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The Solar System: planets, asteroids and comets video
A KS3 introduction to the objects that share our solar system: eight planets, the dwarf planets beyond, the asteroid belt, and the comets that swing in from the outer dark. It works well as the opening lesson of a unit on Earth in space, giving pupils the mental map they'll fill in over the following weeks.
About this video
Solar system teaching in the KS3 national curriculum sits alongside "gravity forces between the Earth, Moon and Sun" and the seasons. The topic's pedagogical challenge is scale — the numbers are so large that pupils lose their meaning. A billion kilometres and a million kilometres feel the same until you make the difference physical.
The best introductions use scale as their core teaching device. If the Sun is a football, Earth is a peppercorn 25 metres away and Neptune is a marble 800 metres beyond. Playground-scale models like this reliably shift pupils' intuitions in a way that a diagram in a textbook does not. Pair the physical model with a proper account of what distinguishes a planet (Pluto's reclassification in 2006 is a great lesson in how science definitions work) and you have a lesson pupils remember.
For stretch, pupils can work on the physics behind orbit — why does Neptune take 165 years to go round the Sun and Mercury 88 days? — which sets up gravitational force as the causal mechanism, ready for KS4.
Curriculum links (KS3)
- Gravity forces between the Earth, Moon and Sun (revisiting the inverse-square relationship at KS4)
- The seasons — axial tilt versus orbital distance
- The relative motion of the Sun and Earth
- Our Sun as a star, other stars in our galaxy, other galaxies
Discussion prompts
- How do you make astronomical scale felt rather than just stated?
- What misconceptions do pupils typically arrive with about the solar system, and where do those misconceptions come from?
- How does your solar system lesson connect forward to gravity, orbits and cosmology at KS4?
Try this in your classroom
- Run the classic playground scale-model: Sun a football, planets on scaled fruit. Pupils walk out the distances themselves.
- Use the Pluto reclassification as a case study in how science definitions change. What did the IAU decide in 2006, and why?
- Assign pupils one solar-system object to research and present in 90 seconds. The class ends the lesson with a mini atlas of the solar system.