Science · Year 3 · Light and Shadows: Chasing the Sun · Summer Term

Light and Vision

Students will recognize that light is needed in order to see things and explore how light interacts with objects.

• National Curriculum Attainment Targets
• KS2: Science - Light

About This Topic

Reflection is not just about looking in mirrors; it is a vital property of light that affects safety and visibility. Year 3 students investigate which materials are best at reflecting light and why this is important in everyday life. This topic also covers the dangers of direct sunlight and how to protect our eyes and skin.

This unit meets the KS2 Science requirements to notice that light is reflected from surfaces and to recognise that light from the sun can be dangerous. Students learn to distinguish between 'shiny' surfaces that reflect light well and 'dull' surfaces that do not. This topic comes alive when students can physically model the patterns of reflection using mirrors and torches to direct beams of light.

Key Questions

1. Explain how light allows us to see objects.
2. Predict what would happen to our vision if light didn't reflect off surfaces.
3. Analyze the path of light from a source, to an object, and then to our eyes.

Learning Objectives

• Explain how light travels in straight lines from a source to an object.
• Analyze how different surfaces reflect or absorb light.
• Predict the formation of shadows based on the position of a light source and an opaque object.
• Compare the reflective properties of shiny and dull surfaces.
• Demonstrate how light rays interact with mirrors to change direction.

Before You Start

Properties of Light

Why: Students need a basic understanding that light travels and comes from sources before exploring how it interacts with objects.

Materials and Their Properties

Why: Understanding that different materials have different characteristics, like smoothness or color, helps students grasp why some reflect or absorb light better.

Key Vocabulary

Reflection	The bouncing of light off a surface. Shiny surfaces reflect more light than dull surfaces.
Absorption	When a surface takes in light energy instead of bouncing it back. Dark-colored objects absorb more light.
Opaque	An object that does not allow light to pass through it, creating a shadow.
Shadow	A dark area formed when an opaque object blocks light. The shape of the shadow depends on the object and the light source.
Light Source	Anything that produces light, such as the sun, a lamp, or a candle.

Watch Out for These Misconceptions

Common Misconception

Only mirrors reflect light.

What to Teach Instead

Everything we can see is reflecting at least some light, otherwise it would be invisible! Mirrors are just very good at reflecting light in one direction. Testing 'dull' objects with a very bright light helps show they reflect too.

Common Misconception

Sunglasses are just for looking cool.

What to Teach Instead

Sunglasses have a vital scientific job: they block harmful UV rays that can damage the cells in our eyes. Discussing 'invisible' light helps students understand that the sun's power isn't just about brightness.

Active Learning Ideas

Inquiry Circle: The Mirror Maze

Students use small mirrors to bounce a torch beam around corners or obstacles to hit a target. They observe that the angle the light hits the mirror is the same as the angle it leaves.

40 min·Small Groups

Stations Rotation: Safety Gear Test

In a darkened area, students use torches to test different materials (high-vis vests, denim, foil, plastic). They rank them by how well they 'glow' when light hits them to understand road safety.

30 min·Small Groups

Think-Pair-Share: Sun Safety Poster

Students discuss in pairs the three best ways to protect themselves from the sun (hats, shades, cream). they then share their 'top tip' with the class to create a safety manifesto.

20 min·Pairs

Real-World Connections

• Traffic engineers use reflective materials on road signs and markings to improve visibility at night, ensuring drivers can see hazards and directions clearly.
• Photographers use reflectors to bounce light onto their subjects, controlling shadows and illuminating faces or products for portraits and advertisements.
• Architects consider how buildings interact with light, using reflective windows to reduce heat gain or matte surfaces to prevent glare for occupants.

Assessment Ideas

Exit Ticket

Give students a card with a drawing of a flashlight, a ball, and a wall. Ask them to draw arrows showing the path of light from the flashlight to the ball and then to the wall. Include one sentence explaining why the ball casts a shadow.

Discussion Prompt

Present students with two objects: a mirror and a piece of black felt. Ask: 'Which object will reflect more light? How do you know?' Follow up with: 'What happens to the light that is not reflected?'

Quick Check

Hold up various objects (e.g., a shiny spoon, a wooden block, a clear plastic cup, a dark t-shirt). Ask students to give a thumbs up if the object is opaque and a thumbs down if light can pass through it. Then, ask them to predict if it will cast a dark or faint shadow.

Frequently Asked Questions

What makes a surface a good reflector?

Surfaces that are very smooth and shiny, like mirrors or polished metal, are the best reflectors because they bounce light back in a predictable way without scattering it.

Why do we need to be careful with sunlight?

The sun gives off powerful energy, including UV rays. These can burn our skin and damage our eyes if we look directly at the sun or stay out too long without protection.

How do high-visibility vests work?

High-vis vests are made of special 'retro-reflective' materials that bounce light directly back to the source (like car headlights), making the person wearing them appear very bright to the driver.

How can active learning help students understand reflection?

Active learning, such as the 'Mirror Maze' or testing high-vis materials, allows students to manipulate light themselves. By controlling the 'bounce' of a beam, they internalise the rules of reflection through trial and error. This hands-on approach turns a complex physics concept into an engaging, practical challenge that reinforces the link between properties and safety.

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