Start of main content
Age range: 7-11
Duration: 30-59 mins
  • Maths
  • Science

Lighter by far

Investigating how the light from a torch changes with distance

This is one of a set of resources developed to support the teaching of the primary national curriculum. They are designed to support the delivery of key topics within science, design and technology, and maths (in this case, mainly science). This resource focusses on the investigation of how the light from a torch (flashlight) changes with distance.

Light is a type of electromagnetic radiation. Visible light is the range of the electromagnetic spectrum that can be seen with a human eye. The brightness, or intensity, of light is typically measured as the power per unit area.

The lamp in a torch produces light when it is supplied with electricity. This light from a lamp would normally extend out in every direction, so a torch typically uses reflective materials, such as the inside of a silvered cone, to aim it where it is desired. However, this focus is rarely perfect, and the light spreads out as the distance from the lamp increases.

Activity info, teachers' notes and curriculum links

In this activity learners will carry out an experiment to measure how the light from a torch changes with the distance from the lamp. They will record their results in a table and plot a graph.

This could be used as a one-off activity in science or linked to maths learning about tables and graphs. It could also be used in conjunction with the IET primary activity ‘Stylish Shadows’, which involves making shadow puppets.

The activity sheet includes teachers' notes, useful web links, and links (where appropriate) to the national curriculum in each of the four devolved nations; England, Northern Ireland, Scotland and Wales.

Download the free activity sheet below!

All activity sheets and supporting resources are free to download, and all the documents are fully editable, so you can tailor them to your students' and your schools' needs.

And please do share your classroom learning highlights with us @IETeducation

Available downloads

Download all the above

Related resources