# 📏 Lesson Plan — Distance Lab

> **Ages 9-13 · 45 min · 1 robot per pair · ruler/tape measure**

## 🎯 Objective
Students measure obstacles in real time using ultrasonic sensing, see "sensor → number" on screen, and discover how time-of-flight becomes distance.

## 🧰 Materials
- 1 Maqueen Lite v4 robot per pair (charged)
- 1 laptop/tablet per pair (Chrome or Edge)
- 1 measuring tape or ruler per pair
- A flat wall or large book to ping at varied distances
- Optional: a cardboard "obstacle alley" to drive through

## 📋 Lesson flow (45 min)

| Time | Phase | Teacher | Students |
|---|---|---|---|
| 0-5 | **Hook** | Bat clip or sonar ping audio. "How does a bat 'see' in the dark?" | Discuss: sound out, sound back, time = distance. |
| 5-10 | **Demo** | Open Distance Lab. Hand in front of sensor → live number jumps. Show **radar** + **parking** modes. | Watch the number react. Predict at what distance the alarm fires. |
| 10-25 | **Exploration** | Pairs connect, point robot at a wall, write down: 10 cm = ?, 30 cm = ?, 1 m = ?. | Measure with the tape; cross-check with the lab number. |
| 25-40 | **Challenge** | "Park your robot 5 cm from the wall using only the parking helper, no eyes on the robot." | Slow approach; refine; aim for ±1 cm precision. |
| 40-45 | **Reflection** | "When does the sensor lie?" Hands-up. | Identify edge cases (angle, soft surfaces, distance > 4 m). |

## ✅ Success criteria
- I can read the live distance value and convert it to cm.
- I can predict whether the alarm will fire at a given distance.
- I can park my robot within ±1 cm of a chosen target.

## 📚 Standards
- **FR Cycle 3** — *Sciences* : propagation du son ; mesure et grandeurs.
- **FR Cycle 4** — *Phys-Chim* : ondes mécaniques (vitesse du son). *Tech* : capteur, signal, traitement.
- **NGSS** — 4-PS4-1 (waves); MS-PS4-1 (model wave properties).
- **CCSS-M** — 4.MD.A.1 (measurement units).
- **CSTA** — 1B-DA-06 (collect/store data with sensors).

## 🚀 Extension
- Use the **Theremin** mode: convert distance → musical pitch. Bridges to the Music Lab.
- Calculate the speed of sound: known distance ÷ measured echo time.
- Plot distance vs. time during a slow approach (graph paper).