Light and Colour

Active learning builds lasting understanding in light and colour because hands-on experiments let students see abstract ideas in real time. When students manipulate prisms and filters themselves, they move from guessing about colours to observing how light splits and interacts with objects.

• Year 3
• Science
• 4 activities
• 20 min–45 min

Learning Objectives

1. Demonstrate how white light can be separated into a spectrum of colours using a prism.
2. Explain that objects appear a certain colour because they reflect specific wavelengths of light and absorb others.
3. Predict the apparent colour of an object when viewed under different coloured lights.
4. Classify colours as primary or secondary based on how they combine.

Stations Rotation

⏱ 45 min·Small Groups

Stations Rotation: Prism Rainbows

Prepare stations with prisms, torches, and white paper. Students shine light through prisms to project spectra, measure band widths, and note colour order. Rotate groups every 10 minutes, then discuss patterns as a class.

Prepare & details

Explain why a rainbow appears after rain.

Facilitation Tip: During Prism Rainbows, circulate and ask each group to predict which colour will appear first in the spectrum before they shine the light.

Setup: Tables/desks arranged in 4-6 distinct stations around room

Materials: Station instruction cards, Different materials per station, Rotation timer

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Experiential Learning

⏱ 30 min·Pairs

Pairs Investigation: Coloured Shadows

Provide torches, cellophane filters in red, blue, green, and white objects like toys. Pairs predict and test shadow colours on walls, record results in tables. Share findings to identify rules.

Prepare & details

Differentiate between primary and secondary colours of light.

Facilitation Tip: During Coloured Shadows, remind pairs to record their predictions before testing, then compare results to their initial ideas.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 25 min·Whole Class

Whole Class: Filter Prediction Challenge

Display objects under a projector with coloured filters. Class predicts appearances before revealing, votes on answers, then tests with handheld torches. Chart predictions versus observations.

Prepare & details

Predict what colour an object would appear under different coloured lights.

Facilitation Tip: During the Filter Prediction Challenge, provide one wrong prediction example to the class and ask students to explain why it’s incorrect using the filters they’ve tested.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 20 min·Individual

Individual: Rainbow Journal

Students draw observed rainbows from prisms, label colours, and write explanations of raindrop roles. Include photos or sketches from outdoor hunts after rain.

Prepare & details

Explain why a rainbow appears after rain.

Facilitation Tip: In Rainbow Journal, model how to label diagrams with terms like refraction and absorption before students begin their entries.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Teaching This Topic

Teach this topic through cycles of prediction, testing, and explanation to build scientific reasoning. Avoid giving answers too quickly; instead, guide students to notice patterns in their observations. Research shows that students grasp light behaviour best when they manipulate materials themselves and explain their findings to peers.

What to Expect

Successful learning looks like students confidently explaining why white light splits into colours, predicting how objects appear under different coloured lights, and using terms like reflection and absorption in their discussions. Their journals should show clear diagrams and accurate observations from each station.

Watch Out for These Misconceptions

Common Misconception

During Prism Rainbows, watch for students who think the prism contains colours inside itself.

What to Teach Instead

Hand each group a torch and prism, then ask them to predict what colours they will see before shining the light. Encourage them to trace the light path and note that the colours emerge as sunlight splits, not from the prism itself.

Common Misconception

During Coloured Shadows, watch for students who believe shadows are always black.

What to Teach Instead

Provide coloured filters and objects, then ask students to predict shadow colours before testing. Guide them to observe that shadows take on the colour of the light blocked, not just black.

Common Misconception

During the Filter Prediction Challenge, watch for students who confuse light colour mixing with paint mixing.

What to Teach Instead

Give each pair two overlapping filters and ask them to predict the resulting colour. Have them test with a white surface to see that light colours add, unlike paint, which subtracts colours.

Assessment Ideas

Exit Ticket

After Prism Rainbows, provide each student with a small prism and a torch. Ask them to draw what they observe when shining the light through the prism onto a white surface and label at least three colours they see in the spectrum.

Quick Check

During Coloured Shadows, show students a red object and ask: 'If I shine a blue light on this red object, what colour will it appear? Explain your answer.' Listen for explanations involving reflection and absorption of light wavelengths.

Discussion Prompt

After the Filter Prediction Challenge, pose the question: 'Why do we see a green leaf as green, but it looks black under a red light?' Facilitate a class discussion where students use terms like reflection and absorption to explain their reasoning, referencing their filter tests.

Extensions & Scaffolding

• Challenge early finishers to combine two filters and predict the resulting light colour before testing their idea.
• Scaffolding for struggling learners: Provide a word bank with terms like reflect, absorb, and spectrum to support their journal entries.
• Deeper exploration: Ask students to research how rainbows form in nature and compare it to their prism activity using a short written or visual comparison.

Key Vocabulary

spectrum	The range of colours that make up white light, visible when light is split, like in a rainbow.
refraction	The bending of light as it passes from one substance to another, such as from air into a prism or raindrop.
reflection	The bouncing of light off a surface. The colour we see is the light that is reflected.
absorption	The process where light energy is taken in by an object, rather than being reflected or transmitted.
primary colours of light	The basic colours of light (red, green, and blue) that can be mixed together to create other colours.
secondary colours of light	Colours made by mixing two primary colours of light, such as cyan (blue + green), magenta (blue + red), and yellow (red + green).