Video · Teachers Media
The Sun and Stars video
A lesson on our nearest star and what it tells us about the millions of others visible on a clear night. The Sun is the only star we can study up close, and everything we know about stellar physics starts here.
About this video
The KS3 curriculum introduces the Sun as a star among stars — one of hundreds of billions in the Milky Way, which is itself one of hundreds of billions of galaxies. That scale shift, from "the Sun" to "a Sun", is the pedagogical goal. Once pupils see the Sun as a member of a class, other stars become knowable.
The teaching that lands well tends to weave three strands. First, structure: the Sun as a hot ball of plasma with a core where nuclear fusion converts hydrogen to helium, releasing energy. Second, variation: stars come in a range of sizes, temperatures and colours (the H-R diagram in miniature — red dwarfs to blue giants). Third, lifecycle: the Sun will not always look as it does. A five-billion-year narrative from stellar nursery to red giant to white dwarf gives pupils a story with a beginning and end.
For pupils moving into KS4 astronomy or GCSE physics, this lesson is groundwork for spectra, nuclear fusion, and the H-R diagram. Getting the intuitions right at KS3 pays off later.
Concepts worth landing at KS3
- The Sun is a star. Other stars would look like the Sun if we were close enough to them.
- Stars vary in size, temperature and colour. Colour is a clue to temperature (blue = hotter, red = cooler).
- Stars have lifetimes — they form, shine for billions of years, and eventually die. The Sun is about halfway through.
- The Sun's energy comes from nuclear fusion in its core.
Discussion prompts
- How do you get pupils to move from "the Sun" to "a Sun", one of many?
- What would you want pupils to still know about the Sun and stars a year after your lesson?
- Where does the leap from "star" to "solar system" happen in your teaching, and how do you avoid the common confusion that our solar system is the solar system?
Try this in your classroom
- Bring up an image of a star field and ask pupils to sort the stars by colour. Then reveal what the colours tell you about temperature.
- Draw the Sun's lifecycle as a timeline on the board — five billion years back, five billion years forward. Mark where we are.
- Ask pupils to write one sentence about a distant star as if they were describing it to someone who'd never seen one.