Hooked on Science: Jumping cup

Materials

• Two 18-ounce plastic cups

Instructions

STEP 1: Put one of the 18-ounce cups inside the other.

STEP 2: Hold the cups close to your mouth, blow softly between the rims of the cups and observe.

STEP 3: Hold the cups close to your mouth, blow harder between the rims of the cups and observe.

Explanation

Blowing air between the rims of the cups creates a force, which pushes the top cup up. Blowing softly pushes the top cup up but not out. Blowing harder pushes the top cup up and out of the bottom cup.