Year 5 science · Key Stage 2 · Earth and space

Year 5 space: the solar system, Moon and day and night

In Year 5, children learn how the Earth, the Moon and the other planets move in relation to the Sun, and that the Sun, Earth and Moon are approximately spherical. The big idea is that the Earth spins, which explains day and night and why the Sun appears to travel across the sky.

The solar system, the Moon and day and night, explained

The Sun is a star at the centre of our solar system. Eight planets orbit it: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Pluto was once counted as a ninth planet but was reclassified as a dwarf planet in 2006, which is a good reminder that science changes when we find out more. An orbit is the path one body takes around another, and the planets all travel around the Sun in the same direction. The further a planet is from the Sun, the longer its year: Mercury takes 88 Earth days to go round, Earth takes a year and Neptune takes about 165 Earth years.

Children are expected to describe the Sun, Earth and Moon as approximately spherical, which means nearly ball-shaped. “Approximately” is the important word: they are not perfect spheres, but they are much closer to a ball than to a flat disc. Children are then asked to describe how the Moon moves relative to the Earth. It orbits the Earth, taking a little over 27 days to go round once, and it is called a moon because it orbits a planet. The Moon makes no light of its own. We see it because it reflects sunlight, and the shape we see changes over about a month as we view its lit half from different angles.

The core explanation is about the Earth’s rotation. The Earth spins on its axis, an imaginary line through the North and South Poles, once about every 24 hours. At any moment the half of the Earth facing the Sun has daytime and the half facing away has night. Because the Earth turns, a place such as Britain moves into the light (sunrise), faces the Sun most directly in the middle of the day, and turns away again (sunset). The Sun doesn’t really travel across the sky. It only appears to, because we are standing on a moving planet. This is why the Sun seems to rise in the east and set in the west, and why shadows are long in the morning and evening and shortest around the middle of the day. Meanwhile, the Earth takes a year to orbit the Sun.

Many schools also look at history: how people once believed the Earth was at the centre of everything (the geocentric model, associated with Ptolemy) and how later thinkers changed that picture. Which names a school chooses varies: Alhazen (Ibn al-Haytham), who questioned parts of Ptolemy’s model, and Copernicus, who put the Sun at the centre (the heliocentric model), are common choices. Children are told never to look directly at the Sun, and never through binoculars or a telescope. Sunglasses do not make it safe. Looking at the Sun can permanently damage eyes.

Words your child will hear

Orbit: The curved path one object takes around another, such as the Earth around the Sun.
Rotate: To spin around an axis. The Earth rotates once about every 24 hours.
Axis: The imaginary line through the Earth from the North Pole to the South Pole that it spins around.
Star: A huge ball of hot gas that gives out its own light. The Sun is our nearest star.
Sphere: A round, ball shape. The Earth is approximately spherical.
Heliocentric and geocentric: Sun-centred and Earth-centred ideas of how the solar system is arranged.
Dwarf planet: A small, round body that orbits the Sun but is not one of the eight planets, such as Pluto.

What the National Curriculum says

In Year 5, pupils should be taught to:

Describe the movement of the Earth and other planets relative to the sun in the solar system
Describe the movement of the moon relative to the Earth
Describe the sun, Earth and moon as approximately spherical bodies
Use the idea of the Earth's rotation to explain day and night and the apparent movement of the sun across the sky

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

Try it: modelling day and night

Using a torch and a ball, how can you explain why the Sun appears to move across the sky?

Set up the model. A torch (or a lamp with the shade off) is the Sun. A ball or globe is the Earth. Stick a small piece of paper or a sticker on the ball to show where you live. Darken the room.
Light the ball from one side. Half the ball is bright and half is dark. This shows that at any time half of the Earth has day and half has night. Check which half the sticker is in.
Spin the ball slowly, keeping the torch still. Hold it with the North Pole at the top and turn it anticlockwise as you look down on the North Pole, which is the way the real Earth spins.
Watch the sticker. It moves into the light, which is sunrise. It faces the torch, which is the middle of the day. It slides out of the light, which is sunset. Then it spends a while in the dark: night.
Link back to the sky. From the sticker’s point of view, the torch seems to appear on one side, pass across and disappear on the other. In real life it is the ball that moves, not the Sun.

The Earth rotates once about every 24 hours. As it turns, our part of the Earth moves into the Sun’s light and then out of it, so we get day and night. The Sun only appears to move across the sky, rising in the east and setting in the west, because we are turning with the Earth.

Common mistakes and how to help

Thinking the Sun moves around the Earth

That is exactly what we see every day. The Sun rises, travels across the sky and sets, while the ground feels completely still.

What helps: Use the torch and ball model, and talk about how a train window makes the platform seem to slide past. Explain that people believed the Sun moved around the Earth for centuries.

Believing night happens because the Sun goes away, or the Moon blocks the Sun

Children can see the Sun leave the sky and the Moon appear, so they link the two.

What helps: Point out that the Sun is still shining. Night is just our half of the Earth turned away from it. Check with the globe or ball and the torch.

Thinking the Moon only comes out at night, or makes its own light

We notice the bright Moon in a dark sky, but not the pale Moon on a clear afternoon.

What helps: Look for the Moon during the daytime. Ask what the Moon would look like in a dark cupboard with no torch, to show that it only reflects sunlight.

Picturing the planets as close together and about the same size

Diagrams squeeze the solar system onto a page, and the planets are drawn big enough to see.

What helps: Make a line of distances along a corridor or garden. Space is mostly empty, with huge gaps between the planets.

How to help at home

Torch and ball model. Repeat the day and night model in a dark room with a torch and any ball. Take turns being the Earth and spinning slowly on the spot, and talk about when your side of the room is in the light.
Shadow stick. Push a stick upright into the lawn, or stand it in a pot, on a sunny day, and mark the end of its shadow with chalk or a stone every hour. The shadow gets shorter towards the middle of the day, then longer again, and it moves round as the Earth turns. Never look at the Sun to do this.
Moon diary. Draw the Moon’s shape whenever you can see it over a few weeks, noting the time and where it is in the sky, and look for it in the daytime too. Ask your child to say which part is lit and why.
Make a solar system walk. Mark the Sun at one end of the garden or park and place the eight planets along a path using stones or items from the kitchen. Count the steps between them and notice how far apart the outer planets are.
Planets in order. Invent a silly sentence whose words start with the planets’ initial letters, from Mercury outwards. Then ask your child to explain why Pluto isn’t on the list, which is a good chance to talk about how science changes.

Everything in Year 5 science

Updated 20 October 2026.