Preview · the opening missionRead this to the class:
One evening in Mexico City, Diego watched the International Space Station slide across the sky like a bright, silent star. His little sister asked two questions he couldn't answer. "If gravity pulls everything down, why doesn't the space station fall? And why doesn't the Earth fall into the Sun?" Your team's job: build an orbit with your bodies, then use real data to explain what keeps a planet going round.
Teams of three, with three jobs that rotate: Sun (stands still and turns on the spot), Planet (walks the orbit), Observer (watches and records).
Look inside the PDF
Sample pages, stamped “preview”. The download is the clean, full lesson.
In the full lesson PDF
10 printable pages
- Predict (5–10 min)
- Hunt (20 min)
- Reveal (10–15 min)
- Act (10 min)
- Background for the teacher
- Assessment
- Student sheet
- Worksheet: Orbit data card
- Worksheet: Label it
- Worksheet: Try it at home
On the student sheet
- My prediction
- What we saw in the human orbit
- Graph: year against distance
- Diego's answer
- Exit ticket
- Orbit data card
- Label it
- Try it at home
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 for all 3 lessons in this unit.
What students show by the end
- Uses the model
- Predicts motion without gravity
- Reads the data
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 planets go around the Sun and not fly away?” take?
50–60 min. Group size: pairs for the human orbit, teams of 3 for the graph.
How much prep does it need?
5 minutes: print the Student sheet for everyone and the Orbit data card, one per team. Clear a space about 4 m (13 ft) across in the room, the hall or outside.
What materials do I need?
None. No materials needed: just the printed sheets.
Which curriculum standards does it cover?
NGSS (US): MS-ESS1-2 (partly). It also matches England National Curriculum, Year 5; England National Curriculum, Key Stage 3 and Cambridge Primary and Lower Secondary Science (not endorsed by Cambridge).
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”, “What we saw in the human orbit”, “Graph: year against distance”, “Diego's answer”, “Exit ticket”, “Orbit data card”, “Label it” and “Try it at home”) 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 for all 3 lessons, yours to keep, or every lesson is US$199 a year.