Galileo discovered in 15th century that any object falling to earth ,falls at the same rate of acceleration. He mentioned that a cannon ball and feather if dropped from the same height , will touch the ground at the same time, in the absence of air resistance. He found it difficult to explain it.
It is one of the most famous experiments in all of science history, but there’s significant doubt about whether it actually took place. Did Galileo drop objects of differing mass from the Leaning Tower of Pisa in 1589 to demonstrate the theories proposed in his unpublished text De motu (“Of Motion”)? Rice University’s Galileo Project notes that scholars have long thought Galileo’s references to experiments he conducted “were only rhetorical devices.” As PBS’s NOVA writes, “it’s the kind of story that’s easy to imagine, easy to remember, but whether he ever performed the experiment at the tower is debatable.” That’s not to say Galileo didn’t test any of his ideas while he taught at the University of Pisa during 1589 and 1592, only that his most famous theory about the effects of gravity on free-falling objects rests mainly on a conceptual thought experiment.
In fact, it would have been impossible for Galileo to fully demonstrate his theory because of the effects of air resistance. Subtract the atmosphere, however, and we can easily confirm Galileo’s hypothesis that any two objects, regardless of weight, shape, or material of composition, will fall at exactly the same rate when dropped.
Four centuries later with the current technology, watch as Brian Cox travels to the world’s biggest vacuum chamber at NASA’s space power facility, Ohio to experimentally demonstrate the theory. It is a visual treat to watch this video.
Programme website: http://www.bbc.co.uk/programmes/p0276q28 Brian Cox visits NASA’s Space Power Facility in Ohio to see what happens when a bowling ball and a feather are dropped together under the conditions of outer space.