Light and Shadows — Year 3 Lesson Plan
National Curriculum: Science — Light: recognise that light appears to travel in straight lines, Year 3
Overview
Pupils investigate how light travels in straight lines and explore the relationship between light sources, opaque objects, and shadows. They discover how the size and position of a shadow change as the light source moves, and learn about reflection and the danger of looking directly at the sun.
Learning Objectives
- Recognise that light travels in straight lines from a light source.
- Explain how shadows are formed by opaque objects blocking light.
- Investigate how shadow size and shape change as the light source moves.
- Understand that we see objects because light is reflected into our eyes.
Key Vocabulary
Suggested Lesson Structure
Ask: what do you need for a shadow to form? Collect ideas. Demonstrate with a torch and an opaque object in a darkened corner. Introduce the key question: what affects the size and shape of a shadow?
Explain that light travels in straight lines (model with a torch and a curved tube — light cannot travel around corners). Explain shadow formation: opaque object blocks straight-travelling light, creating a dark area behind it. Show how reflection allows us to see non-luminous objects.
Pupils carry out a systematic shadow investigation: hold an opaque object at different distances from a torch, measure shadow length. Record results and identify the pattern.
Pupils draw ray diagrams showing how shadows form, label the light source, opaque object, and shadow. Write a conclusion linking shadow size to distance from the light source.
Why do shadows outdoors change throughout the day? Pupils apply understanding of light source position (the Sun) to explain morning, midday, and afternoon shadow differences.
Common Misconceptions
- Pupils sometimes think shadows are a reflection of the object — clarify that a shadow is an absence of light, not an image.
- Believing that you see objects because your eyes send out beams of light — reinforce that eyes receive reflected light.
Prior Knowledge
Pupils should already be able to:
- Ability to name light sources.
- Awareness that some materials block light and some do not.
- Experience making shadows in KS1.
Want a personalised version of this lesson?
Use Staffroom to generate a complete lesson plan tailored to your class — add context about ability, recent learning, or specific pupils and get a plan ready to teach. Free trial, no card required.