Preview · the opening missionRead this to the class:
The school bus is rolling down the street. The driver spots a cat and brakes hard. Nobody pushed the students, but every one of them tips forward, and a backpack slides off a seat and hits the floor. Your team's job: find out what threw everyone forward, and design something to keep a passenger safe.
Teams of three, with rotating jobs: Driver (releases the car), Measurer (measures where the passenger lands), Recorder (writes data and draws).
Look inside the PDF
Sample pages, stamped “preview”. The download is the clean, full lesson.
In the full lesson PDF
- Predict (5–10 min)
- Hunt (20 min)
- Reveal (10–15 min)
- Act (10 min)
- Background for the teacher
- Assessment
- Student sheet
On the student sheet
- My prediction
- Our results
- Our graph
- Seatbelt test
- CER for the bus company
- Exit ticket
US Letter, prints cleanly in black and white. The student sheet is on its own page, ready to photocopy.
Free with an account (any 3 lessons), or US$19 / C$25 for all 4 lessons in this unit.
What students show by the end
- Collects and graphs data
- Explains inertia
- Uses evidence in a CER
From the lesson’s rubric, which scores each one as not yet, getting there or got it.
Questions teachers ask
How long does “Why do you lurch forward when a bus stops?” take?
50–60 min. Group size: teams of 3.
How much prep does it need?
15 minutes: set up one ramp per team (a board or stiff cardboard about 1 m (3 ft) long, propped on books). Tape a low barrier to the floor about 30 cm (12 in) past the bottom of each ramp: it must be lower than the car's roof, so the passenger can fly over it. Roll each modelling clay ball to about the size of a large marble.
What materials do I need?
Index card or playing card; plastic cup or glass; coin (any, a heavier one works best); toy car or truck with a flat roof or flat bed (dollar-store pickups work well); modelling clay (non-hardening); board or stiff cardboard, about 1 m (3 ft) long, for a ramp; and 4 more. Cost: about $20 for a class of 30.
Which curriculum standards does it cover?
NGSS (US): MS-PS2-2.
What’s in the lesson PDF?
A teacher guide that walks you through predict, hunt, reveal, act, background for the teacher and assessment, then a student sheet (“My prediction”, “Our results”, “Our graph”, “Seatbelt test”, “CER for the bus company” and “Exit ticket”) on its own page, ready to photocopy. It’s US Letter and prints cleanly in black and white.
Can I try it for free?
Yes. A free account includes any 3 full lessons of your choice, and this can be one of them. After that, this unit is US$19 (C$25) for all 4 lessons, yours to keep, or every lesson is US$79 (C$109) a year.