David Scott does the feather hammer experiment on the moon | Science News
Why Physics Stack Exchange recommends it
Physics Stack Exchange answerers link it as a direct demonstration that, without air resistance, all objects fall at the same rate regardless of mass.
Recommended by 2 people across 2 different months, 2021 to 2024.
What it is
A 52-second clip from Apollo 15 in which astronaut David Scott drops a hammer and a falcon feather at the same time on the Moon. Both reach the surface together, showing that objects fall at the same rate in a vacuum regardless of mass. The footage is from NASA and is republished by Science News.
What people said
Recommends Adrian Howard · 2021-04 · Physics Stack Exchange · on “Does material (density) affect falling rate of objects?”
The cotton would have greater air resistance so it would fall slower. However, neglecting air resistance, all masses in the same gravitational field fall at the same rate. Near Earth's surface objects fall at about 9.8 meters per second squared, neglecting air resistance. Here is an interesting clip of a feather and a hammer being dropped on the Moon where there is negligible air resistance; [this video]
Recommends Gabriel Ybarra Marcaida · 2024-05 · Physics Stack Exchange · on “Gravitational attraction between two bodies and gravitational accelaration”
Newton's second law is $F=ma$ , where the force for the gravitational attraction in the surface of the earth is approximately $F=mg$ . This means that $$ ma = F = mg \implies \mathbf{a = g}. $$ Thus we see that the acceleration of any object caused by a gravitational field is independent of its mass . We can play the same game considering $$ F = \dfrac{GmM_{\text{earth}}}{r^2} \implies a = \dfrac{GM_{\text{earth}}}{r^2}, $$ to obtain the exact same conclusion. Thus two objects will take the same time to fall, independently of their mass. Be careful if you try this at home, because you have to also consider the drag force of the air, which will slow more the lighter object . If you try to dro
Cites ZeroTheHero · 2022-11 · Physics Stack Exchange · on “Chaos theory: What exactly drives the future outcome?”
Chaos is not tied to rationality. Two systems could have irrational but close initial conditions, and remain close for all times. For instance, two small dense spheres dropped from a height of approximately $\sqrt{2}$ (or any other irrational number) meters will always arrive on the ground at approximately the same time. (That’s even been tested on the Moon [this video] .) There is no chaos there, even if the initial conditions cannot be expressed using finitely many digits. This is different from other situations (the famous Lorenz system [LINK] comes to mind) where, because of non-linearity in the system, small changes in the initial conditions leads to vastly different outcomes, even if you fe