Sharon Borror, age 10, of Muncie, Ind., for her question:
Exactly how much water is in the sea?
It is fun to scoop pails of sea water onto the beach. But if you scooped all day, the big sea would not become smaller. It has so much water that it would not miss a million pailfuls. No one has measured it pail by pail, but the experts have estimated the amount of water in the ocean.
No one can tell the exact number of drops in the vast ocean, but an expert can write down a huge figure and tell you that this is more or les& the correct number. He cannot be quite surf; so his huge number may have a few billion drops too many or too few. If you want to know how the experts figured it out, you may have to strain your brains.
Let's imagine a tank big enough to hold all the waters o€ the seas. Let's make our imaginary tank a mile wide on each side and long enough to reach to the moon. But this tank would not be long enough. In order to hold all the watery ocean, a milt wide tank would have to be 330 million miles long. It would be long enough to reach to the moon and back more than 500 times, plus a few whirls around the world. If we wanted to keep our imaginary tank of sea water on earth, we could twine it more than 10,000 t1me8 around the equator.
It is impossible to measure and count all the drops one by one, but experts can figure roughly the amount of water needed to fill the deep ocean basins. It takes a gallon to fill an ordinary pail, but it takes many gallons to fill a pool because the hollow is bigger. When experts know the size of the hollow ocean beds, they can figure how much water is needed to fill them to sea level.
This amount of water is estimated to be 330 million cubic miles. It is enough to fill 330 million square tanks, each one a mile high and a mile wide on every side. This figuring sounds simple, but the job of measuring the size of the sea's hollows calls for lots of patient work. We must learn the ocean width and depth at every point and we still do not have all these details. Hence, we can give only an estimate of the water, and the latest figure may be a little too big or a little too small.
More than two thirds of our world is covered by seas, and if our tallest mountain were dunked in the deepest part of the ocean, its peak would be a mile below the waves. If a giant bulldozer could level the land and the bumpy ocean beds, the seas would slop all over the continents. Our whole planet would be under 12,000 feet of water. All the solid ground would be more than two miles below the waves.