In my AP Physics class we were required to create a mousetrap car that was able to roll 45 feet in order to obtain a 100 test grade. I was quite excited by this challenge, and created a car that rolled a total of 60 feet on the first test run, only taking a total of 3 hours to build! Here, I will be instructing you how to build a successful mousetrap car.

Although the car in the above picture uses a ruler as the frame, I later found it to be quite heavy and slowed the speed of the car. I’ll be suggesting different, lightweight material that will make car go at a somewhat faster speed.

Materials:

• Mousetrap
• 2 vinyl records
• 1 CD
• Styrofoam
• Cardboard
• A hot glue gun
• 2 lightweight rulers (ones from Home Depot or Lowes will suffice)
• 2 equal pieces of wood
• A wooden dowel
• Fishing line
• Tape
• Scissors
• Pliers

Instructions to begin building the car:

1. Taking the wooden dowel, estimate and the length needed for the back axle. For the front axle, cut it half the length of the back axle. You should have two shortened axles, one being half the size of the other.
2. Take the two rulers placing them on top of one another, and drill holes into each end of the rulers. Make sure that the holes are wide enough to hold the axles, with some space to allow rotation.
3. Obtain the CD, the styrofoam, hot glue gun, and the shorter wooden dowel. Cut out two 3×3 inch squares of styrofoam. Insert the dowel into the CD followed by the cut styrofoam on both sides. Estimate the center of the dowel and hot glue the styrofoam to the CD, then gluing the styrofoam to the dowel, securing the CD into place. Make sure that the wheels are straight, for a rickety car is not desired.
4. Cut out 8 small squares of cardboard and using a pencil, poke a hole into the middle of each cardboard piece. (The purpose of the cardboard is to keep the frame from sliding.)
5. Take two cardboard pieces and put one cardboard piece on each side of the CD.
6. Attach one record wheel similar to that of the attachment of the CD, and insert a cardboard piece to the inner side of the wheel.
7. Take the two rulers and small wooden pieces. The wooden pieces will be a base for which the mousetrap to lie upon. Insert the axles and hot glue the ends of the pieces to the rulers.
8. Glue the mousetrap to the frame, the arm facing the CD.
9. Insert cardboard pieces as noted in the example.
10. Attach the second record wheel to the other side.
11. Cut a wooden dowel to a decent size and hot glue it to the arm of the mousetrap. Remember to remove the teeth of the mousetrap (the long metal stick) for efficiency.
12. Cut out a decent-sized length of fishing line, and hot glue one end to the top of the dowel attached to the mousetrap.
13. Tape the other end to the back axle.
14. Hot glue the cardboard pieces to the axles, making sure that there is enough space between the frame and cardboard in order to reduce friction.
15. Wind the fishing line around the axle, pulling back the wooden arm.
16. Release – and there goes your very own mousetrap car!

View the mousetrap car in action here: Link  The corresponding blog may open your eyes to the possibility of using the mechanics of a spring as a basis for real-world automobile techniques, such as a torsion drive.