Light: Sources and Shadows

Active learning works for this topic because students need direct experience with light’s behavior to build accurate mental models. Moving objects, measuring distances, and observing shadows in real time help them see how light travels and creates shadows, turning abstract ideas into concrete understanding.

• Year 3
• Science
• 4 activities
• 20 min–50 min

Learning Objectives

1. Identify natural and artificial light sources in a given environment.
2. Explain how light travels in straight lines to form shadows.
3. Compare the characteristics of shadows cast by different objects and light sources.
4. Design an investigation to observe how changing the distance between an object and a light source affects shadow size.
5. Analyze why shadows change shape when an object is moved or rotated.

Stations Rotation

⏱ 45 min·Small Groups

Stations Rotation: Shadow Makers

Prepare four stations with flashlights, objects of different sizes, and white screens. At each station, students predict and test how moving the light or object changes shadow size. Groups rotate every 10 minutes, sketch results, and share findings. Conclude with a class chart of patterns.

Prepare & details

Analyze why shadows are formed when an object blocks light.

Facilitation Tip: During Shadow Makers, set up stations with objects of different shapes and sizes so students can immediately see how light blocking affects shadow formation.

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

Stations Rotation

⏱ 30 min·Pairs

Pairs Experiment: Light Distance Test

Partners use a flashlight, toy, and wall to measure shadow lengths at three distances. They record data in a table, then switch roles to test object distance. Discuss which change has a bigger effect on shadow size.

Prepare & details

Compare the light produced by the sun to the light from a flashlight.

Facilitation Tip: In Light Distance Test, have pairs measure distances with rulers and record shadow lengths on a simple chart to make patterns visible.

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

Stations Rotation

⏱ 50 min·Whole Class

Whole Class: Outdoor Shadow Hunt

Students mark positions with chalk to trace their shadows at different times. Pairs measure and compare lengths, noting sun position changes. Back inside, they draw graphs and explain patterns using straight-line light travel.

Prepare & details

Design an experiment to change the size and shape of a shadow.

Facilitation Tip: For Outdoor Shadow Hunt, provide clipboards and ask students to trace shadows at different times of day to connect sun position with shadow changes.

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

Stations Rotation

⏱ 20 min·Individual

Individual: Shadow Shape Designer

Each student uses a flashlight and cut-out shapes to project shadows on paper. They bend or twist shapes and draw the results. Share one creative shadow and describe the light-object setup.

Prepare & details

Analyze why shadows are formed when an object blocks light.

Facilitation Tip: During Shadow Shape Designer, provide cut-out shapes and flashlights so students can experiment with shadow angles and edges before designing their own shapes.

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

Teaching This Topic

Teachers should start with hands-on explorations before introducing terminology or abstract concepts. Use simple, clear language like ‘block’ and ‘straight path’ to avoid reinforcing misconceptions. Encourage students to verbalize their observations because talking through ideas helps them refine their understanding. Avoid over-explaining; let students discover patterns through guided questioning instead.

What to Expect

Successful learning looks like students confidently describing where shadows come from, explaining how shadow size changes with light distance, and accurately labeling light sources, objects, and shadows in diagrams. They should use evidence from their experiments to justify their explanations during discussions.

Watch Out for These Misconceptions

Common Misconception

During Shadow Makers, watch for students assuming shadows match object size exactly.

What to Teach Instead

Have students measure the object’s height and compare it to the shadow length at different distances. Ask them to explain why some shadows are longer or shorter, pointing to the flashlight’s position as the cause.

Common Misconception

During Light Distance Test, listen for students saying light bends around objects to create shadows.

What to Teach Instead

Ask pairs to trace the flashlight beam with their fingers from source to shadow edge. If they can’t trace a straight path, have them adjust the setup with opaque barriers to see where light stops completely.

Common Misconception

During Outdoor Shadow Hunt, note if students think all light sources (sun, lamp, flashlight) create identical shadows.

What to Teach Instead

Have students compare their traced shadows to a chart showing sun height at different times. Ask them to describe why the sun’s angle changes shadow length, while a flashlight’s fixed position does not.

Assessment Ideas

Quick Check

After Shadow Makers, provide a flashlight, small toy, and blank wall in a darkened room. Ask students to make the shadow larger, then smaller, and explain their method using the terms ‘closer’ and ‘farther’ from the light source.

Exit Ticket

After Light Distance Test, have students draw a diagram showing a flashlight, an object, and a shadow. Ask them to label each part and write one sentence explaining how the shadow was made, using evidence from their measurements.

Discussion Prompt

During Outdoor Shadow Hunt, pose the question: ‘Why does the shadow of a tall tree look longer in the morning and shorter at midday?’ Guide students to connect the sun’s position in the sky to the length and direction of the shadow.

Extensions & Scaffolding

• Challenge: Ask students to predict and test how a shadow changes when two light sources shine on the same object simultaneously.
• Scaffolding: Provide pre-drawn shadow outlines for students to fill in during Shadow Shape Designer if they struggle with accuracy.
• Deeper exploration: Have students research how artists use shadows in drawings or how sundials rely on shadow movement to tell time.

Key Vocabulary

Light Source	Anything that produces light. This can be natural, like the sun, or artificial, like a lamp.
Shadow	A dark area formed when an opaque object blocks light. Shadows are formed because light travels in straight lines.
Opaque	An object that does not allow light to pass through it. Opaque objects cast shadows.
Light Ray	A straight line representing the path that light travels from a source.