Introduction: Spool Car
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
Step 2: The Video:
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.

Participated in the
Pocket Sized Contest
8 Comments
6 years ago
I just came a cross of this! It brought me back in time. This was my favor and only you that I had. I grow up on the farm, back in Brazil, and we lived a very modest life. I missed it very much, we were free and so happy then. It was no electric power, no automobiles, tractors was the horse's and donkeys. I want to make one so my kids can see it, but I can't fine wood spools, we called it "Carretel" Overthere. It's great see it done here, we have to keep history a life, speacilly now that lots of people want to kill it.
8 years ago on Introduction
My father make me one around 50 year too , I could not give to my children already today 28 years old because in the era of plastic is difficult to find a wood
10 years ago on Introduction
My father taught me to make these over 50 years ago (he made them as a child being a farm boy in Canada about 1920).
One of the best modifications is to cut tracks (V shape) in the spool every 1/4 inch. these could climb there way out hole dug in the ground, tossing dirt as it went. Elastic choice is important try a wider thicker band (experiment). Instead of tape, and paper clip we used a pin or small nail and cut a slot into the spool so it would not slip.
Given washers cost money. I would opt to take my mom’s sock darning wax and slick up the side it worked just fine.
We also added a second drive spool, wind them correctly so they go in the same direction, at that point you can add a paper car body taped to the chopstick.
I wasted many an hour modifying them and racing them up hill.
It is a lost art, given thread does not come on wooden spools, you have to go out and “buy” them. Mine came from my mothers sewing to keep 4 kids hand me downs going and the rod was from my Tinker Toy set.
Reply 9 years ago on Introduction
Wonderful ideas!
9 years ago on Introduction
I heard about this project at a children's workshop at the National Waterfront Museum in Swansea, UK. The staff at the museum gave me the link to Instructables and I have now ordered the materials and I am going to try it for Open Evening at my school. I will let you know how it goes.
10 years ago on Introduction
I did this but with a pencil from the "art man" on pbs teaching me.
10 years ago on Introduction
Feeling nostalgic, and a wee bit ancient! Nicely demonstrated...........
10 years ago on Introduction
Good idea!