Unit 15 Light, Colours and Beyond

Topic

A colourful life

Curriculum Link

15.3 Colour

Estimated Lesson Time

80 minutes

Introduction

In this activity, the concepts of 'coloured lights' and 'coloured inks' are introduced to students.  At first, students are engaged to phenomenon with colours by conducting  interesting experiments. Then they will explore the concepts of coloured lights using coloured filters and mixing coloured lights. Finally, students are guided to distinguish the concepts of 'coloured lights' and 'coloure inks' by considering the concept of black colour.

Key Question

How to create a colourful world?

Learning Objectives

In this activity, the students should be able to

  1. know and explain the colour spectrum of light (SP1) ;
  2. make light spectrum using prism (SP4);
  3. recognise that all colours can be obtained by mixing the three primary colours (SP4) ;
  4. understand how we perceive colours.

Teaching Plan

Task (Time) Brief Description Materials Objectives

Engagement
& Exploration
(30 min)

Student are engaged to attend to the concept of colour in Task 1 :

  1. A charming experiment to introduce colour in our life.
    Reference:
    https://www.youtube.com/watch?v=mc5ljuG4FYE
    http://www.kidzone.ws/science/rainbow.htm

  2. Ask students produce spectrum by using ray box and a prism on a white paper.
    Reference:
    https://www.youtube.com/watch?v=uucYGK_Ymp
 (1) & (2)

Explanation
(15 min)

Teacher explains how we perceive colours

  1. Three types of colour-sensitive cone cells in our retina each responds best to red, blue and green colour of lights.
  2. Colour blindness as a genetic disease caused by defects in some cone cells.
  3. The principle of colour TV
    Computer simulation:
    http://www.omsi.edu/tech/colormix.php
  • PowerPoint
 (4)

Exploration
(20 min)

Task 2: Students explore the mixing of coloured light

  1. Use blue, red and green filters to covers three torches with white LED to produce light of primary colours.
  2. Mix the primary coloured ight in different ways
  3. Study how objects appeared to be different colours
 (3)

Exploration &
Explanation
(15 min)

In Task 3, students explore the difference between coloured lights and colour ink.

Ask students to elaborate the

"What coloured light will be produced if all three colour filters cover a torch?"

"White light consists of seven coloured lights. Why T-shirt with red ink/pigment appears to be red colour?"

 (2) & (3)

*Apparatus and materials required: