This aluminum can racer is powered by a rubber band and can travel about 20 feet at speed. Just wind it up and let it go. It also demonstrates the conversion of potential energy (when the rubber band has been turned a few times) into kinetic energy (when its let go).

Supplies

Aluminum beverage can
1 or 2 large rubber bands
8 inch long stick or tube.
Sandpaper for grip

Tools:
Nail and hammer or drill
Thin stick
Glue

Step 1: Make a Hole in the Base of the Can

Make a hole in the base of the can for the rubber band to come out. I used a hammer and nail but a drill could also be used.

Step 2: Thread Through the Rubber Band

Using a thin stick, thread one end of the rubber band through the opening at the top of the can and out through the hole at the bottom.
I needed to join 2 bands together to give move length.
Attach one end of the band around the can's opening tab and the other end around a stick or tube. The tube I used was about 8 inches long and made from a piece of rolled up aluminum, but a piece of dowel or stick would also work.

Step 3: Wind It Up and Let It Go

Wind up the rubber band by holding the can and turning the stick.
When I let it go the first time the can spun around itself and didn't go straight. This was because the can didn't have enough friction to the floor. I fixed this by gluing on a strip of sandpaper to increase its friction.