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Recommended for grades 8-9
Everywhere in our universe, we feel the pull of gravity. When astronauts go into space, they experience "weightlessness" and everything falls freely at the same rate. People appear to have no weight because there is nothing in the way to stop their fall.
The zero-gravity that astronauts experience inside the Space Shuttle is not really zero-gravity at all. Zero-gravity implies that the gravitational pull in space is zero. This is not the case.
Astronauts "float" in space because they are in a state of free fall produced by their orbital motions around Earth. Astronauts and their spacecraft are falling together. This condition is sometimes called "weightlessness" because a bathroom scale inside the Shuttle would not record any weight for an astronaut standing on it. The scale would be falling as well. The more accurate term is microgravity, since astronauts and the spacecraft do make a small gravitational attraction for each other.
To simulate "weightlessness" by performing a freefall demonstration
Repeat the experiment several times and compare results.
Record your observations in your Scientific Journal.
Why is the water held inside the cup? What force is keeping it there?