Create your own smoke-ring launcher with a few materials from around the house.

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 this 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: Using the fog machine, fill the trash can with fog, gently hit the shower curtain with the palm of your hand, and observe

Explanation

The air cannon proves that air takes up space and shows how a vortex is formed. The shower curtain makes the shape of a cone as it moves inward. The air pressure on the inside of the can increases and the air is forced into a rotating rind as it moves through the opening.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website www.hookedonscience.org for webcasts and experiments.