Nothing helps students understand Newton's Laws and forces better than feeling them! These are instructions for building a pair of floor carts so the students can predict and then test different scenarios involving Newton's Laws. I recommend students wear their bike helmets when using these if they are going to get up to any speed.
Materials for one cart:
8 steel elbows
1 - 3 ft x 3 ft piece of plywood
2 - 3 ft length of 2 x 4
1 pair of the cheapest roller blade style skates you can find (try the clearance isle at your local sporting good store)
16 bolts/nut sets
soft rope for handles
screwdriver or drill with screwdriver bit
allen wrench to fit the roller blade wheels (frequently is included in the packaging for the skates)
Step 1: Assembling the Base Structure
Securely screw the two lengths of 2 x 4 to the plywood. The purpose of these boards is to reinforce the plywood where the wheels will be attached.
Use screws that will be flat with the surface so students will not nick themselves on screw heads while riding the cart.