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Home · IGCSE 0625 · Space physics · How it formed · Practice
Core · Practice questions · How the Solar System formed

Cloud to planets.

Six original Cambridge-style questions on the accretion model: the nebula, gravity, the disc, accretion, and the order of events.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
What the examiner wants

Gravity pulls, dust sticks.

01
Recall
[1 mark]

State what the Solar System formed from.

  • A cloud of gas and dust (a nebula). ✓
02
Recall
[1 mark]

State the force that pulled the cloud together.

  • Gravity. ✓
03
Recall
[2 marks]

Explain what is meant by accretion in the formation of the planets.

  • Dust grains collided and stuck together. ✓
  • Over time they built up into larger bodies, the planets. ✓
04
Application
[4 marks]

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.

  • 1. A cloud of gas and dust. ✓
  • 2. A spinning disc forms. ✓
  • 3. The Sun forms at the centre. ✓
  • 4. Dust accretes into planets. ✓
05
Recall
[2 marks]

State what formed at the centre of the disc, and what happened there.

  • The Sun formed at the centre. ✓
  • It became hot enough for nuclear fusion to begin. ✓
06
Application
[2 marks]

State the force that collapsed the original cloud, and the force that keeps the planets in orbit today.

  • Gravity collapsed the cloud. ✓
  • Gravity (the Sun's gravity) keeps the planets in orbit. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.