Enlargements Starter and Main Activity

An engaging GCSE starter and main activity introducing enlargements through shadows, scale factors and coordinate links with clear reasoning throughout.

• Ideal introductory lesson for GCSE enlargements
• Real life context using shadows to build understanding
• Encourages clear explanation and mathematical reasoning
• Quick calculation tasks promoting accuracy and fluency
• Smooth transition from practical situations to coordinates
• Fully editable activity suitable for whole class discussion
• Supports mixed ability groups with accessible entry points

This resource introduces enlargements in a clear and intuitive way using a real life scenario that helps learners understand scale factor before moving into formal coordinate work. The starter activity encourages students to sketch the setup of a projector, a hand and the wall, then describe the behaviour of the shadow as the hand moves. This develops early reasoning skills and encourages learners to talk confidently about enlargement in everyday situations.

The main activity extends this by asking learners to explain what happens to the size of the shadow when the hand is placed closer to the projector or closer to the wall. These observations support a natural understanding of proportional change and prepare learners for the idea that an enlarged image can become larger or smaller depending on position.

The quick calculation tasks help students recognise how distances and scale factors relate to each other. These questions offer opportunities to develop resilience and accuracy with numbers. Each calculation links directly to the real situation which helps learners make sense of the mathematical relationships involved.

The final task asks students to connect the behaviour of shadows with enlargements on a coordinate grid. This step encourages them to recognise how scale factor applies to diagrams and shapes they will encounter in GCSE assessments. It also helps them understand that the centre of enlargement affects how shapes appear, just as the position of the hand affects the shadow.

This resource can be used as an engaging introduction before teaching formal enlargement or as a warm up for lessons on transformations more widely. It works well for mixed ability classes because it allows confident learners to reason more deeply while offering accessible entry points for those who find the topic challenging. The activity promotes discussion, thoughtful explanation and careful use of mathematical language.