Tuesday, November 04, 2014

Physics lesson

We all learned of Galileo's experiment from the Leaning Tower of Pisa in which he dropped two balls of different masses to test his hypothesis that the difference would not affect the time of transit to the ground.  The idea was that they were both subject to the same force of gravity and would therefore accelerate at the same rate.

Although his theory was correct, the problem with the story is that they did not actually arrive on the ground at the same time because. As noted in this Wikipedia article:

In Dava Sobel's biographical book Galileo's Daughter she recounts that the balls did not land at the same time:

The larger ball, being less susceptible to the effects of what Galileo recognized as air resistance, fell faster, to the great relief of the Pisan philosophy department.

So it is with great interest that we can witness a more controlled experiment.  Here on IFLScience:

You probably know that two objects dropped in a vacuum fall at the same rate, no matter the mass of each item. If you’ve never seen a demonstration of this, then you really should, because it’s incredible to watch.

Here is perhaps the perfect example, brought to us by physicist Brian Cox. He checked out NASA’s Space Simulation Chamber located at the Space Power Facility in Ohio. With a volume of 22,653 cubic meters, it’s the largest vacuum chamber in the world.

In this hypnotizing clip from the BBC, Cox drops a bowling ball and a feather together, first in normal conditions, and then after virtually all the air has been sucked out of the chamber. We know what happens, but that doesn’t stop it from being awesome, especially with the team’s ecstatic faces.

Here's the video. (You can start at 2:41 if you are impatient.)

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