A Real Gem

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Vehicles that skim over rough seas and rugged terrain on a cushion of air are called hovercraft, hydroskimmers or ground-effects machines (GEM). You can build a model that will show how these almost friction-free air supported vehicles work.

Materials:

• A metal pie pan with a smooth bottom
• A spool
• Glue
• A balloon

1. Turn the pan over and punch a small hole in the center.
2. Glue the spool to the inside of the pan, centering it over the hole.
3. Stretch the neck of the balloon well down over the spool.
4. Inflate the balloon by blowing through the hole in the bottom of the pan.