Graph the motion of feather dropping vertically through air, in terms of speed and time.
Here are speed–time (v–t) graphs:
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Feather (first chart): Speed starts at 0 and slowly rises toward a small terminal speed (horizontal dashed line). Air resistance quickly balances gravity, so the feather never gets very fast.
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Feather vs. Stone (second chart):
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Feather: approaches a low terminal speed slowly.
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Stone: accelerates rapidly and reaches a much higher terminal speed; after that its speed stays nearly constant.
Hammer and Feather Drop on the Moon (Apollo 15, 1971)
In 1971, astronaut David Scott did a famous experiment on the Moon. He dropped a hammer and a feather at the same time. On Earth, the feather would fall slowly because of air. But on the Moon, there is no air — so both objects fell together and hit the ground at the same time!
What Happens When Things Fall?
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On the Moon, gravity pulls objects down with a force of about 1.62 m/s².
(That means every second, the object’s speed increases by 1.62 meters per second.) -
If you drop something from 1.5 meters high:
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It takes about 1.36 seconds to hit the ground.
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The speed when it hits is about 2.2 m/s (about the speed of a fast walk).
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Graphs
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Acceleration vs Time
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A flat line.
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The hammer and feather fall with the same constant acceleration: 1.62 m/s².
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Velocity vs Time
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A straight line going up.
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Their speed increases the longer they fall.
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Displacement vs Time
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A curved line (parabola).
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They move farther and farther down each second.
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The Big Idea 🌙
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On Earth: the feather falls slower because of air resistance.
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On the Moon: no air resistance → hammer and feather fall together.
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This proves that gravity pulls on all objects equally, no matter how heavy they are.
👉 Do you want me to redraw the graphs in a super simple “cartoon-like” way (with hammer and feather symbols) so it looks perfect for grade 6 science?
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