Cause & effect1½–3½ yrsOutdoors

Ball ramp

A plank, a slope, and the same delight thirty times over.

Prep

2 min

Mess

Low

How to play

Prop up one end and let the ball go. He chases it, brings it back, does it again. Then try: what if we lift it higher? What if we use a bigger ball?

  1. a flat plank on the ground beside a ball
    1

    A ball, and a plank to make a slope.

  2. the ball rolling down the propped plank
    2

    Prop one end up and let the ball go.

  3. a steeper ramp with a bigger ball and an arrow showing the lift
    3

    Then lift it higher. Then try a bigger ball.

What you need

A ball and something to make a slope — a plank, a big piece of cardboard, or just a hill.

What it secretly builds

Cause & effect

Steeper means faster. He's discovering a rule about the world by changing one thing and watching what happens — which is exactly what an experiment is.

Spin again