How Mousetrap-powered Cars Work

One of the things that makes mousetrap-powered cars so fascinating is their simplicity. Even though they work using principles of physics, you certainly don't need to be a physicist to build and enjoy them.

At their most basic, mousetrap-powered cars consist of:

In addition some builders have made cars that use the energy of multiple traps.

As you might guess, the materials used to build mousetrap-powered cars are light out of necessity. Foamcore board or balsa wood are often used for the body. The wheels can be off-the-shelf radio-controlled car wheels, but many builders use blank CDs or DVDs because their thin edges reduce friction.

So how do the cars work?

Simply put, they convert the energy of the mousetrap's spring into rotational energy that gets delivered to one set of wheels. A rod connected to the trap bar (the piece normally used to snap a mouse's neck) pulls on a long piece of string wound around one of the axles. As the string unwinds, it causes the axle and attached wheels to rotate. The spinning wheels push the mousetrap car across the floor.

Unlike when it's in mouse-catching mode, the mousetrap won't clamp on your finger and turn it into a throbbing purplish mess -- that is, if the trap is set up properly. Because it must pull against the string coiled around the wheels, the trap closes much more slowly than normal.

Got all that? If not, don't worry -- read the next page for information on how you can actually build a mousetrap-car.

You can make the building of a mousetrap-powered car a truly do-it-yourself affair by scrounging up parts from around your house and maybe the local hardware store. Or you can find a kit that has all the parts and instructions included. If you go that route, look online or try your local hobby shop. You can even build one from LEGO elements!

If you build it on your own using one of the many instructional guides available online, there's a good chance you'll need some (if not all) of the following:

One exceptionally clear set of instructions for how to turn these materials into a working car is available here. But whether you decide to build your own or do it from a kit, be sure to check that you have all the parts and tools you need, then read through all the steps before you dive in and start putting those pieces together. And remember to be smart about safety when using tools such as hot glue guns or knives with your projects.

Once your mousetrap-powered car is built, then what? Don't just let it collect dust on a shelf -- go to the next page for ideas on how to have fun with it.

If you're in school (or perhaps if you teach school), one obvious way to have fun with this is to hold a mousetrap-powered car contest. A contest is also a great way to inject some fun into groups that meet regularly, such as scouts and other clubs for youth. Who knows? You might even make it an annual event.

In addition to seeing whose car can go the farthest distance, you can award the fastest car, the most-creative design, hold multi-lane races and so on.

Once you understand the basic principles that make mousetrap-powered cars work, you can experiment with different configurations to make your car go farther or faster. You might try different sized wheels, a different number of wheels and different axle thicknesses.

You can even beef up part of the drive axle and wind the initial length of your string around it to provide a lower "gear ratio" for a more spirited launch. Wind the rest of the string around the skinny part of the axle to get your car into "high gear."

Shoot a video of your mousetrap-powered car and post it to YouTube, where there's a thriving community of Victor-powered vehicle builders. You might be inspired by other builders' designs and pick up some handy engineering tips for building your next model.

For more information about mousetrap-powered cars and other related topics, follow the links on the next page.