Exploring Light and Shadows

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Overview

Year Level: Year 3
Subject: Science
Duration: 30 minutes
Class Size: 28 students
Australian Curriculum Code: ACSSU048
Content Description:

• Students investigate how light from a source forms shadows and can be absorbed, reflected, and refracted.

General Capabilities:

• Critical and Creative Thinking
• Scientific Understanding
• Literacy
• Numeracy

Cross-curriculum Priorities:

• Sustainability: Understanding natural phenomena
• Aboriginal and Torres Strait Islander Histories and Cultures: Opportunity to incorporate traditional understandings of natural sciences.

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Learning Intentions

By the end of the lesson, students will:

• Understand how shadows are formed.
• Observe how the length and direction of a shadow change depending on the light source's angle.
• Accurately measure and record scientific observations.
• Collaborate in small teams to investigate light behaviour.

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Success Criteria

Students will:

• Predict and explain how different angles of light affect shadow length.
• Use rulers and informal units to measure shadows.
• Record data using a structured observation chart.
• Use scientific vocabulary like ‘opaque’, ‘translucent’, ‘light source’, and ‘shadow’.

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Materials Required

• Per group (4 students each):

  • Torch or LED flashlight
  • Ruler (30 cm)
  • Protractor (or pre-marked angles on cardboard)
  • A4 recording sheet (provided)
  • Pencil
  • Small opaque toy/figurine (approx. 10–15 cm tall)

• Teacher Preparation:

  • Dim classroom lighting or use a shaded area outside
  • Shadow Experiment Recording Sheets
  • Mark three light angles on protractors or cut-out angle guides: 30°, 60°, and 90°

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Lesson Structure

1. Tuning In (5 minutes)

Engage and Connect—Interactive Demonstration
Teacher explains:

• Light travels in straight lines.
• Shadows form when light is blocked by an object.
• The shape, size and direction of shadows depend on the position and angle of the light source.

Mini-Demo:
Shine a torch on a small opaque object at different angles. Ask:

• What do you notice as I move the torch lower or higher?
• Are the shadows longer or shorter?

Introduce today’s challenge:
👉 “Scientifically measure and record how shadows change based on light angles!”

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2. Exploring (20 minutes)

Group Activity – Rotate Between Light Angles

Set-up (2 minutes):
Students split into 7 groups (4 students per group). Each group has:

• Torch
• Opaque figurine
• Angle indicator
• Ruler and recording sheet

Investigation (15 minutes):
Students test shadow lengths at three different light angles: 30°, 60°, and 90°. They shine the torch at those angles while keeping the object in the same position on the workspace.

STEP-BY-STEP:

1. Place object at centre marker.
2. Shine the torch at 30°.
3. Measure and record shadow length.
4. Repeat with 60° and 90°.
5. Observe: Does the shadow point in different directions?
6. Optional Advanced Challenge: Try with a translucent object (like a coloured plastic block). Does the shadow change?

Roles within Each Group:

• Light Controller (positions torch)
• Shadow Measurer (uses ruler)
• Recorder (writes down data)
• Timekeeper (ensures even time at each station)

Data to Record:

Light Angle	Shadow Length (cm)	Shadow Direction	Notes (e.g., clear or fuzzy)
30°
60°
90°

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3. Reflecting (5 minutes)

Discussion and Wrap-Up

Gather back together as a class. Prompt discussion:

• “What did you notice about the size of the shadow at different angles?”
• “Which shadow was longest? Why do you think that happens?”
• “Did all your groups get similar results? Why or why not?”

Key Teaching Point:
The lower the light source (e.g., 30°), the longer the shadow. As the light source rises (e.g., 90°—directly overhead), the shadow shortens.

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Assessment

Formative:

• Monitor teamwork and engagement during activity.
• Review group recording sheets for accuracy.
• Listen for correct use of scientific terms during discussion.

Teacher Checklist:
✅ Used ruler correctly?
✅ Repeated light angles as instructed?
✅ Recorded observations clearly?
✅ Able to explain what caused the shadow changes?

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Differentiation

• Support: Provide visual step-by-step prompt cards. Allow alternative ways to record observations (e.g., drawing instead of writing).
• Extend: Challenge early finishers to experiment with transparent or translucent objects and compare shadow clarity. Ask them to graph results.

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Possible Follow-Up

• Outdoor Shadow Mapping: Track the Sun’s shadow from a fixed object at different times of the day.
• Art & Science Integration: Use chalk to trace shadows outside and explore how artists use light and shadow.
• Cultural Insight: Explore how Aboriginal and Torres Strait Islander peoples interpret the play of light and shadow in stories or seasonal knowledge.

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Teacher Reflection Notes (fill in post-lesson)

• What worked well?
• Which group surprised you?
• Were all students able to explain the phenomenon?
• Any need to revisit measurement skills?

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Bonus Twist: Science Anchor Wall

Add a classroom “Shadow Detectives” board to display vocabulary, student predictions, and sketch results. Keep it growing throughout the light unit!

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