Imagine you need to lift a heavy box onto a shelf. Would you rather lift it straight up, or roll it up a long slope? Why?

Today we build two simple machines, a lever and a ramp, and feel how they change the effort needed to move a load.

Where have you already used a slope or a stiff bar that lifts something today?

Watch this lever model. We will name the effort (your push) and the load (what moves) as we go.

In your group, build a lever from a ruler and a pivot. Rest a load near one end. Practise pressing the free end so the load rises cleanly without the ruler slipping off the pivot.

When your lever works, keep it set up for the next investigation.

Predict first, then try three pivot places: nearer the load, near the middle, and nearer your hand. Use the same load and the same hand each time.

Follow this order with the same load:

1. Build a ramp: prop a stiff board (a hardback cover, ring-binder or thick card) on classroom books or blocks up to a low raised surface.
2. Compare two ways to the same height: lift the load straight up onto that surface, then push or slide it up the ramp. Which feels easier?
3. Change only the ramp angle: try one steeper ramp and one gentler ramp to that same height. Notice how the effort changes.