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Why things fall down

Galileo: the father of modern science

Galileo is widely considered to be one of the greatest scientists who ever lived. Galileo enjoyed trying to explain how nature works and he also enjoyed designing experiments that he could use to test his ideas.
In the video below, we see how he came up with one of his most famous theories. This idea was that if you drop two objects that have different masses, from the same height, they will hit the ground at the same time.

To test his theory, Galileo did a range of experiments. It is sometimes said that in one of these experiments, Galileo dropped two balls from the top of the leaning tower of Pisa. One ball was wooden and one was lead. Historians think this probably didn’t happen, although Galileo did, they say, suggest that this would be an exciting way to see his theory working in practice.

Interestingly, Galileo’s experiment was tried years later: Two balls were dropped from Pisa but the surprise was that the lead ball hit the ground first. Why? Galileo knew why. He had already predicted that this would happen. The force of gravity was not the only force at work in this instance. Air resistance also played a role and affected one ball more than the other.

A couple of hundred years later, a chance came for scientists to test Galileo’s theory in a place where there is no air.

In 1971, Commander David Scott (pictured right) from the Apollo 15 mission, put Galileo’s idea to the test. In front of a live television audience, in one hand, he held a hammer and in the other, a feather.

Scott dropped them at the same time … and scientists nodded with satisfaction. Just as Galileo had concluded hundreds of years before, it really is the case that two objects with different masses, dropped from the same height, will hit the ground together (as long as there’s no air!)

© 2011 LASAR (Learning about Science and Religion)