GALILEO AND ARISTOTLE G104

 GALILEO AND ARISTOTLE

About 2,300 years ago, there lived in Greece a great thinker named Aristotle. He observed that feathers fell to the ground slowly, while stones fell much faster. He thought it over carefully and concluded that heavy objects always fell faster than light ones. His conclusion certainly sounded reasonable. But we now know that it is not true.

In those days people seldom did experiments to test their ideas. When they observed anything that happened, they thought about it and then drew a conclusion. Once Aristotle had made up his mind that heavy objects always fell faster than light objects, he taught it as a truth to his students. And because he was Aristotle, the great thinker, no one questioned his idea for almost 2,000 years.

Then, almost 400 years ago, an Italian scientist named Galileo began to question Aristotle's theory of falling objects. He was not ready to believe something just because Aristotle said so. He decided to do some experiments to test Aristotle's theory.

Galileo lived in the city of Pisa, where there is a leaning tower about 180 feet high. From the top of the tower Galileo dropped a light ball and a heavy ball at exactly the same time. They both fell at about the same speed and hit the ground together. He tried the experiment again and again. Every time he got the same result. At last, he decided that he had found the truth about falling objects. As we know now, heavy objects and light objects fall at the same speed unless air holds them back. A feather falls slower than a stone only because the air holds the feather back more than it does the stone.

When Galileo told people of his discovery, no one would believe him. But Galileo was not discouraged. He went on doing experiments to test the truth of other old ideas. He built a telescope through which he could study the skies. He collected facts that proved the earth and all the other planets move around the sun.

Today we praise Galileo and call him one of the founders of modern science. He observed things carefully and never took anything for granted. Instead, he did experiments to test and prove an idea before he was ready to accept it.

An interesting experiment was done on the moon in July, 1971. One of the US astronauts who made the first deep space walk on the moon dropped a hammer and a feather together. They both landed on the surface of the moon at the same time. This experiment proved that Galileo's theory of falling objects is true.