Too Short?

Purpose: To simulate the affect of gravity on height

Materials

• large-mouthed jar
• science journal
• scissors
• small baby food jar
• 2 balloons (9 in.)

Procedure

1. Using the scissors, cut the neck from one of the balloons.
2. Stretch the balloon over the mouth of the baby food jar, completely covering the opening. See diagram 1.
3. Place the covered baby food jar inside the larger jar.
4. Cut the tip off the rounded end of the second balloon. See diagram 2.
5. Stretch the balloon over the mouth of the large jar so that the neck of the balloon is centered over the jar’s mouth.
6. Push the surface of the stretched balloon down into the jar, letting the air inside the jar escape through the open neck of the balloon. See diagram 3.
7. Twist the balloon’s neck and pull it upward. See diagram 4.
8. Observe the stretched balloon over the baby food jar.
9. Record your observations. What you observed is similar to what would happen to the spinal cord in a low gravity environment, but the balloon on the baby food jar is still in a regular gravity environment. This kind of experiment is called a simulation.
10. Push the balloon down again and observe. This experiment represents a high-gravity environment. Record your observations.

Conclusion

1. What happened to the balloon on the baby food jar when you pulled the neck of the balloon on the large jar upward?
2. What happened when you pushed it back down?
3. The human body has a spinal cord that is made of many separated discs. What do you think happens to the spinal cord in a low gravity environment?
4. How might a low gravity environment affect a person’s height?