Why does a torch disappear when one hole in a row of cards moves sideways? Trace light from a source to an eye and explain observations using straight rays.

Pupils try “Align a beam through three holes”. Includes the editable PowerPoint, a 50-minute lesson plan and a printable pupil sheet with equipment, instructions, example evidence and worked teacher answers.

KS3 physics for ages 11–14. Part of the light, colour and vision sequence.