35.DOES THE AIR HAVE WEIGHT?
Most of us think of air as being “nothing,” but air is definitely “something,” if it is matter made up of certain gases. A gas does not have a definite size or shape, but it takes up space.
The great ocean of air that surrounds the earth and extends for many miles upward is attracted and held to the earth by gravity. Thus air has weight. And since air is everywhere about us, it adds weight to every object it fills. For example, there is a small amount of air in a volley ball. If you were to weigh two such balls, with the air let out of one of them, you would find it’s lighter than the other.
34.DO HURRICANES MOVE IN DEFINITE DIRECTIONS?
A storm or a hurricane seems such a wild, uncontrolled thing that it’s hard to believe it is following a definite path. Yet, as we know, when the hurricane season starts, the hurricanes are given names and their courses are often predicted very accurately!
In most parts of the world, most storms do move in definite directions. In the United States, for example, most big storms are vast circular whirls of air that rotate counterclockwise about a central point of low atmospheric pressure. The reason they rotate counterclockwise in the United States is that, as winds flow in toward the center of low pressure, the earth’s rotation deflects them toward the right (in the Northern Hemisphere).
33.WHY DOES THE MOON FOLLOW US WHEN WE DRIVE?
The moon doesn’t look as if it’s very far away, but its distance from the earth averages 239,000 miles. The diameter of the moon is 2,160 miles, or less than the distance across the United States. But when the moon is observed with a very large telescope, it looks as if it were only about 200 miles away.
Because the moon seems so close and big to us, we sometimes forget that 239,000 miles is quite a distance away. It is this great distance that explains why the moon seems to follow us when we drive in a vehicle and look up at it.
