Make a rubber-band powered wooden racer! A great, pocket-sized toy to explore transformation of energy. Bascially, a precursor to the wind-up car...

This is one of the projects for our Instructables: Made In Your Mind (IMIYM) exhibition at the Children’s Museum of Houston . Produced in partnership with Instructables, IMIYM is an exhibit where families work together to build different fun, toy-like projects that help construct knowledge and skills related to science, technology, engineering, and mathematics while instilling a “do-it-yourself” attitude in kids so they feel empowered to explore, tinker, and try to make things themselves. To learn more, check out the article here.

While this is a Children's Museum of Houston-designed activity, we found some similar activies like the Cotton Reel Tanks Instructable created by LDW. Often, the materials and process for building our projects are designed for use with a large number of visitors (we see over 800,000 annually) and the need to ensure safety in a mostly non-facilitated environment. So, yes, many of these projects have room for improvement in both materials and methodology, which is PRECISELY what we want to encourage the kids to do. So please do share your ideas for improvement and modifications!

Step 1: What You Need:

1 – Hourglass Wood Spool (1-3/8" D x 1-15/16"H) - you can get at most craft stores. We get ours in bulk from Woodworks, Ltd.
1 - 1/4" x 9/16" Metal Washer - you can get these at your local hardware store
1 – Rubber Band, #16 - available at most office supply stores
1 – Chopstick - you can get these with your next Chinese takeout. We get ours in bulk from Asian Food Grocer
1 – Standard Paper Clip - available at most office supply stores. You can also use a toothpick, but you may need to trim it down a little.
Masking Tape

We are selective in our materials for cost, ease of use, and safety due to our high traffic (800,000 visitors annually). So, for our purposes, this design worked best. But you may have other ideas - please share!

Step 2: The Video:

We offer optional video segments of each step for this project in the actual exhibit. Here is a compilation of all the steps.

Step 3: Threading the Spool

Thread the rubber band through the hole in the spool. On one end of the spool, thread the rubber band through the washer.

Step 4: Hooking Up the Rubber Band

Clip one end of the rubber band’s loop to the paper clip. Tape the paper clip to the spool centered on the spool with no parts of the paper clip sticking out. Push the thick end of the chop stick through the rubber band’s other loop.

Step 5: To Use:

To use, spin the chopstick around clockwise many times (we recommend at least 50). Place the spool onto the table with the chopstick to the right and behind it. Let go!

The Spool Car works due to transformation of energy. The twisted rubber band inside the spool stores energy because it is elastic, meaning it will return to its original shape after being stretched or twisted. As the rubber band untwists, the stored energy transforms into kinetic, or moving, energy. Because the rubber band is attached to the spool, the kinetic energy of the rubber band makes the spool spin.

By the way, if it goes "backwards," you either twisted the rubber band counterclockwise or the chopstick is on the wrong side. Just turn it around so the chopstick is on the opposite side and it will go forward.