Session 1 · VOICE: Investigate
Dent detectives
- 10 minDemo: press a finger gently on a balloon, then press a drawing pin with the same gentle force near it (teacher only). Why did one pop? Introduce pressure: force divided by area.
- 25 minRest the same mass (a 500 g bag of rice on a board) on blocks with different base areas sitting on plasticine. Measure each dent's depth. Then try footprints in the sandpit: flat shoes, on tiptoe, on a wide board.
- 15 minRecord the area of each base (length times width) and the dent depth. Plot area against depth.
Session 2 · VOICE: Create Conclusions
Claim, evidence, reasoning
- 15 minTool test: cut an apple with a butter knife edge and with its flat side; press a rolling pin and a skewer into playdough. Explain each with pressure.
- 10 minLook at museum photos of a toki and a ngira. What part of each concentrates the force? Why is the handle end wide?
- 25 minWrite two conclusions (car and pressure) using claim, evidence and reasoning. Swap with a partner: 'Which observation are you basing that on?'
Getting started
Use the claim–evidence–reasoning frame with one sentence for each part and a word bank (force, area, pressure, friction).
Stretch
Calculate pressure in newtons per square centimetre for your blocks (a 500 g mass pushes down with about 5 newtons).
Checkpoint
Everyone can explain, with evidence, why a sharp edge cuts and a wide base spreads a load.
Activities for this week
- Dent detectives: Does the same weight press harder on a small area?
- Tool detectives: How is a tool shaped to concentrate or spread a force?
- Sinking feet: Why do you sink in sand in some shoes but not others?
Useful this week
- Forces and Motion: Basics ↗ Push crates with and without friction and watch the force arrows.
- Forces and speed ↗ How forces speed things up and slow them down, with cycling examples.
- Simple machines ↗ How levers, wedges and wheels change the size and direction of a force.
- Pounamu adze ↗ A close look at a traditional toki and how its edge was shaped.