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.

Purpose

To simulate "weightlessness" by performing a freefall demonstration

Materials and Equipment

• Styrofoam cup
• pencil or other pointed object
• water
• bucket or other object to catch the water

Method

1. Punch a small hole in the side of a styrofoam cup near its bottom.
2. Hold your thumb over the hole as you fill the cup with water. Predict what will happen to the water if you remove your thumb.
3. Place the bucket on the floor under where you are working. Remove your thumb and let the water stream out from the cup into the bucket on the floor.
4. Again, put your thumb back over the hole and refill the cup with water.
5. This time, drop the filled cup into the bucket. Try and drop the cup from the highest possible point.

Repeat the experiment several times and compare results.

Observations/Results

Record your observations in your Scientific Journal.

Questions

• How does this demonstration show microgravity for a brief moment?

Why is the water held inside the cup? What force is keeping it there?