Preview · the opening missionRead this to the class:
A crossing guard notices something. When a small car stops at her sign, it stops quickly. When a loaded delivery truck comes down the same hill at the same speed, it needs much more room to stop. She wants to tell drivers why. Your team's job: find out how an object's mass changes how hard it hits, and give her the evidence.
Teams of three, with rotating jobs: Loader (adds coins and releases the car), Measurer (measures the cup), Recorder (writes and graphs).
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
- What I noticed about speed
- CER for the crossing guard
- 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
- Runs a fair test
- Graphs and reads data
- Explains with momentum
From the lesson’s rubric, which scores each one as not yet, getting there or got it.
Questions teachers ask
How long does “Why does a heavier cart hit harder?” take?
50–60 min. Group size: teams of 3.
How much prep does it need?
15 minutes: set up one ramp per team at 15 cm (6 in) high on a smooth floor or long table. Mark a cup line with tape right at the bottom of each ramp. Collect identical coins or metal washers, 12 per team. If you have a kitchen scale, weigh one car and one coin so teams can work in grams.
What materials do I need?
Toy car with a flat roof or bed (the same cars from Lesson 1); identical coins or metal washers; paper cups, about 250 mL (9 oz); ramp board and books; masking tape; metre stick or measuring tape; and 2 more. Cost: about $10 for a class of 30, if you have the toy cars and ramps from Lesson 1.
Which curriculum standards does it cover?
NGSS (US): MS-PS2-1, MS-PS2-2 and MS-PS3-1 (partly).
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”, “What I noticed about speed”, “CER for the crossing guard” 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.