Colour and Light

Active learning works well for this topic because students need to see colour and light in action to grasp abstract concepts. Hands-on prism and filter activities let them test ideas immediately, turning observations into understanding. Group discussions help them connect what they see with how they describe it.

• Primary 4
• Science
• 4 activities
• 25 min–40 min

Learning Objectives

1. Explain how white light can be separated into its constituent colours using a prism.
2. Predict the resulting colour when two primary coloured lights (red, green, blue) are mixed.
3. Compare the appearance of a coloured object under different coloured lights, identifying whether it appears black, its original colour, or another colour.
4. Analyze how coloured lights are used in specific applications, such as theatre lighting or traffic signals, to create effects or convey information.

Experiential Learning

⏱ 30 min·Pairs

Prism Exploration: Splitting White Light

Provide prisms for pairs to direct sunlight or torchlight through and observe the spectrum on white paper. Students record the colour order and sketch the rainbow. Discuss how this shows white light contains all colours.

Prepare & details

Explain how white light is made up of different colours.

Facilitation Tip: During Prism Exploration, move around the room to adjust prisms and help students trace the spectrum with pencils on paper so they document their observations.

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

⏱ 40 min·Small Groups

Filter Testing: Object Colours Under Lights

Set up torches covered in red, blue, and green cellophane. Pairs shine each on coloured paper, fabric, and toys, predicting and noting appearances in tables. Groups share findings to identify patterns.

Prepare & details

Predict the colour an object will appear under different coloured lights.

Facilitation Tip: During Filter Testing, have students work in pairs to discuss why a red object looks black under blue light before testing their ideas with torches and filters.

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

⏱ 35 min·Small Groups

Additive Mixing: Coloured Light Projections

In small groups, project red, green, and blue lights onto a white screen using torches and filters. Overlap beams to create new colours and photograph results. Students explain mixtures with colour wheels.

Prepare & details

Analyze the use of coloured lights in everyday applications like stage lighting.

Facilitation Tip: During Additive Mixing, dim the lights to make colour overlaps clearer and ask students to sketch their predictions before testing them.

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

Stage Lighting Simulation: Whole Class Demo

Use coloured spotlights on classroom objects or student volunteers. Class predicts appearances, then observes and votes on explanations. Record uses in theatre or festivals.

Prepare & details

Explain how white light is made up of different colours.

Facilitation Tip: For Stage Lighting Simulation, use a white wall as a screen and have students take turns adjusting torch angles to create specific colours.

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 by letting students experience colour and light first, then name the science behind it. Avoid starting with definitions; instead, let observations drive vocabulary. Research shows that students grasp additive colour best when they see light blends before hearing the term. Keep demonstrations visible to the whole class so everyone can follow along and ask questions.

What to Expect

Successful learning looks like students confidently explaining that white light contains all colours, predicting how objects change under coloured lights, and using terms like absorption and reflection. They should also distinguish additive light mixing from subtractive paint mixing with clear examples.

Watch Out for These Misconceptions

Common Misconception

During Prism Exploration, watch for students who think the prism adds colour to white light instead of revealing colours already present.

What to Teach Instead

Ask students to trace the spectrum on paper and predict what happens if they block one colour with a card, guiding them to see the prism separates existing wavelengths.

Common Misconception

During Additive Mixing, watch for students who believe mixing all paint colours is the same as mixing all light colours.

What to Teach Instead

Set up a side-by-side comparison: have students mix red, green, and blue torches to make white, then mix red, yellow, and blue paints to make brown, prompting discussion on why the results differ.

Common Misconception

During Prism Exploration, watch for students who think white light has no colour until split by the prism.

What to Teach Instead

Have students hold the prism close to their eyes and describe the rainbow they see without the prism separating it, reinforcing that white light contains all colours together.

Assessment Ideas

Quick Check

After Additive Mixing, present students with red and green torches and ask them to predict the colour on the screen, then record their observations and explanations in their science notebooks.

Exit Ticket

After Filter Testing, give each student a blue filter and a red object. Ask them to predict how the object will look through the filter and write their reasoning based on absorption and reflection before leaving class.

Discussion Prompt

During Stage Lighting Simulation, ask students to explain how they would use coloured lights to make a singer stand out, ensuring they use terms like 'additive mixing' and 'absorption' in their answers.

Extensions & Scaffolding

• Challenge early finishers to create a colour wheel with torches and filters, explaining how each segment mixes to form white light.
• For students who struggle, provide pre-printed spectrum diagrams where they can colour-match the light bands seen through the prism.
• Deeper exploration: Have students research how screens (TVs, phones) use RGB pixels to create all colours, then compare this to their torch mixing results.

Key Vocabulary

Spectrum	The range of colours that make up white light, which can be seen when light is passed through a prism.
Additive colour mixing	The process of mixing coloured lights, where combining lights of different colours produces a lighter colour, eventually white.
Absorption	The process where an object takes in certain colours of light and reflects others, determining the colour we see.
Reflection	The bouncing of light off a surface; the colour of light that is reflected determines the colour of the object.