Apollo 15 Hammer and Feather drop test Credit NASA
All falling objects fall the same when under the same conditions… that is so long as no outside force is exerted on it. So two objects dropped from the same altitude, one a feather and hammer will fall equally. Don’t believe me? NASA tested it on the Moon. During Apollo 15 moon walk, Commander David Scott performed a live demonstration for the television cameras. Commander Scott held out a geologic hammer and a Falcon feather and dropped them at the same time. Because there is not an atmosphere on the Moon, they were essentially in a vacuum. With no air resistance force, the feather fell at the same rate as the hammer.
On Earth, and any other planet with an atmosphere, air acts as a resistance force for an object moving through it. We can get more air resistance force by increasing the surface area.
From the Apollo 15 Report:
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(* the 0.03-kg value is too high, typical feathers have masses between 0.0003 and 0.003 kg (0.3 – 3 grams), this may be due to a typo in the report.)
Apollo 15 Hammer and Feather experiment: Credit NASA
