Session 1 · DESIGN: Sketch
Pulleys, gears and cranks
- 10 minDemo: lift a 1 kg bag with a spring balance. Now lift it with one fixed pulley, then with two pulleys. Predict before each test.
- 25 minStations: cotton-reel pulleys, cardboard gears, a pencil-and-reel crank winch. Record input turns and output movement at each.
- 15 minAdd the mechanism to your design sketch: where will the pulley, crank or tie go? Draw a scaled 3D view.
Session 2 · DESIGN: Improve
First build
- 5 minSafety briefing: goggles, glue station, loads under 1 kg, heads clear.
- 40 minBuild the first working model. Photograph each step for your report.
- 5 minQuick test with no load. Does it stand? Does it move?
Getting started
Start with one fixed pulley only; add a crank later.
Stretch
Build a pulley system that lifts 1 kg with half the effort, and measure it with the spring balance.
Checkpoint
A first model that stands up and has a working mechanism or brace.
Activities for this week
- Pulley power: How do pulleys make lifting easier, and what do you pay for that?
- Gear trains and a crank winch: How can turning a handle pull a flying fox seat home?
Useful this week
- Triangles and trusses ↗ Diagrams showing why trusses use triangles and how forces travel.
- Tinkercad ↗ Free 3D modelling to draw your tower or bridge before building.
- Simple machines ↗ How levers, pulleys and gears trade force for distance.
- EPro8 Challenge ↗ New Zealand engineering challenges, including the flying fox and helicopter rescue.