The shape of the lesson
By the end of the lesson, learners can
- Collapse the cloud: Let gravity pull the cloud together and watch the Sun and planets take shape.
- Sun first, then planets: Gravity makes the Sun from most of the mass, and accretion builds the planets from the rest.
- Start: a cloud of gas and dust (nebula).
- Drive: gravity pulls it together.
- Build: dust accretes into planets.
One picture every idea returns to
The Solar System formed from a cloud of gas and dust that collapsed under gravity. Most of the mass gathered into the Sun at the centre, while the remaining material in a spinning disc clumped together by accretion to build the planets.
Forty-five minutes, phase by phase
| Time | Phase | What happens in the room | Grouping |
|---|---|---|---|
| 0 to 5 min | Hook: predict | Open with the question in the title, Built from a cloud.. Long before the planets, there was only a vast, cold cloud of gas and dust. | Whole class, then pairs |
| 5 to 17 min | Teach and check: Collapse the cloud | Let gravity pull the cloud together and watch the Sun and planets take shape. Project tab 3 of the lab (Formation) and let a student drive it while the class predicts. | Whole class, then pairs |
| 17 to 30 min | Teach and check: Sun first, then planets | Gravity makes the Sun from most of the mass, and accretion builds the planets from the rest. | Cooperative Concept Mapping |
| 30 to 36 min | Check | The four Stage 1 questions from the student lesson, answered on mini whiteboards or by show of fingers. Re-teach the one most get wrong. | Individual, then whole class |
| 36 to 43 min | Plenary | The exam-style questions from Stage 2, one at a time: thirty seconds alone, then a random call. The feedback lines in the key give the examiner's wording. | Individual, random call |
| 43 to 45 min | Exit and homework | Set the worksheet below (6 questions, 12 marks). Learners self-assess against the objectives before they leave. | Individual |
Protect the parts that carry the learning
The sequence carries about fifty minutes of material, so the lab is driven by one student while the class predicts rather than explored freely. Times are a guide.
Protected: the check at 30 minutes. It is the only individual read on whether the key idea landed, and it is not cut.
Cut first if the build overruns: the last check in Sun first, then planets, never the check or the plenary.
In a 60 minute block: run worksheet questions 1 to 3 in class as a Rally Coach set and model both the hardest worked example and its check live.
Cooperative Concept Mapping
Teams receive the key terms on cards and arrange them on a large sheet, drawing and labelling the links. Compare maps between teams before showing the model map.
The full structure, with its variations and the other twelve, is on the cooperative-learning page.
What to head off, and how
| Trap learners fall into | Teaching move that pre-empts it |
|---|---|
| It was gravity that pulled the cloud of gas and dust together, and the planets grew by accretion, smaller clumps sticking together into larger bodies, in the disc around the young Sun. | Return to Sun first, then planets: ask a pair to state the correct version and show it on the lab before moving on. |
Formation of the Solar System: worksheet
6 questions, 12 marks. Written in the style of the papers; no past paper question is reproduced.
State what the Solar System formed from.
State the force that pulled the cloud together.
Explain what is meant by accretion in the formation of the planets.
Put these stages in the correct order: the Sun forms at the centre; a spinning disc forms; a cloud of gas and dust; dust accretes into planets.
State what formed at the centre of the disc, and what happened there.
State the force that collapsed the original cloud, and the force that keeps the planets in orbit today.
Answer key and marking notes
A cloud of gas and dust (a nebula). ✓
Gravity. ✓
- Dust grains collided and stuck together. ✓
- Over time they built up into larger bodies, the planets. ✓
- 1. A cloud of gas and dust. ✓
- 2. A spinning disc forms. ✓
- 3. The Sun forms at the centre. ✓
- 4. Dust accretes into planets. ✓
- The Sun formed at the centre. ✓
- It became hot enough for nuclear fusion to begin. ✓
- Gravity collapsed the cloud. ✓
- Gravity (the Sun's gravity) keeps the planets in orbit. ✓
2 multiple-choice questions on this lesson
From the topic question bank. Assign them in the app for a marked score in your gradebook, or run the topic as a class game.
According to the accretion model, how did the Solar System form?
- AA cloud of gas and dust was pulled together by gravity, forming the Sun and planets.
- BThe planets were thrown off from the spinning Sun.
- CTwo stars collided and the pieces became planets.
- DThe Solar System has always existed unchanged.
In the collapsing cloud that formed the Solar System, what formed at the very centre?
- Athe Sun, where most of the mass gathered
- Bthe largest planet, Jupiter
- Cthe asteroid belt
- Dthe Moon
Quiz key
The Solar System formed when a large cloud of gas and dust (a nebula) was pulled together by gravity; the Sun formed at the centre and the planets formed from the surrounding spinning disc. It did not break off the Sun or come from a collision.
Most of the mass fell to the centre, becoming dense and hot enough to form the Sun; the planets formed later from the leftover material in the disc around it. Jupiter and the asteroids formed further out.
What to project
The student lesson embeds these tabs. Open them full screen on the projector; every slider has a drag handle on the stage.
Slides for this lesson
A projectable deck for every pack is on the way. Until then, present the student lesson full screen: its sections, figure and lab tabs follow the same order as the plan above.