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What is light?

What is light? Sunset image
Light, reflection and shadows are all part of primary-school science. Find out how children learn about light and how you can support your child's science learning at home in primary-school teacher Catherine Casey's guide for parents.

What is light?

Light is a type of energy that makes it possible for us to see the world around us.

We need light to see. Light comes from different sources called light sources; our main natural light source is the sun. Other sources include fire, stars and man-made light sources such as light-bulbs and torches.  

Thanks to light, we see life in glorious colour: our eyes see different wavelengths of light as different colours.

Light also powers the technology around us: laser beams make CD and DVD players and printers possible, microscopes and telescopes use lenses to bend light (refraction), cameras record light as it reflects off objects and fibre-optic cables and lasers allow us to communicate at incredible speed.

What are children taught about light in primary school?

At primary school children will explore how light behaves, including reflection, shadows and how we see things.

Reflection is how we use light to see around us.

Reflection is when light hits the surface of an object and then that light travels to our eyes so we can see. The reflected light from objects is absorbed by our eyes to form images of the world around us. Smooth surfaces such as mirrors, water and some metals reflect the most light which is why they appear shiny.

The moon reflects sunlight so we can see it shining brightly in the sky. 

Shadows are created when an opaque (non see-through) object blocks the light source. Shadows change depending on the distance the object is from the light source and the position of the light source.

Light appears to travel in straight lines, travelling from light sources until it hits the surface of an object. 

When are children taught about light?

In Year 1 children explore materials and may use the terms opaque (non see-through) and transparent (see-through) to describe different materials.

In Year 3 children begin to fully explore ‘light’. The new National Curriculum, introduced in 2014, requires children in Year 3 to understand that they need light to see and that light is reflected from surfaces. They will explore shadows and learn how shadows are formed when a light source is blocked by an opaque item. Children will consider the dangers of looking directly at light sources (mainly the sun) and how they can protect their eyes.

In Year 6 children consolidate their knowledge of light gained in Y3. They extend this understanding by learning about how light travels in straight lines. They will learn how we see, by understanding light travels from the light source to an object and then reflects to our eyes. Children consider why shadows have the same shape as the object that made them. Children may also explore rainbows, colours in bubbles and light appearing to bend in water.

How are children taught about light?

Children will learn about light from a range of sources such as the internet, information books and presentations.

In Year 3 they may be asked to complete activities such as identifying light sources by playing ICT games, practically sorting light sources or pictures. They will explore light practically by looking for and creating shadows using sunlight and torches. Children will learn through carrying out scientific investigations and experiments, for example looking at what happens to shadows when a light source moves or the distance between the light source and an object changes. They may explore mirrors to learn how light behaves.

In Year 6 children continue to develop their understanding of light and might make a periscope (a device used to see things that are out of sight), create shadow puppets or explore and create rainbows using different lenses.

Books about light for children


Learn about light with activities at home:

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