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Year 4 Science

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A solar system model

You can make a model of the solar system. It will give you an idea of just how spread out it all is. Our scale will be tiny. We'll make our planets bigger, so you can see and touch them, but really we are thinking about the distances of planets from the Sun.

You need nine beads, some pipe cleaners, some polyester sewing thread (or string) and some scissors to cut them. Stand a stick or a pole up in the ground. A cricket stump is ideal. It stands for the sun so the planets can orbit it.

solar system

Inner planets

You know that four planets are much nearer the Sun than the others. We will model them with pipe cleaners. You have four inner planets, so you need four pipe cleaners and four beads.

The distances from the centre are:
Mercury 4 cm, Venus 7 cm, Earth 10 cm, Mars 15 cm

Curl one end of a pipe cleaner around the stump or pole, then, with a ruler, measure a straight section the right distance from the pole. Bend the other end upwards, through the middle of a bead and bend the tip over to stop the bead falling off. You may have to join two pipe cleaners together for Mars, if one is too short.

Outer planets

The five planets of the outer solar system need to be a lot further away. We'll now use the sewing thread for the five outer planets. Tie a bead to the end, measure the correct distance, allowing some extra for tying up, then tie the other end around the central pole. You probably need to be outside for this part. The distances are:

Jupiter 50 cm, Saturn 1 m, Uranus 1.9 m, Neptune 3 m, Pluto 3.9 m

Orbits

Now do you see how big the solar system really is? The Sun is a long way from the Earth. It is so far away that, although it is far bigger than the Earth, the Sun looks small in the sky. And yet the distance to Neptune is many times further again.

When you have made the model, try making some planets start to orbit. Hold the bead that represents your chosen planet and move anti-clockwise around the pole for the Sun. Try to keep the pipe cleaner or the thread straight and watch out for tangles. Think about how to keep the other threads out of the way while a planet is orbiting. The orbit is just like a thread keeping our planets the right distances from the Sun. Earth's orbit is bigger than Venus's orbit, Jupiter's orbit is even bigger and Pluto's orbit is even bigger than that. This gives us an idea of how big the solar system is.


This activity is adapted from pages 349-350 of What Your Year 4 Child Needs to Know, which can be purchased here. Click below to see the related activities.

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