buses?
    A.   On tilting the centre of gravity of the boat or bus is lowered and it is likely to overturn.

  • Q.   Why is it recommended to add salt to water while boiling dal?
    A.   By addition of salt the boiling point of water gets raised which helps in cooking.

  •  Q.   Why is the boiling point of sea water more than that of pure water?
    A.    Sea water contains salt, and other impurities with different boiling points, which jointly raise its boiling point.

  • Q.   Why is it easier to spray water to which soap is added?
    A.   Addition of soap decreases the surface tension of water. The energy for spraying is directly proportional to surface tension.

  • Q.   Which is more elastic, rubber or steel?
    A.   Steel is more elastic for the same stress produced compared with rubber.

  • Q.   Why is the sky blue?
    A.   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.

  • Q.   Why does ink leak out of partially filled pen when taken to a higher altitude?
    A.   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.

  • Q.   On the moon, will the weight of a man be less or more than his weight on the earth?
    A.   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.

  • Q.   Why do some liquids burn while others do not?
    A.    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.

  • Q.   Why can we see ourselves in a mirror? 
    A.    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.

  • Q.   Why does a solid chunk of iron sink in water but float in mercury? 
    A.    Because the density of iron is more than that of water but less than that of mercury.

  • Q.   Why is cooking quicker in a pressure cooker?
    A.    As the pressure inside the cooker increases, the boiling point of water is raised, hence, the cooking process is quicker.

  • Q.   When wood burns it crackles. Explain? 
    A.    Wood contains a complex mixture of gases and tar forming vapours trapped under its surface. These gases and tar vapours escape, making a crackling sound.

  • Q.   Why do stars twinkle? 
    A.    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 appears as if the stars are twinkling.

  • Q.   Why is it easier to roll a barrel than to pull it?
    A.    Because the rolling force of friction is less than the dynamic force of sliding friction.

  • Q.   If a feather, a wooden ball and a steel ball fall simultaneously in a vacuum, which one of these would fall faster?
    A.    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.

  • Q.   When a man fires a gun, he is pushed back slightly. Why?
    A.    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 an equal momentum in a backward direction.

  • Q.   Ice wrapped in a blanket or saw dust does not melt quickly. Why? 
    A.    Both wood and wool are bad conductors of heat. They do not permit heat rays to reach the ice easily.

  • Q.   Why do we perspire on a hot day?
    A.    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.

  • Q.   Why does ice float on water but sink in alcohol?
    A.    Because ice is lighter than water it floats on it. However, ice is heavier than alcohol and therefore it sinks in alcohol.

  • Q.   Why do we perspire before rains?A.    Before the rain falls, the atmosphere gets saturated with water vapour, as a result, the process of evaporation of sweat is delayed.

  • Q.   Why does a thermometer kept in boiling water show no change in reading after 100°C?A.    The boiling point of water is 100°C. Once water starts boiling at this temperature, thermometer records no change in temperature. The quantity of heat supplied is being utilised as latent heat of evaporation to convert the water at boiling point into vapour.

  • Q.   Why do we bring our hands close to the mouth while shouting across to someone far away?
    A.    By keeping hands close to mouth the sound is not allowed to spread (phenomenon of diffraction of sound) in all directions but is directed to a particular direction and becomes louder.

  • Q.   Why does a corked bottle filled with water burst if left out on a frosty night?
    A.    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.

  • Q.   Why is a small gap left at the joint between two rails?
    A.    To permit expansion of rails due to heat generated by friction of a moving train. 

  • Q.   Why cannot a copper wire be used to make elements in electric heater?
    A.    Copper melts at I08.3°C and forms a black powder on reacting with atmospheric oxygen. For heater elements a metal should have more resistance to produce heat.

  • Q.   Why are water or mercury droplets always round .when dropped on a clean glass?
    A.  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 the sphere has minimum volume.

  • Q.   Why does a balloon filled with hydrogen rise in the air?
    A.    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.

  • Q.   Why do we lean forward while climbing a hill?
    A.    In order to keep the vertical line passing through our centre of gravity always between our feet, which is essential to attain equilibrium or stability.

  • Q.   Why does smoke curl up in the air?
    A.    Smoke contains hot gases which being lighter in weight, follow a curved path because of the eddy currents that are set up in the air.

  • Q.   Why does an electric bulb explode when it is broken?
    A.    The bulb encompasses partial vacuum and as it breaks, air rushes in causing a small explosion.

  • Q.   Why does a man fall forward when he jumps out of a running train or bus?
    A.    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.

  • Q.   Why does an ordinary glass tumbler crack when very hot tea or milk is poured in it?A.    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.

  • Q.   Why is a compass used as an indicator of direction?A.    The magnetic needles of a compass under the influence of the earth's magnetic field lie in a north-south direction. Hence, we can identify direction.

  • Q.   Why is water from a hand pump warm in winter and cold in summer? A.    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.

  • Q.   Why is a rainbow seen after a shower?A.    After a shower the clouds containing water droplets act like a prism through which the white light is dispersed producing a spectrum.

  • Q.   Why does a swimming pool appear less deep than it actually is?A.    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.

  • Q.   Why is one's breath visible in winter but not in summer?A.    In winter, water vapour contained in the breath condenses into small droplets which become visible but in summer they are quickly evaporated and not seen.

  • Q.   Why doesn't the electric filament in an electric bulb burn up?A.    Firstly, because it is made of tungsten which has a very high melting point (341O°C) whereas the temperature of the filament required to glow is only 2700°C. Secondly, oxygen is absent since the bulb is filled with an inert gas which does not help in burning.

  • Q.   Why does blotting paper absorb ink?A.    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 of liquids) and is absorbed.

  • Q.   Why does a small ball of iron sink in water but a large ship float?A.   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).

  • Q.   Why does ice float on water?A.   The weight of the ice block is equal to the weight of the liquid displaced by the immersed portion of the ice.

  • Q.   Why does moisture gather outside a tumbler containing cold water? A.   The water vapour in the air condenses on cooling and appears as droplets of water.

  • Q.   Why does kerosene float on water?A.   Because the density of kerosene is less than that of water. For the same reason cream rises in milk and floats at the top.

  • Q.   Why is the water in an open pond cool even on a hot summer day?A.   As the water evaporates from the open surface of a pond, heat is taken away in the process, leaving the surface cool.

  • Q.   Why is it less difficult to cook rice or potatoes at higher altitudes?A.   Atmospheric pressure at higher altitudes is low and boils water below 100°C. The boiling point of water is directly proportional to the pressure on its surface.

  • Q.   Why is it difficult to breathe at higher altitudes?A.   Because of low air pressure at higher altitudes the quantity of air is less, and so also that of oxygen.

  • Q.   Why are winter nights and summer nights warmer during cloudy weather than when the sky is clear?
    A.   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.

  • Q.   Why is a metal tyre heated before it is fixed on wooden wheels? A.   On heating, the metal tyre expands by which its circumference also increases. This makes fixing the wheel easier and thereafter cooling down shrinks it; thus fixing the tyre tightly.

  • Q.   Why is it easier to swim in the sea than in a river? A.   The density of sea water is higher; hence the upthrust is more than that of river water.

  • Q.   Who will possibly learn swimming faster–a fat person or a thin person? A.   The fat person displaces more water which will help him float much more freely compared to a thin person.

  • Q.   Why is a flash of lightening seen before thunder? A.   Because light travels faster than sound, it reaches the earth before the sound of thunder.

  • Q.   Why cannot a petrol fire be extinguished by water? A.   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.

  • Q.   Why does water remain cold in an earthen pot?A.   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.

  • Q.   Why do we place a wet cloth on the forehead of a patient suffering from high temperature?A.   Because of body's temperature, water evaporating from the wet cloth produces a cooling effect and brings the temperature down.

  • Q.   When a needle is placed on a small piece of blotting paper which is placed 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?
    A.   The surface tension of clean water being higher than that of a soap solution, it can 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.

  • Q.   To prevent multiplication of mosquitoes, it is recommended to sprinkle oil in the ponds with stagnant water. Why?
    A.   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.

  • Q.   Why does oil rise on a cloth tape of an oil lamp?A.   The pores in the cloth tape suck oil due to the capillary action of oil.

  • Q.   Why are ventilators in a room always made near the roof?A.   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.

  • Q.   How does ink get filled in a fountain pen?A.   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.

  • Q.   Why are air coolers less effective during the rainy season?A.   During the rainy reason the atmospheric 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.

  • Q.   Why does grass gather more dew in nights than metallic objects such as stones?A.   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 radiators and bad conductors.

  • Q.   If a lighted paper is introduced in a jar of carbon dioxide, its flame extinguishes. Why?A.   Because carbon dioxide does not help in burning. For burning, oxygen is required.

  • Q.   Why does the mass of an iron rod increase on rusting?A.   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.

  • Q.   Why does milk curdle?A.   Lactose (milk sugar) content of milk undergoes fermentation and changes into lactic acid which on reacting forms curd.

  • Q.   Why does not hard water lather soap profusely?A.   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.

  • Q.   Why is it dangerous to have charcoal fire burning in a closed room? A.   When charcoal bums it produces carbon monoxide which is suffocating and can cause death.

  • Q.   Why is it dangerous to sleep under trees at night?A.   Plants respire at night and give out carbon dioxide which reduces the oxygen content of air required for breathing.

  • Q.   Why does ENO's salt effervesce on addition of water?A.   It contains tartaric acid and sodium bicarbonate. On adding water, carbon dioxide is produced which when released into water causes effervescence.

  • Q.   Why does milk turn sour?A.   The microbes react with milk and grow. They turn lactose into lactic acid which is sour in taste.

  • Q.   Why is a new quilt warmer than an old one?A.   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.

  • Q.   Eskimos live in double-walled ice houses. Why?A.   Because the air in between two ice walls does not allow heat to pass.

  • Q.   Curved rail tracks or curved roads are banked or raised on one side. Why?A.   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.

  • Q.   How do bats fly in dark? A.   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.

  • Q.   Water pipes often burst at hill stations on cold frosty nights. Why? A.   The temperature may fall below 0³C 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.

  • Q.   Why are 'white clothes more comfortable in summer than dark or black ones?A.   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.

  • Q.   Why is rose red and grass green in daylight?A.   Rose absorbs all the constituent colours of white light except red which is reflected to us. Similarly, grass absorbs all colours except green which is reflected to us.

  • Q.   Why does a ship rise as it enters the sea from a river?A.   The density of sea water is high due to impurities and salts compared to river water. As a result, the upthrust produced by the sea water on the ship is more than that of river water.

  • Q.   Why are fuses provided in electric installations?A.   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.

  • Q.   Why is it easier to lift a heavy object under water than in air?A.   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 portion, and hence, is easier to lift objects.

  • Q.   If a highly pumped up bicycle tyre is left in the hot sunlight, it bursts. Why?A.   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.

  • Q.   What will be the colour of green grass in blue light?A.   Grass will appear dark in colour because it absorbs all other colours of the light except its own green colour. The blue light falling on grass will be absorbed by it, and hence, it will appear dark in colour.

  • Q.   Why do two eyes give better vision than one?A.   Because two eyes do not form exactly similar images and the fusion of these two dissimilar images in the brain gives three dimensions of the stereoscopic vision.

  • Interesting Environmental Facts

    Interesting Environmental Facts

    Human Influenced Facts
    • If just 25% of U.S. families used 10 fewer plastic bags a month, we would save over 2.5 BILLION bags a year.
    • On the average, the 140 million cars in America are estimated to travel almost 4 billion miles in a day, and according to the Department of Transportation, they use over 200 million gallons of gasoline doing it.
    • Every year we throw away 24 million tons of leaves and grass. Leaves alone account for 75% of our solid waste in the fall.
    • Over 100 pesticide ingredients are suspected to cause birth defects, cancer, and gene mutations.
    • Every ton of recycled office paper saves 380 gallons of oil.
    • About 1% of U.S. landfill space is full of disposable diapers, which take 500 years to decompose.
    • Energy saved from one recycled aluminum can will operate a TV set for 3 hours, and is the equivalent to half a can of gasoline.
    • Glass produced from recycled glass instead of raw materials reduces related air pollution by 20%, and water pollution by 50%.
    • Americans use 50 million tons of paper annually -- consuming more than 850 million trees.
    • Homeowners use up to 10 times more toxic chemicals per acre than farmers.
    • By turning down your central heating thermostat one degree, fuel consumption is cut by as much as 10%.
    • Insulating your attic reduces the amount of energy loss in most houses by up to 20%.
    • Enough glass was thrown away in 1990 to fill the Twin Towers (1,350 feet high) of New York's World Trade Center every two weeks.
    • One ton of carbon dioxide that is released in the air can be prevented by replacing every 75 watt light bulbs with energy efficient bulbs.
    • Many banks lent large sums of money to developing nations. In order to pay those debts plus interest many nations have turned to the mining of their natural resources as a source of financial aid.
    • Every day 40,000 children die from preventable diseases.
    • The public transportation that we have is a wreck. The U.S. continues to promote and invest in private car travel rather than public transportation.
    • The human population of the world is expected to be nearly tripled by the year 2100.
    • A three percent annual growth rate will result in the doubling of consumption and production of food and other products in 25 short years.  The amount of motor vehicles that are expected to be operated will increase 15 million a year until at least 2010.
    • The world's per capita grain production has been on the downfall since 1985 despite the use of fertilizers and pesticides.
    • Already a train system has been developed (back in 1987) which is based on magnetic levitation and causes minimal pollution. These versions of a train are already in use in several countries.
    • Fibre optics, made of glass, are being used to replace copper cables throughout the world.
    • The uncontrolled fishing that is allowed has reduced the amount of commercial species. Some species, up to one-tenth of their original population.
    • Every day 50 to 100 species of plants and animals become extinct as their habitat and human influences destroy them.

    The Earth
    • Deserts are advancing and taking over the land. In Mali the desert has taken over about 220 miles in as few as 20 years. Deserts can be repelled, by developing tree-planting projects, having better agriculture and by managing the land better. However, governments still are reluctant to fund anti-desertification, despite horrific droughts that have occurred in recent years.
    • The Earth has been around for 4.6 billion years. Scaling this time down to 46 years we have been around for 4 hours and our Industrial Revolution began just 1 minute ago. During this short time period we have ransacked the planet for ways to get fuels and raw materials, have been the cause of extinction of an unthinkable amount of plants and animals, and have multiplied our population to that of a plague.
    • Despite all of the damage we have caused the environment most of it is reversible. We can restore habitats and return species to them; clean rivers; renovate buildings; replenish the topsoil, replant forests. However, these activities do not relieve the worst symptoms of the damage. We still have to fix the source of these problems, us and our vision that we must progress.
    • In Peninsular Malaysia, more tree species are found in 125 acres of Tropical Forest than in the entire North America.
    • In Peru a single bush may contain more ant species than in the British Isles.
    • A study has shown that there are possibly over 30 million species of insects dwelling in the canopies of tropical forests.
    • 63,000 square miles of Rainforests are being destroyed each year.
    • Rainforests higher than 3,000 feet above sea level are called cloud forests.
    • Already over half of the world's tropical forests have been lost.
    • Madagascar is the home to a rainforest where 60 percent of it's 12,000 different plant species are unique to that island.
    • When you visit a pharmacist, one in every four purchases will have come from a tropical forest.
    • Medicine produced in tropical forests bring in commercially 30 billion dollars a year.
    • Large areas of South and Central America are cleared and burned for cattle ranching. This is so that farmers can provide cheap beef to consumers in the West.
    • Every year approximately four billion tons of carbon accumulates in the air each year, about 30% of this comes directly from the continued burning of the rainforests.
    • More than anything else, rainforest is destroyed by peasant farmers. However, the responsibility for this lies largely with the governments who fail to promote land reform and sustainable agricultural practices as an alternative to forest clearance.
    • Greater than a quarter of our rainforest is in Brazil.
    Interesting Animal Facts
    • Penguins live only in the Southern Hemisphere and never in the Northern Hemisphere.
    • A single porcupine is known to kill 100 trees in one winter. It uses it's sharp claws to climb a tree, sits on a limb to gnaw away at the bark and twigs and then stuffs them all into its mouth at once. Because of it's liking for bark, the porcupine causes much damage to forests.
    • A scallop moves by sucking water into its shell and then squirting it out suddenly. It likes to wander around and this gives it enough force to push it in front in a zig zag manner.
    • A male garibaldi damselfish attract females for mating by covering a rock with a thick layer of alga. A male which clean off a rock to allow only algae to live have a higher chance of mating. The algae is also used to protect the eggs of the fish.
    • To prevent the nest from getting soaked, the rare white-chinned swift, which nests behind the waterfalls of Latin America plant pieces of moss in the nest which then grow and reinforce the nest.
    • A porcupine loves salt so much that it would walk into a camp and gnaw on anything that has been touched by salt or even by perspiring hands.
    • Despite having a shell of armour for the body, an armadillo has teeth that do not have enamel and thus have very soft teeth. It can only eat soft food such as ants, termites, grubs and bugs.
    • The tip of an elephant's trunk is so sensitive and flexible that it can pick up a pin.
    • If a mole does not find food within 12 hours, it will die. Its chief food consists of insects and earthworms.
    • A male nightingale stops singing when its eggs have hatched so as not to attract unnecessary attention to the nest. However he gives short calls to tell the female that all is well or danger is approaching.
    • Bolas spiders snare moths by producing chemicals similar to pheromones used by several species of female moths to attract mates.
    • The webbed feet of the stormy petrel enable it to 'walk' on water. It spends almost its entire life over the ocean and only comes to land to breed. If a storm arises, they can't walk on water and are forced to remain in the air all day and night.
    • Some giant land turtles are able to bellow.
    • No one knows what happens to the seahorse during winter as it is only seen during the summertime.
    • There is a species in the river Nile in Egypt that avoids its enemies by swimming with its black belly up and its white back down.
    • The arctic tern, a migrating bird is able to travel back and forth as much as 22000 miles in a course of a year.
    • The Amazon army ants raid nests of certain black ants and carry back to cocoons and larvae to their own homes. When the cocoons hatch, they will become the slaves of these army ants and do all their work.
    • The nest that an osprey is a huge and attractive one which is unhidden from sight and the bird adds new material each year to the same old nest. The nest can weigh up to 450 kilograms.
    The Open Range
    • The Grasslands cover one-fifth of the land on Earth.
    • The majority of grasslands are found around the tropics.
    • Natural grasslands are; the savannahs of Africa, the North American prairies, and in southern USSR-the dry steppes.
    • Semi-natural grasslands are where the forest has been cleared and grazing, cutting or burning maintains the grass cover. Tending to be more productive most South and South-East Asian grasslands are semi-natural grasslands.
    • The temperate grassland soil contains a lot of organic material (more than the tropical)

    Top Ten Most Polluted Places in the World, 2007

    Top Ten Most Polluted Places in the World, 2007

    This Top Ten list was compiled by the Technical Advisory Board of the Blacksmith Institute, an environmental NGO based in New York. The criteria used in ranking the include the size of the affected population, the severity of the toxins involved, and reliable evidence of health problems associated with the pollution.
    • Sumgayit, Azerbaijan
      Forty factories that manufacture industrial and agricultural chemicals release 70-120,000 tons of detergents and pesticides into the air every year. Untreated sewage and mercury-contaminated sludge are dumped arbitrarily.
    • Linfen, China 
      Severe air and water pollution from the coal, steel, and tar industries.
    • Tianying, China 
      One of the largest lead production bases in China with average lead concentrations in the air and soils 8.5 to 10 times national health standards.
    • Sukinda, India 
      Twelve chromite ore mines dump untreated water into the river, and over 30 million tons of waste rock have been dumped in the valley's riverbanks, which has resulted in severe water contamination.
    • Vapi, India 
      There are over 1,00 industries covering over a thousand acres in the region that has contaminated local produce.
    • La Oroya, Peru 
      Lead, copper, zinc, and sulfur dioxide from mining have contaminative the town.
    • Dzerzhinsk, Russia 
      A major Russian chemical manufacturing center, which produced Sarin and other deadly poisons during the cold war. Between 1930-1998, nearly 300,000 tons of chemical waste were improperly disposed of.
    • Norilsk, Russia 
      An industrial city in Siberia founded in 1935 as a slave labor camp, Norilsk is home of the world's largest heavy metals smelting complex and is plagued by severe air pollution.
    • Chernobyl, Ukraine 
      The world's worst nuclear disaster took place on April 26, 1986. The 19-mile exclusion zone around the plant remains uninhabitable.
    • Kabwe, Zambia 
      The country's second largest city is severely contaminated with lead from the mining industry.

    Human Body Facts

    Human Body Facts

    Body Facts
    • In one day, a human sheds 10 billion skin flakes. This amounts to approximately two kilograms in a year.
    • Every square inch of the human body has about 19,000,000 skin cells.
    • Approximately 25% of all scald burns to children are from hot tap water and is associated with more deaths than with any other liquid.
    • Forty-one percent of women apply body and hand moisturizer at least three times a day.
    • Every hour one billion cells in the body must be replaced.
    • The world record for the number of body piercing on one individual is 702, which is held by Canadian Brent Moffat.
    • The small intestine in the human body is about 2 inches around, and 22 feet long.
    • The human body makes anywhere from 1 to 3 pints of saliva every 24 hours.
    • The human body has approximately 37,000 miles of capillaries.
    • The aorta, which is largest artery located in the body, is about the diameter of a garden hose.
    • The adult human body requires about 88 pounds of oxygen daily.
    • It is very common for babies in New Zealand to sleep on sheepskins. This is to help them gain weight faster, and retain their body heat.
    • An average women has 17 square feet of skin. When a women is in her ninth month of pregnancy she has 18.5 square feet of skin.
    • The width of your armspan stretched out is the length of your whole body.
    • 41% of women apply body or hand moisturizer a minimum three times a day.
    • A human's small intestine is 6 meters long.
    • There are as many hairs per square inch on your body as a chimpanzee. You don't see all of them because most are too fine and light to be noticed.
    • Every hour one billion cells in the body must be replaced.
    • Dead cells in the body ultimately go to the kidneys for excretion.
    • By walking an extra 20 minutes every day, an average person will burn off seven pounds of body fat in an year.
    • The human body is 75% water.
    Heart Facts
    • Women hearts beat faster than men.
    • Three years after a person quits smoking, there chance of having a heart attack is the same as someone who has never smoked before.
    • The human heart weighs less than a pound.
    • The human heart can create enough pressure that it could squirt blood at a distance of thirty feet.
    • The first open heart surgery was performed by Dr. Daniel Hall Williams in 1893.
    • Scientists have discovered that the longer the ring finger is in boys the less chance they have of having a heart attack.
    • The right lung of a human is larger than the left one. This is because of the space and placement of the heart.
    • The human heart beast roughly 35 million times a year.
    • Olive oil can help in lowering cholesterol levels and decreasing the risk of heart complications.
    • In a lifetime, the heart pumps about one million barrels of blood.
    • In 1967, the first successful heart transplant was performed in Cape Town, South Africa.
    • People that suffer from gum disease are twice as likely to have a stroke or heart attack.
    • Most heart attacks occur between the hours of 8 and 9 AM.
    • The human heart beast roughly 35 million times a year.
    • At one time it was thought that the heart controlled a person's emotions.
    Brain Facts
    • Women are twice as likely to be diagnosed with depression than men in the United States.
    • The human brain has about 100,000,000,000 (100 billion) neurons.
    • From all the oxygen that a human breathes, twenty percent goes to the brain.
    • People who ride on roller coasters have a higher chance of having a blood clot in the brain.
    • Once a human reaches the age of 35, he/she will start losing approximately 7,000 brain cells a day. The cells will never be replaced.
    • It is not possible to tickle yourself. The cerebellum, a part of the brain, warns the rest of the brain that you are about to tickle yourself. Since your brain knows this, it ignores the resulting sensation.
    • A women from Berlin Germany has had 3,110 gallstones taken out of her gall bladder.
    • In America, the most common mental illness is Anxiety Disorders.
    • Your brain is 80% water.
    • Your brain is move active and thinks more at night than during the day.
    Bones Facts
    • The smallest bone in the human body is the stapes bone which is located in the ear.
    • There are 54 bones in your hands including the wrists.
    • The only bone fully grown at birth is located in the ear.
    • The human face is made up of 14 bones.
    • The chances of getting a cavity is higher if candy is eaten slowly throughout the day compared to eating it all at once and then brushing your teeth.
    • If an identical twin grows up without having a certain tooth, the other twin will most likely also grow up with that tooth missing.
    • Humans are born with 300 bones in their body, however when a person reaches adulthood they only have 206 bones. This occurs because many of them join together to make a single bone.
    • Gardening is said to be one of the best exercises for maintaining healthy bones.
    • Enamel is hardest substance in the human body.
    • Although the outsides of a bone are hard, they are generally light and soft inside. They are about 75% water.
    • Adult human bones account for 14% of the body's total weight.
    • In 2000 babies are born with a tooth that is already visible.
    • Fingernails grow nearly 4 times faster than toenails!
    • Your thigh bone is stronger than concrete.
    • The strongest bone in your body is the femur (thighbone), and it's hollow!                             
    Blood Facts
    • Two million red blood cells die every second.
    • There are approximately 100,000 miles of blood vessels in the human body.
    • Seven percent of a humans body weight is made up of blood.
    • In the early nineteenth century some advertisements claimed that riding the carousel was good for the circulation of blood.
    • Each day 400 gallons of recycled blood are pumped through the kidneys.
    • By donating just one pint of blood, four lives can be saved.
    • Blood is such a good stain that Native Americans used it for paint.
    • The kidneys filter over 400 gallons of blood each day.
    • The average life span of a single red blood cell is 120 days.
    • Blood accounts for about 8% of a human's body weight.
    • A woman has approximately 4.5 liters of blood in her body, while men have 5.6 liters.
    • Your blood takes a very long trip through your body. If you could stretch out all of a human's blood vessels, they would be about 60,000 miles long. That's enough to go around the world twice.
    • Half your body’s red blood cells are replaced every seven days.
    • If all the blood vessels in your body were laid end to end, they would reach about 60,000 miles.
    Eyes Facts
    • We should never put anything in or near our eyes, unless we have a reason to use eye drops. We would only do that if our doctor or parent told us to use them.
    • Blinking helps to wash tears over our eyeballs. That keeps them clean and moist. Also, if something is about to hit our eye, we will blink automatically.
    • Our body has some natural protection for our eyes. Our eyelashes help to keep dirt out of our eyes. Our eyebrows are made to keep sweat from running into our eyes.
    • Our eyes are very important to us, and we must protect them. We don't want dirt, sand, splinters or even fingers to get in our eyes. We don't want our eyes to get scratched or poked. That could damage our sight!
    • The study of the iris of the eye is called iridology.
    • The shark cornea has been used in eye surgery, since its cornea is similar to a human cornea.
    • The number one cause of blindness in adults in the United States is diabetes.
    • The eyeball of a human weighs approximately 28 grams.
    • The eye of a human can distinguish 500 shades of the gray.
    • The cornea is the only living tissue in the human body that does not contain any blood vessels.
    • The conjunctiva is a membrane that covers the human eye.
    • Sailors once thought that wearing a gold earring would improve their eyesight.
    • Research has indicated that a tie that is on too tight cam increase the risk of glaucoma in men.
    • People generally read 25% slower from a computer screen compared to paper.
    • Men are able to read fine print better than women can.
    • In the United States, approximately 25,000 eye injuries occur that result in the person becoming totally blind.
    • All babies are colour blind when they are born.
    • A human eyeball weighs an ounce.
    • If the lens in our eye doesn't work quite right, we can get glasses to help us see. Glasses have lenses in them that work with our eye's own lens to help us see better.
    • Babies' eyes do not produce tears until the baby is approximately six to eight weeks old.
    • The reason why your nose gets runny when you are crying is because the tears from the eyes drain into the nose.
    • The most common injury caused by cosmetics is to the eye by a mascara wand.
    • Some people start to sneeze if they are exposed to sunlight or have a light shined into their eye.
    • The highest recorded speed of a sneeze is 165 km per hour.
    • It is impossible to sneeze with your eyes open.
    • The space between your eyebrows is called the Glabella.
    • Inside our eye, at the back, is a part called the "retina." On the retina are cells called "rods" and "cones." These rods and cones help us to see colors and light.
    • Just behind the pupil is a lens. It is round and flat. It is thicker toward the middle.
    • Over the front of our eye is a clear covering called the "conjunctiva."
    • The white part of our eye is called the "sclera." At the front, the sclera becomes clear and is called the "cornea."
    • Around the pupil is a colored muscle called the "iris." Our eyes may be BLUE, BROWN, GREEN, GRAY OR BLACK, because that is the color of the iris.
    • Our eyes have many parts. The black part on the front of our eye is called the "pupil." It is really a little hole that opens into the back part of our eyes.
    • Your eyes blinks over 10,000,000 times a year!
    Mouth Facts
    • In a month, a fingernail grows an eighth of an inch.
    • People whose mouth has a narrow roof are more likely to snore. This is because they have less oxygen going through their nose.
    • While sleeping, one man in eight snores, and one in ten grinds his teeth.
    • It takes food seven seconds to go from the mouth to the stomach via the esophagus.
    Tongue Facts
    • Close to fifty percent of the bacteria in the mouth lives on the surface of our tongue.
    • There are approximately 9,000 taste buds on the tongue.
    • Your tongue has 3,000 taste buds.
    • 85% of the population can curl their tongue into a tube.                                                              
    Hair Facts
    • On average, a man spends about five months of his life shaving.
    • On average, a hair strand's life span is five and a half years.
    • On average redheads have 90,000 hairs. People with black hair have about 110,000 hairs.
    • Next to bone marrow, hair is the fastest growing tissue in the human body.
    • In a lifetime, an average man will shave 20,000 times.
    • Humans have about the same number of hair follicles as a chimpanzee has.
    • Hair will fall out faster on a person that is on a crash diet.
    • The average human head weighs about eight pounds.
    • The reason why some people get a cowlick is because the growth of their hair is in a spiral pattern, which causes the hair to either stand straight up, or goes to a certain angle.
    • The reason why hair turns gray as we age is because the pigment cells in the hair follicle start to die, which is responsible for producing "melanin" which gives the hair colour.
    • The big toe is the foot reflexology pressure point for the head.
    • The loss of eyelashes is referred to as madarosis.
    • The longest human beard on record is 17.5 feet, held by Hans N. Langseth who was born in Norway in 1846.
    • The fastest growing tissue in the human body is hair.
    • The average human scalp has 100,000 hairs.
    • Hair and fingernails are made from the same substance, keratin.
    • Hair is made from the same substance as fingernails.
    • Eyebrow hair lasts between 3-5 months before it sheds.
    • The first hair dryer was a vacuum cleaner that was used for drying hair.
    • A Russian man who wore a beard during the time of Peter the Great had to pay a special tax.
    • Everyday approximately 35 meters of hair fiber is produced on the scalp of an adult.
    • Brylcreem, which was created in 1929, was the first man's hair product.
    • Ancient Egyptians used to think having facial hair was an indication of personal neglect.
    • A survey done by Clairol 10 years ago came up with 46% of men stating that it was okay to color their hair. Now 66% of men admit to coloring their hair.
    • A lifespan of an eyelash is approximately 150 days.
    Diseases Facts
    • People that use mobile phones are 2.5 time more likely to develop cancer in areas of the brain that are adjacent to the ear they use to talk on the mobile phone.
    • Over 90% of diseases are caused or complicated by stress.
    • Over 436,000 U.S. Troops were exposed to depleted uranium during the first Gulf war.
    • On average, 90% of the people that have the disease Lupus are female.
    • Many cancer patients that are treated with chemotherapy lose their hair. For some when the hair grows back, it can grow back a different colour, or be curly or straight.
    • Diabetes is the fourth leading cause of death in the U.S., accounting for about 180,000 deaths per year.
    • Chances of a women getting breast cancer are increased by excessive use of alcohol.
    • A popular superstition is that if you put a piece of bread in a baby's crib, it will keep away diseases.
    • A person that is struck by lightning has a greater chance of developing motor neurons disease.
    • Every year in the U.S., there are 178,000 new cases of lung cancer.
    • Every three minutes a woman is diagnosed with breast cancer.
    • Asthma affects one in fifteen children under the age of eighteen.
    • Every eleven minutes in the U.S., a woman dies of breast cancer.
    • Due to eating habits in the USA, one in three children born in the year 2000 have a chance of getting type II diabetes.
    • The oldest known disease in the world is leprosy.
    • The number one cause of rabies in the United States are bats.
    • Coughing can cause air to move through your windpipe faster than the speed of sound — over a thousand feet per second!
    • A headache and inflammatory pain can be reduced by eating 20 tart cherries.
    • The incidents of immune system diseases has increased over 200% in the last five years.
    • The flu pandemic of 1918 killed over 20 million people.
    • Each year in America there are about 300,000 deaths that can be attributed to obesity.
    • Every three days a human stomach gets a new lining.
    • The first owner of the Marlboro Company, Wayne McLaren, died of lung cancer.
    • Soldiers disease is a term for morphine addiction. The Civil War produced over 400,000 morphine addicts.
    • Rocky Mountain spotted fever is a disease caused by ticks.
    • A person afflicted with hexadectylism has six fingers or six toes on one or both hands and feet.
    • A study indicates that smokers are likely to die on average six and a half years earlier than non-smokers.
    • A person who smokes a pack of cigarettes a day will on average lose two teeth every ten years.
    • Lady Peseshet is known to be the world's first known female physician. She practiced during the time of the pyramids, which was the fourth dynasty.
    • The DNA of humans is closer to a rat than a cat.
    • Teenage suicide is the second cause of death in the state of Wisconsin.
    • Teenage cosmetic surgeries nearly doubled in the USA between 1996 and 1998.
    • Studies indicate that weightlifters working out in blue gyms can handle heavier weights.
    • Studies indicate that listening to music is good for digestion.
    • Studies indicate that epileptic patients that listen to Mozart's Piano Sonata can dramatically decrease their chance of a seizure.
    • Lack of sleep can affect your immune system and reduce your ability to fight infections.
    • It takes about three hours for food to be broken down in the human stomach.
    • Over 40 million Americans have chronic bad breath.
    • Carbon monoxide can kill a person in less than 15 minutes.
    • Fourteen people die each day from asthma in the United States.
    • Every day the human stomach produces about 2 liters of hydrochloric acid.
    • Nearly half of all Americans suffer from symptoms of burnout.In humans, the epidermal layer of skin, which consists of many layers of skin regenerates every 27 days.
    • Native Americans used to use pumpkin seeds for medicine.
    • In ancient Egypt, doctors used jolts from the electric catfish to reduce the pain of arthritis.
    • The lining of the a person's stomach is replaced every 36 hours.
    • The purpose of tonsils is to destroy foreign substances that are swallowed or breathed in.
    • In the United States, poisoning is the fourth leading cause of death among children.
    • The risk of cardiovascular disease is twice as high in women that snore regularly compared to women who do not snore.
    • The stomach of an adult can hold 1.5 liters of material.
    • The stomach can break down goat's milk faster than the milk of a cow.
    • The smoke that is produced by a fire kills more people than a burn does because of carbon monoxide and other dangerous gases.
    • It has been medically been proven that laughter is an effective pain killer.
    • Influenza caused over twenty-one million deaths in 1918.
    • In a year, there are 60,000 trampoline injuries that occur in the U.S.
    • Even if you eat food standing on your head, the food will still end up in your stomach.
    • A person infected with the SARS virus, has a 95-98% chance of recovery.
    • 3000 children die every day in Africa because of malaria.                                                           
    Pregnancy Facts
    • The world's first test tube twins are Stephen and Amanda Mays born June 5, 1981.
    • Some people drink the urine of pregnant women to build up their immune system.
    • The first known contraceptive was crocodile dung, used by Egyptians in 2000 B.C.
    • Every day, over 1,300 babies are born prematurely in the USA.
    • During pregnancy, the average woman's uterus expands up to five hundred times its normal size.
    • Changing a cat's litter box can be dangerous to pregnant women, as cat feces sometimes carry a parasite that can cause harm to the developing baby.
    • A pregnant woman's dental health can affect her unborn child.
    • May babies are on avearge 200 grams heavier than babies born in other months.
    • When a women is pregnant, her senses are all heightened.
    • Studies show that couples that smoke during the time of conception have a higher chance of having a girl compared to couples that do not smoke.
    Sex Facts
    • There are approximately 100 million acts of sexual intercourse each day.
    • The sperm count of an average American male compared to thirty years ago is down thirty percent.
      An adult esophagus can range from 10 to 14 inches in length and is one inch in diameter.
    • Men sweat more than women. This is because women can better regulate the amount of water they lose.
    • The average amount of time spent kissing for a person in a lifetime is 20,160 minutes.
    • The average adult has approximately six pounds of skin.
    • Infants spend more time dreaming than adults do.
    • In one day, adult lungs move about 10,000 liters of air.
    • The condom made originally of linen was invented in the early 1500's. Casanova, the womanizer, used linen condoms.
    • Sex burns about 70-120 calories for a 130 pound woman, and 77 to 155 calories for a 170 pound man every hour.
    • Impotence is grounds for divorce in 26 U.S. states.
    • There are approximately 45 billion fat cells in an average adult.
    • Kissing can aid in reducing tooth decay. This is because the extra saliva helps in keeping the mouth clean.
    • During the female orgasm, endorphines are released, which are powerful painkillers. So headaches are in fact a bad excuse not to have sex.
    • During World War II, condoms were used to cover rifle barrels from being damaged by salt water as the soldiers swam to shore.
    • According to psychologists, the shoe and the foot are the most common sources of sexual fetishism in Western society.
    • A kiss for one minute can burn 26.                                                                                                   
    Other Human Body Facts
    • The Gastric Flu can cause projectile vomiting.
    • The Dutch people are known to be the tallest people in Europe.
    • Studies have shown that the scent of Rosemary can help in better mental performance and make individuals feel more alert.
    • Some brands of toothpaste contain glycerin or glycerol, which is also an ingredient in antifreeze.
    • Soaking beans for twelve hours in water before they are cooked can reduce flatulence caused by beans.
    • Scientists say that babies that are breastfed are more likely to be slimmer as adults than those that are not breastfed.
    • Scientists have determined that having guilty feelings may actually damage your immune system
      Research has indicated that approximately eleven minutes are cut off the life of an average male smoker from each cigarette smoked.
    • People have the tendency to chew the food on the side that they most often use their hand.
    • Over 600,000 people died as a result of the Spanish influenza epidemic.
    • Only one out of every three people wash their hands when leaving a public bathroom.
    • One ragweed plant can release as many as a million grains of pollen in one day.
    • One out of 20 people have an extra rib.
    • One average, men spend 60 hours a year shaving.
    • On average, falling asleep while driving results in 550 accidents per day in the United States.
    • On average, a person has two million sweat glands.
    • On average, Americans spend 33% of their life sleeping.
    • On average a person passes gas 14 times a day.
    • On average 1,668 gallons of water are used by each person in the United States daily.
    • Nerve impulses for muscle position travel at a speed of up to 390 feet per second.
    • Nerve cells can travel as fast as 120 meters per second.
    • Mummy powder was once thought to be a cure for all remedies. English men used to carry the powder with them in a tiny bag wherever they went.
    • Men in their early twenties shave an average of four times a week.
    • Medical research has found substances in mistletoe that can slow down tumor growth.
    • Medical reports show that about 18% of the population are prone to sleepwalking.
    • Manicuring the nails has been done by people for more than 4,000 years.
    • Left-handed people are better at sports that require good spatial judgment and fast reaction, compared to right-handed individuals.
    • Ironically, when doctors in Los Angeles, California went on strike in 1976, the daily number of deaths in the city dropped 18%.
    • In the United States, 8.5 million cosmetic surgical and non-surgical procedures were done in the year 2001.
    • People with darker skin will not wrinkle as fast as people with lighter skin.
    • People with allergies can lower allergy reactions by laughing.
    • People who meet their calcium need reduce their risk of developing kidney stones.
    • People that smoke have 10 times as many wrinkles as a person that does not smoke.
    • People still cut the cheese shortly after death.
    • People over the age of fifty will start to lose their dislike for foods that taste bitter.
    • People of Ancient China believed that swinging your arms could cure a headache.
    • The average weight of a newborn baby is 7 lbs. 6 oz. For a triplet baby it is 3 lbs. 12 oz.
    • The average person spends two weeks of their life kissing.
    • The average person falls asleep in about 12 to 14 minutes.
    • There are approximately one hundred million people in the United States that have a chronic illness.
    • There are approximately 60 muscles in the face.
    • There are 50% more males that are left handed compared to females.
    • There are 400 species of bacteria in the human colon.
    • There are 10 million bacteria at the place where you rest your hands at a desk.
    • In a lifetime, an average human produces 10,000 gallons of saliva.
    • In a lifetime, an average driver will release approximately 912 pints of wind inside a car.
    • In Canada, men are three times more likely than women to have seen a doctor in the last year.
    • In 1832, in Paisley, Scotland the first municipal water filtration works was opened.
    • Humans breathe in and out approximately one litre of air in ten seconds.
    • Girls have more tastebud than boys.
    • From the age of thirty, humans gradually begin to shrink in size.
    • Flu shots only work about 70% of the time.
    • Gases that build up in your large intestine cause flatulence. It usually takes about 30 to 45 minutes for these gases to pass through your system.
    • Fat is important for the development of children and normal growth.
    • Every day, the average person swallows about a quart of snot.
    • Eighty percent of 10 year old girls in the USA go on a diet.
    • Air is passed through the nose at a speed of 100 miles per hour when a person sneezes.
    • About twenty-five percent of the population sneeze when they are exposed to light.
    • A yawn usually lasts for approximately six seconds.
    • Children who are breast fed tend to have an IQ seven points higher than children who are not.
    • Children grow faster in the springtime than any other season during the year.
    • Eating chocolate three times a month helps people live longer as opposed to people who overeat chocolate or do not eat chocolate at all.
    • Constipation is caused when too much water is absorbed in the large intestine and poops become dry.
    • A ear trumpet was used before the hearing aid was invented by people who had difficulty hearing.
    • The average human dream lasts only 2 to 3 seconds.
    • The average person has at least seven dreams a night.
    • Bile produced by the liver is responsible for making your feces a brownish, green colour.
    • It takes more muscles to frown than it does to smile.
    • By the time you are 70 you will have easily drunk over 12,000 gallons of water.
    • A man named Charles Osborne had the hiccups for approximately sixty-nine years.
    • The average person walks the equivalent of twice around the world in a lifetime.
    • The average person laughs about 15 times a day.
    • The vocabulary of the average person consists of 5,000 to 6,000 words.
    • About 10% of the world's population is left-handed.