To make a mousetrap car move, string must be attached from the lever arm to the axle and wound around it. Then when the mousetrap car is released, the string is pulled from the drive axle, causing it to move forward. You need a mousetrap car base, a mousetrap, string, a long lever arm and an axle hook.
- Tie a string to the mousetrap's lever arm
Remember that the string needs to be quite long because it propels the mousetrap forward. Tie the string to the tip of the lever arm. It is recommended to use Kevlar fishing line as the string.
- Attach an axle hook to the drive axle
The axle hook is where the other end of the string is attached. Attach an axle hook, and glue it in place so that it doesn't move around.
- Tie a loop knot in the free end of the string
Tie a loop knot by folding the string and tying a traditional knot with the folded part. Then pull the loop tight.
- Hook the loop knot on the axle hook
- Wind the string around the drive axle
Wind the string around the drive axle by turning the wheels in the opposite direction of the mousetrap car's intended motion.
- Release the mousetrap car
Once the string is fully wound, the mousetrap car can be released. It pulls the string from the drive axle, which propels the car forward.