Meteorology is the field of science that studies the movements of weather all over our planet and in the atmosphere above it. Meteorologists use satellites out in space to track these changes and send the informationto numerous computers. The computers help to predict what the weather might be across the countryor near you. Did you ever notice how the sound of a train's horn changes as it approaches you and then goes on its way? Now imagine that the train is movingon a rainbow-colored track that starts out with a bluish color and then gradually becomes red. As the train passes you, it enters the red part of the track and moves away. Light and sound waves both look or sound different as something approaches or leaves them. Scientistscall this the Doppler effect. Astronomers use it to track the movement of stars through red and blue shifts. When severe thunderstorms are around, your local meteorologist uses a Doppler radar to see if strong winds are moving closer or father away from you.

What do you think causes the weather? If you said “the water in the oceans,” you would be on the right track. The main reason for this is the oceans store a lot of the heat that comes from the sun. Some parts of the ocean become warm enough to affect the weather on continents that are thousands of miles away. The sun also warms the continents, but when it gets dark, they get a lot colder. The difference in temperatures moves the air inland at night and then back out toward the ocean each day. One way to see this is by flying a kite. A kite should fly easily if you stand on the beach around sunset. Then you can check to see if the wind direction really does change.

Our Ever-Changing Earth

There's a reason people say, “If you don't like the weather today, wait till tomorrow.” Weather changes quickly, but the climate is usually unchanging. Or so it used to be. For fun ask your parents if the summers and the winters are warmer or colder than they used to be. A lot of the scientists who have studied the earth believe that the areas at the North and South Poles were flattened from the intense weight of the glaciers that used to cover much of the earth. Although no one wants another Ice Age, you might like a little more snow from time to time, so you can build an ice fort, skate, and ski. So why is the weather changing? You probably never thought that sunspots could cause so much trouble, but after a great deal of studying, it appears they can affect our weather! In the past, a decrease in sunspot activity may have loweredthe temperature on Earth, caused droughts, and increased the number of storms. At that time, Earth may have appeared to look more like the moon. It's possible that the weather caused by movements in Earth's new atmosphere caused the craters on its surfaceto be flattened. If you were to travel to the bottomof the Grand Canyon in Arizona, you could see layers of rock that were created billions of years ago when the earth was new. It's like taking a trip back through time. If you wanted to see what a crater on the moon looks like, you could visit a place called the Barringer Crater, which is located in northernArizona, or visit the Craters of the Moon National Monument in Idaho.