Strand: Energy and Forces

Lesson: Light

Aim/Objectives

1. To increase pupils' knowledge of light sources.
2. To enable pupils to understand the difference between transparent, translucent and opaque.

Materials Needed

Lap-top and projector,
Textbook: 'Look Around' Folens - 3rd and 4th classes
CD Rom: Mad About Science, Disc 1 - Energy (DK)
Materials which are transparent (glass) translucent (tissue paper, lamp shade) and opaque (sunhat)
Light sources: candle, electric lamp, torch, and sun picture

 
Content/Methodology

Introduction

Introduce lesson using a K.W. L with pupils

K: What they know ....( about topic)
W: What they would like to know .... ( a question)
L: What they have learned.... (revision)

Development

Show materials, tissue paper, lamp shade, sun hat, clear glass, frosted glass, plastic clear and coloured.

Establish to what extent light can pass through them- fully, a little, or not at all. Summarise results into three categories explaining terms transparent, translucent and opaque. Discuss ordinary materials in the home in terms of these three categories eg blinds are made of opaque or transparent material to block out the light.

Set up laptop and projector. Insert CD. Click on Light - Section 22: Where does light come from?

Children are asked through an interactive game to group objects into those objects which make light and those which do not, eg flame, torch (batteries) lamp (electricity and bulb) and sun are light sources. Silver, gold paper and mirrors reflect light rather than make light.

Section 23: Travelling light - Shadows

Children are asked to test materials (glass, tracing paper, wood, and solid object) to see if light can pass through them. The solid object (and wood) do not allow light to pass through them but the solid object (a spanner) casts a shadow on the wall. This occurs as light travels in straight lines and does not bend around the contours of the object.

Children discuss how shadows are formed.

Conclusion/Follow Up Activities

Further experiments:
(1) Observe the effect of putting a pencil/paintbrush in water - light and water appear to split the pencil.
(2) Make a spectrum or colour wheel, twirl very fast and observe the effect when colours blend.

Discuss and record results

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