If you drop a feather and a hammer, will they hit the ground at the same time?
Yes, on the moon they will (but not on Earth due to air resistance).
A famous experiment proved this where an astronaut dropped a feather and a hammer on the moon.
0:00 Well, in my left hand, I have a feather; in my right hand, a hammer. And I guess one of the reasons we got here today was because of a gentleman named Galileo, a long time ago, who made a rather significant discovery about falling objects in gravity fields. And we thought where would be a better place to confirm his findings than on the Moon? And so we thought we’d try it here for you. The feather happens to be, appropriately, a falcon feather for our Falcon.
0:32 And I’ll drop the two of them here and, hopefully, they’ll hit the ground at the same time.
And they did.
0:37 Both were released simultaneously from the same height (1.6m) and hit the lunar surface simultaneously, as predicted by Galileo a long time ago but never tested in a vaccuum before.
|Aluminum geological hammer
Fun fact: Later investigations found that the feather may have been extracted from the wing of a female gyrfalcon.
During the Apollo 15 mission, David Scott did an experiment by dropping a hammer and a falcon feather at the same time. Both hit the ground at the same time. Why? According to the principle of relativity, without air resistance, two objects of different weight will hit the ground at the same time.
Scott’s use of a hammer and a feather validated Galileo’s theory that when there is no air resistance, objects fall at the same rate due to gravity regardless of their mass.
“During the final minutes of the third extravehicular activity, a short demonstration experiment was conducted. A heavy object (a 1.32-kg aluminum geological hammer) and a light object (a 0.03-kg falcon feather) were released simultaneously from approximately the same height (approximately 1.6 m) and were allowed to fall to the surface. Within the accuracy of the simultaneous release, the objects were observed to undergo the same acceleration and strike the lunar surface simultaneously, which was a result predicted by well-established theory, but a result nonetheless reassuring considering both the number of viewers that witnessed the experiment and the fact that the homeward journey was based critically on the validity of the particular theory being tested.” – Joe Allen, NASA SP-289, Apollo 15 Preliminary Science Report, Summary of Scientific Results, p. 2-11