---
title: "Lift"
subtitle: "Capstone projects · Years 9–10: move it · Lesson 6"
---

# Lift

**Name:** {{field-24}} **Date:** {{field-15}} **Class:** {{field-15}}

> **Key question:** The winch lesson worked on paper. Does a real motor, real gears and real friction agree with the numbers?


:::teacher-note

**In one sentence:** A Years 9–10 design project: a motor-driven lift where the gear ratio is chosen against the brief on the gears board, driven both ways through a motor driver, and the measured lift time compared with the model's prediction.

**Students should be able to say:** I can choose a gear ratio against a brief. I can drive a motor both ways through a driver. I can compare a model's prediction with a measurement and explain the gap.

**Width:** the unmarked parts are the floor every student does (predict, run, investigate and make). Typical adds the modify practice; wider adds the real-world contexts. They add contexts, not difficulty. Students work in the online tutorial alongside this sheet.

:::


## Inquire: the brief


:::keep-together

**Sort each line of the brief: a criterion (what it must do, which you can test) or a constraint (a limit you must work within)?**

Groups: Criterion, Constraint

- Lifts 450 g by 1 m: {{field-15}}
- Takes 15 s or less: {{field-15}}
- Stops at the top and can lower again: {{field-15}}
- Motor 120 rpm, 200 g with no gears: {{field-15}}
- Gears from the kit: 8, 16, 24, 40: {{field-15}}
- A motor driver and its own battery: {{field-15}}

:::


:::teacher-note

**Answer:** Lifts 450 g by 1 m → Criterion; Takes 15 s or less → Criterion; Stops at the top and can lower again → Criterion; Motor 120 rpm, 200 g with no gears → Constraint; Gears from the kit: 8, 16, 24, 40 → Constraint; A motor driver and its own battery → Constraint

Criteria are what you will test at the end; constraints decide what you are allowed to build with.

:::


## Develop: plan before you build


:::keep-together

### Margin

**Real gears lose about 10% of the force at each mesh. Which pair has more margin on strength?**

☐ 16 → 40: 500 g against 450 g

☐ 8 → 24: 600 g against 450 g

☐ They are the same

☐ Neither: friction doesn't matter

:::


:::teacher-note

**Answer:** 8 → 24: 600 g against 450 g

600 × 0.9 = 540 g, still over 450. 16 → 40 drops to exactly 450 with no margin.

:::


## Create: build it


**In the simulator.** 

**For real.** 

Work in the tutorial. Plan first: what will you change, and how will you test it?

{{box-4}}


:::wider

## Test: run your table


**Run the tests.** 

**Fix and re-test.** 

Work in the tutorial. Plan first: what will you change, and how will you test it?

{{box-4}}

:::


## Evaluate: against the brief


:::keep-together

### Which is evidence?

**Your lift takes 17 s; the model predicted 15 s. What is the best explanation to give in your evaluation?**

☐ The gears are broken

☐ The brief was unfair

☐ The stopwatch was wrong

☐ The model ignores friction and the motor slowing under load; measure and say how much

:::


:::teacher-note

**Answer:** The model ignores friction and the motor slowing under load; measure and say how much

Real motors slow under load, and every mesh loses a little: the model's 15 s is a best case.

:::


## Exit ticket

:::keep-together

**Why might a real lift be slower than the gear model predicts?**

{{lines-3}}

:::


:::teacher-note

**Answer:** The model ignores friction at each gear mesh and the motor slowing under load.

:::