The Science Behind Why a Feather and a Coin Dropped in Vacuum Fall at The Same Time

You have likely heard of Galileo's famous "falling bodies" experiment. It's one of the most well-known physics experiments out there and consists of Galileo attempting to demonstrate that the rate of falling of a body is independent of its mass by dropping objects from the top of the leaning tower of Pisa. 

It was perhaps most famously recreated at the end of the Apollo 15 moonwalk when commander David Scott held a hammer and a feather on the lunar surface and dropped them both at the same time. Do you know what happened next? They hit the ground at the same time.

YouTuber The Action Lab illustrates this same principle by using a vacuum chamber, a feather, and a coin. "In this video, I show you what happens when you drop a feather and a coin in a vacuum chamber. Then I show you what happens if you drop a golf ball and the moon on the earth at the same time from the same distance. I talk about inertia and how things always fall at the same acceleration no matter what their mass is," explains the YouTuber in his video's about section.

Want to know exactly what inertia is? Then watch this well-done clip.