Hooked on Science: Smoke-ring launcher

Materials

• 32-gallon trash can
• Shower curtain
• Two bungee cords
• Fog machine

Instructions

• Step 1: Using a knife, have an adult cut a 5-inch hole in the bottom of the trash can.
• Step 2: Cut a large square from the shower curtain. Make sure the square is large enough to stretch over the top of the trash can.
• Step 3: Stretch the piece of shower curtain over the top of the trash can.
• Step 4: Secure the piece of shower curtain with the bungee cords.
• Step 5: Have a friend point the launcher toward your face and gently hit the shower curtain with the palm of his or her hand. Describe the air by using its observable properties. Describe how the launcher can be used as a model to describe how matter is made of particles too small to be seen.
• Step 6: Using the fog machine, fill the trash can with smoke, gently hit the shower curtain with the palm of your hand, and observe. Describe what you see by using its observable properties.

Explanation

The air cannon proves air takes up space and shows how a vortex is formed. The shower curtain makes the shape of a cone as it's pushed inward with the palm of your hand. The air pressure on the inside of the trash can increases, and the air is forced into a rotating ring as it moves through the opening.