What controls a catapult’s range?

Catapult: test pullback and angle separately

Pulling back the arm stores energy in the stretched mechanism. On release, the arm moves and gives the ball its initial motion. The launch angle divides that motion between upward and forward travel. A higher arc therefore need not be the longest throw.

Start by increasing pullback slightly while keeping the ball, target and angle the same. Mark the two landing spots. Then change only the angle. Your child can see whether the ball rises higher, travels farther or misses the target without mixing two causes.

Try it together in the lab

1. Begin with a prediction. You do not have to agree.
2. Change Pullback from 18 cm to 21 cm; keep the ball and angle unchanged.
3. Follow the arm and release together, then compare the landing positions.

Next comparison: Change only the launch angle slightly, keeping the pullback, ball and target unchanged.

An activity away from the screen

Away from the screen, use a soft paper ball and a short, adult-supervised launch toward an empty cardboard box. Choose a clear space, never aim at people or animals, and avoid hard projectiles.