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What do you know about water? What should you know about water? What are various forms/shapes of water? What should you know about drinking water quality? What is the percentage of world population that has access to drinking tap water at home or home office? What are the human uses of water? How has water been described? What is Water? How much water is there on Earth? Why can't we manufacture water? If water is made up of hydrogen and oxygen, why can't we breathe underwater? What do you know about water? What should you know about water? What are various forms/shapes of water? Solid Liquid Gas Drinking water quality What should you know about drinking water quality? What is the percentage of world population that has access to drinking tap water at home or home office? Human uses of water What are the human uses of water? Description of water How has water been described? What is Water? Water is very important for life. We need water to drink, to wash our hands, to cook, to water plants and many other things. Water exists in three states- solid, liquid, and gaseous. Liquid water is found in many places. You see liquid water coming out of the faucet, when it rains, and running in a river. Pure liquid water is free of salt, rocks, soil, and garbage. Ice, snow, and frost are examples of water in the solid state. Liquid water freezes at 0 degrees Celsius. Celsius is scale that measures temperature. What instrument do you use to measure temperature? Winter is a season that you see a lot of solid water. Other examples of solid water are ice cubes, icicles, ice on a skating rink. Water evaporates to turn into a gas. Water can evaporate or disappear with the help of heat. Changes in temperature can increase the rate or how long it takes water to evaporate. Evaporate means to disappear. Water can evaporate from soil. It evaporates off wet clothes hanging on a clothesline. Plants release water vapor into the air. We breathe out water vapor. How much water is there on Earth? There's a whole lot of water on Earth! Something like 326,000,000,000,000,000,000 gallons (326 million trillion gallons) of the stuff (roughly 1,260,000,000,000,000,000,000 liters) can be found on our planet. This water is in a constant cycle -- it evaporates from the ocean, travels through the air, rains down on the land and then flows back to the ocean. The oceans are huge. About 70 percent of the planet is covered in ocean, and the average depth of the ocean is several thousand feet (about 1,000 meters). Ninety-eight percent of the water on the planet is in the oceans, and therefore is unusable for drinking because of the salt. About 2 percent of the planet's water is fresh, but 1.6 percent of the planet's water is locked up in the polar ice caps and glaciers. Another 0.36 percent is found underground in aquifers and wells. Only about 0.036 percent of the planet's total water supply is found in lakes and rivers. That's still thousands of trillions of gallons, but it's a very small amount compared to all the water available. The rest of the water on the planet is either floating in the air as clouds and water vapor, or is locked up in plants and animals (your body is 65 percent water, so if you weigh 100 pounds, 65 pounds of you is water!). There's also all the soda pop, milk and orange juice you see at the store and in your refrigerator… There's probably several billion gallons of water sitting on a shelf at any one time! Why can't we manufacture water? Water is made of two hydrogen atoms attached to an oxygen atom. This seems like pretty basic chemistry, so why don't we just smash them together and solve the world's water ills? Theoretically, this is possible, but it would be an extremely dangerous process, too. To create water, oxygen and hydrogen atoms must be present. Mixing them together doesn't help; you're still left with just separate hydrogen and oxygen atoms. The orbits of each atom's electrons must become linked, and to do that we must have a sudden burst of energy to get these shy things to hook up. Since hydrogen is extremely flammable and oxygen supports combustion, it wouldn't take much to create this force. Pretty much all we need is a spark -- not even a flame -- and boom! We've got water. The hydrogen and oxygen atoms' electrons' orbits have been conjoined. But we also have an explosion and -- if our experiment was big enough, a deadly one. The ill-fated blimp, the Hindenburg, was filled with hydrogen to keep it afloat. As it approached New Jersey on May 6, 1937, to land after a trans-Atlantic voyage, static electricity (or an act of sabotage, according to some) caused the hydrogen to spark. When mixed with the ambient oxygen in the air, the hydrogen exploded, enveloping the Hindenburg in a ball of fire that completely destroyed the ship within half a minute. There was, however, also a lot of water created by this explosion. To create enough drinking water to sustain the global population, a very dangerous and incredibly large-scale process would be required. Still, over a century ago the thought of an internal combustion engine -- with its controlled repeated explosions -- seemed dangerously mad. And as water becomes scarcer, the process of joining hydrogen atoms to oxygen atoms may become more attractive than it is currently. Necessity, after all, is the mother of invention. But there are safer ways of creating water out of thin air, and projects to do just that are already underway. Read the next page to learn about a few mad scientists who may end up solving the world's impending water crisis. If water is made up of hydrogen and oxygen, why can't we breathe underwater? One thing about chemicals is that, once they react in certain ways, they form compounds that are nothing like the original elements. For example, if you react carbon, hydrogen and oxygen together one way you get glucose (C6H12O6) (see How Food Works). If you react them together another way you get vinegar (C2H4O2). If you react them another way you get fat (see How Fat Works). If you react them another way you get ethanol (C2H5OH). Glucose, fat, ethanol and vinegar are nothing like each other, but they are all made from the same elements. In the case of hydrogen and oxygen gas, if you react them together one way you get liquid water (H2O). The reason we cannot breathe liquid water is because the oxygen used to make the water is bound to two hydrogen atoms, and we cannot breathe the resulting liquid. The oxygen is useless to our lungs in this form. The oxygen that fish breathe is not the oxygen in H2O. Instead, the fish are breathing O2 (oxygen gas) that is dissolved in the water. Many different gases dissolve in liquids, and we see an example all the time in carbonated beverages. In these beverages, there is so much carbon dioxide gas dissolved in water that it rushes out in the form of bubbles. Fish "breathe" the dissolved oxygen out of the water using their gills. It turns out that extracting the oxygen is not very easy -- air has something like 20 times more oxygen in it than the same volume of water. Plus water is a lot heavier and thicker than air, so it takes a lot more work to move it around. The main reason why gills work for fish is the fact that fish are cold-blooded, which reduces their oxygen demands. Warm-blooded animals like whales breath air like people do because it would be hard to extract enough oxygen using gills. Humans cannot breathe underwater because our lungs do not have enough surface area to absorb enough oxygen from water, and the lining in our lungs is adapted to handle air rather than water. However, there have been experiments with humans breathing other liquids, like fluorocarbons. Fluorocarbons can dissolve enough oxygen and our lungs can draw the oxygen out -- see the last link below for some fascinating details! |
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Lake Ocean River |
| Seawater Desalination |
| Water (Hydraulic Wing/PHE) |