Step 1: Materials
Step 2: Make the base and arm
The hinge for the mousetrap arm is created by threading a thin skewer through three cubes with holes. A small piece of tape is wrapped on the ends of the skewer to prevent the cubes from sliding off.
Students can typically create this part of the mousetrap without any difficulty. The process is straightforward and easy to follow. Just make sure that they leave a little bit of space at the end of the arm; the cube should not be at the very tip.
Step 3: Attach the rubberband
If you've attached the rubberband correctly, the mousetrap arm should look like the last photo when being pull back. It can slam down with enough force to hurt - careful! Warn your students that at this point they should never put their hands under the spot where the mousetrap hits. I suggest marking the area with an X or other signifier.
This is where it can get tricky. Most kids do not know how to tie this kind of knot, so show them how to do it a few times. Explain it like this: put the mousetrap on the rubberband; put one side of the rubberband through the other; pull tightly.
Attaching the rubberband is not very intuitive. Emphasize that the rubberband should go under the mousetrap, then loop it onto the end of the arm.
Alternatively, the rubberband can be attached in many different ways to create different amounts of tension, which may be desirable if you're concerned about safety.