Dropping a Bowling Ball and a Feather Inside a Vacuum Chamber

One of the ways in which Galileo revolutionized the world of physics was by challenging the Aristotelian notion that heavier objects fall faster than lighter ones. One apocryphal story claims he accomplished this by dropping various objects of different masses and densities from the top of the Leaning Tower of Pisa and measuring how long that took, afterward arguing that any differences could be explained by air resistance.

During the Apollo 15 expedition to the moon, one of the astronauts dropped a hammer and a feather at the same time and, without any air resistance on the moon surface, they both fell at the same speed. But the footage was a bit grainy. Luckily, video resolution has gotten a lot better over time, as well as our ability to create large vacuum chambers where we can recreate this famous experiment in a much more dramatic and impressive manner, and without having to travel to the moon surface. Oh, and now we also have Brian Cox to guide us through some of the scientific significance of this simple demonstration.