There are also moons in the solar system, that is objects orbiting around the planets. In fact just over 180 moons at the last count.
And some of those moons are so large that if they were orbiting around the sun, rather than the planets, they would count as planets in their own right.
So for example, Saturn's largest moon, Titan, a fascinating world, has a diameter larger than the planet Mercury, but it doesn't count as a planet because it's orbiting around Saturn and not around the sun.
This short video gives an interesting insight into moons in the solar system.
By giving a current estimate of the number of moons in the solar system, its magnitude is highlighted.
The point is made that the study of space is a developing science, with new discoveries about the solar system being made over time and as technology develops.
The video also explains the difference between a moon and a planet, using Titan, the largest moon of Saturn, to exemplify.
Teacher notes
Points for discussion
Students sometimes think there is only one moon in the solar system, the one orbiting Earth. This video helps to give students a bigger picture of the solar system and to appreciate its magnitude.
The video also supports students to understand the relationships between the different components of the solar system.
Suggested activities
After watching the film, KS3 students could learn (or research) information about other planets in the solar system and the moons that orbit them. They could also move on to learn about other galaxies.
Students could be asked to suggest why the total number of moons in the solar system is an estimate and why it has increased over time. Students could then learn about how the technology used to make these discoveries has developed over time.
After watching the film, students could apply their knowledge and understanding of gravitational fields to explain trends in the number of moons for planets of different mass.
At KS4, this video could be used for revision of the features of the solar system before progressing on to comparing planets, their moons and artificial satellites.
Curriculum information
Suitable for KS3 England, Wales and NI and CfE Scotland, S1-3, Combined Science and Physics GCSE in England, Wales and Northern Ireland and at National 4 and 5 in Scotland, and Cambridge IGCSE Physics.
Why do we have days, nights and seasons? video
A demonstration, using everyday objects, of how the Earth moves to give us days and nights, and seasons.
Why do astronomers use 'light years' to measure distance in space? video
A short explanation of ‘light years’ and why scientists use them in place of standard units of measurement when talking about space.
What is the Milky Way? video
A description of the Milky Way and its components, including stars, dust, gas and the mysterious ‘dark matter’.
The solar system. video
A description of the solar system including the eight planets, the asteroid belt, dwarf planets, the Kuiper Belt and the Oort Cloud.
