Learning about levers through beam and mass

In this fun practical experiment students will predict and measure the reaction forces occurring when a mass is attached at various positions along a beam. They’ll explore this by making a lever using a metre rule, luggage scale and a bag of sugar. The activity is a great way of exploring the physics behind levers in a hands-on and engaging way.

This is one of a set of resources developed to aid the teaching of the secondary national curriculum, particularly KS3, supporting the teaching in science (physics) and maths.

Activity: Calculating moments using a metre rule, luggage scale and a bag of sugar

Students will attach a bag of sugar to a beam balanced on a hinge support, using a luggage scale to measure the reaction at the other end. Students must then make calculations to predict the reading on the scale when the hanging mass is placed at various positions along the beam before comparing and discussing the results.

Download our activity overview for a detailed lesson plan and worksheet for teaching students about calculating moments.

The engineering context

Engineers use the principles of levers and moments to design and construct buildings, bridges, and other structures, ensuring that they’re able to withstand various forces and loads. The Heatherwick rolling bridge and the Shard building are examples of structures that rely on understanding moments. Knowing about moments is also essential in understanding how levers work, such as using a seesaw or wheelbarrow, or lifting weights using your biceps.

Suggested learning outcomes

Students will learn how the position of a mass along a beam affects the reaction force. They will also be able to draw a force diagram, calculate moments, and understand the principle of equilibrium in the context of beams.

Download our activity sheet and other teaching resources

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.

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.

Download our classroom lesson plan below.

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