These are materials we use to make a wind-up. ( Some substitutes are shown in parentheses.)

• cardboard for wheels (paper plates, plastic lids without tabs)
• tape
• cardboard to make a spacer (bead)
• 2 rubber bands
• paper cup between wheels (cardboard roll from paper towels or toilet paper)
• stick to wind rubber band (coffee stirrer, pencil)
• 1 paper clip to pull rubber band through holes (thin wire, string)
• 1 paper clip to keep rubber band from pulling through holes (small stick)
• push pin to make holes (pencil, ball point, any pointed object)

Malik and Awad use their energy of motion, kinetic energy, to twist the rubber band. As the rubber band is twisted, their kinetic energy is being transformed and stored as elastic energy (or potential energy) in the rubber band. When the wind-up is released, the potential energy in the rubber band is converted into the kinetic energy of the moving wind-up.  Can you see where they did not put enough energy into the rubber band to make the wind-up go?