
Coin, Feather, and Gravity in a Vacuum
Hard
Do a heavy coin and a light feather really fall at the same speed? In normal air, the feather drifts slowly while the coin drops fast. But Galileo predicted that without air, both would fall together.
You place a coin and a feather inside a clear plastic tube sealed with rubber stoppers. First, flip the tube in normal air and watch the coin beat the feather. Then pump the air out with a vacuum pump and flip again.
With no air resistance, the feather falls almost as fast as the coin. Let the air back in and the difference returns immediately.
Hypothesis
The hypothesis is that a feather and a coin will fall at the same speed in a vacuum.
Method & Materials
You will need to build a vacuum tube, put a feather and a coin inside, and then pump the air out of the tube.
You will need a clear plastic tube, rubber stoppers, copper tubing, vacuum tubing, a coin, a feather, and a vacuum pump.
Results
The experiment showed that when the air was pumped out of the tube, the feather and the coin fell at the same speed. This is because the feather's lightness is balanced out by the air resistance it experiences, making it fall at the same rate as the coin.
Why do this project?
This science project is interesting because it allows you to prove a scientific theory in a fun and easy way.
Also Consider
Experiment variations to consider include using different objects of different weights, or using a longer tube to see the effect more clearly.
Full project details
Additional information and source material for this project are available below.Related video
These videos explain the science behind this project and demonstrate key concepts used in the experiment.
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