WHAT IS STORM?

Even though man has become a powerful creature, able to control mighty forces, nature can still strike terror into his heart when she ships up a storm! What is storm?

Whenever there is something taking place in the weather of a violent nature, it is a storm. At sea, a storm may be strong wind or gale. Inland, a storm usually means there is weather situation that is marked by heavy rain, and often by lighting, thunder and strong winds.

A storm in the latitudes where the United States lies usually covers an area hundreds of miles across. It represents vast circular whirls of air roaring about a central point of low atmospheric pressure.

Such storms begin where cold dry masses of air moving southward from Arctic regions are met by warm moist air masses moving northward from the tropics. At certain places, great tongues of the warm air thrust their way into cold. The tip of such a warm air tongue becomes a spot a low atmospheric pressure, toward which the winds blow, and the storm area develops around it.

Where the cold and warm air masses actually meet, they mix only slightly. The lighter warm air climbs up and over the cold air along a sloping surface. This cools the warm moist air, it becomes saturated, clouds form, and the result may be rain or snow.

In the Northern Hemisphere, the earth's rotation causes the winds to be deflected toward the right, so the "whirl" of the storm is counterclockwise. In fact, it's like a whirlwind on a huge scale.

Typhoons and hurricanes north of the Equator usually originate in late summer or fall over warm tropical water. They move westward and northwestward in a path that curves to the right. A tornado is a violent whirlwind. It begins as a black, funnel-shaped cloud that accompanies a larger thunderstorm area. The tip of the funnel may be only a few hundred feet wide but it destroys whatever it touches. The destruction is caused by the terrific speed of the wind and the terrific reduction in atmospheric pressure. Walls of houses are sucked out and the buildings collapse! Tornadoes are so destructive that in regions where they occur often, people have built special places to hide from their danger.

HOW DOES WATER CHANGE TO ICE?

If you've ever noticed a pond, lake or river freeze, you've seen a sheet of ice begin to form over the top of the water.

Do you realize that if ponds, lakes and rivers froze from the bottom up, instead of from the top down, many important things about our life would be quite different? Not only would it change the climate of the world, but certain creatures who live in the water would disappear altogether!

Here is how the water in a pond changes into ice: When the air above the pond grows cold, it cools off the top layer of water, too. This coldness makes the water heavier than the warmer layers underneath and the cold water sinks down. This process goes on and on until all the water in the pond has reached a temperature of about 39 degrees Fahrenheit.

But our temperature is still dropping! When the top layer of water becomes colder than 39 degrees, it remains on top. The reason is that water cooled to below 39 degrees actually becomes lighter!

We now have the top layer of water ready to start freezing. So when the temperature remains at the freezing point of 32 degrees, or if it goes below that, tiny crystals begin to form.

Each of these crystals has six rays, or points. As they join together they form ice and soon a whole sheet of ice appears on top of the water. Sometimes the ice is clear, sometimes its cloudy. Why? The reason is that when each drop of water freezes, it sets free a tiny bubble of air. This bubble sticks to the arms of the crystal. As more crystals form, the bubble caught and we have cloudy ice.

If the water under the ice is moving, the little air bubbles are grouped together into clear ice.

Water is one of the few substances that do not shrink when changed from liquid so solid. When water is frozen into ice it expends by one-ninth, so that nine quarts of water give you ten quarts of solid ice! When automobile radiators and water lines crack in winter, it's because the water freezes and there is no room for the ice!