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Do this before you go to the field! Click on the tabs to at the top to see each experiment. [|Link to Thought Experiments on Galileo's Experiments]

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 * Galileo's experiment on falling objects

In the late 1500's, everyone knew that heavy objects fall faster than lighter ones. After all, Aristotle had said so. That an ancient Greek scholar still held such sway was a sign of how far science had declined during the dark ages.

Galileo Galilei, who held a chair in mathematics at the University of Pisa, was impudent enough to question the common knowledge. The story has become part of the folklore of science: he is reputed to have dropped two different weights from the town's Leaning Tower showing that they landed at the same time. His challenges to Aristotle may have cost Galileo his job, but he had demonstrated the importance of taking nature, not human authority, as the final arbiter in matters of science.

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 * Galileo's experiments with rolling balls down inclined planes

Galileo continued to refine his ideas about objects in motion. He took a board 12 cubits long and half a cubit wide (about 20 feet by 10 inches) and cut a groove, as straight and smooth as possible, down the center. He inclined the plane and rolled brass balls down it, timing their descent with a water clock — a large vessel that emptied through a thin tube into a glass. After each run he would weigh the water that had flowed out — his measurement of elapsed time — and compare it with the distance the ball had traveled.

Aristotle would have predicted that the velocity of a rolling ball was constant: double its time in transit and you would double the distance it traversed. Galileo was able to show that the distance is actually proportional to the square of the time: Double it and the ball would go four times as far. The reason is that it is being constantly accelerated by gravity.

Crease, Robert, and George Johnson. "Science's 10 most beautiful experiments." __Physics Animations__. New Your Times. 21 Mar. 2009 <[]>.

"Illuminations: Inclined Plane." __Illuminations: Welcome to Illuminations__. 21 Mar. 2009 <[]>.

"NASA -." __NASA -__. 21 Mar. 2009 <[]>.

"NOVA | Galileo's Battle for the Heavens | His Experiments |." __PBS__. 21 Mar. 2009 <[]>.

"Teachers' Domain: Galileo's Inclined Plane." __Teachers' Domain: Home__. 21 Mar. 2009 <[]>.