The solar system: Year 5 science for parents

What it is

Solar system

The Sun and everything that travels around it, including the eight planets, their moons, dwarf planets such as Pluto, asteroids and comets.

Orbit

The path one object takes around another in space. The Earth orbits the Sun, and the Moon orbits the Earth.

Rotate

To spin around. The Earth rotates on an imaginary line through the North and South Poles, called its axis.

Spherical

Shaped like a ball. The Sun, Earth and Moon are all approximately spherical.

The Sun is a star, and it sits at the centre of our solar system. Eight planets orbit it. In order from the Sun, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Pluto used to be called the ninth planet, so you may remember it that way. In 2006 it was reclassified as a dwarf planet, which is why your child's list stops at Neptune.

• A day: the Earth spins round once in about 24 hours. The half facing the Sun has daytime, and the half facing away has night.
• A year: the Earth takes about 365 and a quarter days to orbit the Sun. The extra quarter is why we add a leap day every four years.
• The Moon: it orbits the Earth in about 27 days. The Earth has one moon; Jupiter has four large moons and many smaller ones.

How it's taught at school

Earth and space is a Year 5 topic in the national curriculum for England. Children are taught to:

• describe how the Earth and other planets move around the Sun
• describe how the Moon moves around the Earth
• describe the Sun, Earth and Moon as approximately spherical
• use the idea of the Earth's rotation to explain day and night, and why the Sun appears to move across the sky

Teachers often use a model: a lamp or torch as the Sun and a ball as the Earth. Turning the ball shows how one side moves into the light (day) while the other turns into darkness (night). The Sun doesn't really move across our sky. It looks that way because the Earth is turning, which makes the Sun appear to rise in the east and set in the west.

Many classes also look at why the Moon shines and changes shape. The Moon doesn't make its own light: it reflects light from the Sun. Half of the Moon is always lit, and as the Moon orbits the Earth we see different amounts of that lit half. These changing shapes are called the Moon's phases, from new moon to full moon and back again.

The curriculum's guidance also suggests looking at how ideas changed over time. People once thought the Earth was at the centre of everything, until astronomers such as Nicolaus Copernicus argued that the Sun is at the centre and the planets orbit it.

Common mistakes (and how to help)

Thinking the Sun moves around the Earth

It really does look that way, which is why people believed it for so long. Use the torch-and-ball model: keep the torch still and slowly spin the ball, and watch the light sweep across it.

Thinking the Moon makes its own light

The Moon shines because sunlight bounces off it, a bit like a bike reflector caught in a car's headlights. Without the Sun, we wouldn't see it at all.

Thinking the Earth's shadow causes the Moon's phases

The phases come from where the Moon is in its orbit, compared with the Sun and the Earth. Half the Moon is always lit by the Sun, and the phase is simply how much of that lit half is facing us.

Thinking it's summer when the Earth is closest to the Sun

It's a very common belief, among grown-ups too. Seasons are caused by the Earth's tilted axis, which leans our half of the world towards the Sun for part of the year. This goes beyond Year 5, so there's no need to push it.

Three quick activities at home

Questions parents ask

Sources

1. Department for Education: National curriculum in England: science programmes of study
2. BBC Bitesize: Day and night
3. BBC Bitesize: The Moon
4. BBC Bitesize: What is the Solar System?
5. NASA: Earth: facts
6. NASA: Earth's Moon: facts