Section 1: ο»ΏUnderstanding vision and optical devices requires a knowledge of how light behaves.ο»Ώ

Key Ideas     Unit Checklist

  Unit C: Section 1 – Introduction


Figure C.S.1.1 – Peyto Lake in Banff National Park reflects bright blue light.

Figure C.S.1.2 – A red cardinal bird’s feathers reflect red light.


Figure C.S.1.3 – Objects reflect their colour of light.
What is Colour?

The ability to detect and reflect different colours is an important adaptation for animals and people. Colour helps some animals tell the difference between objects. For example, brightly coloured flowers attract insects for pollination. Colour helps animals see food easier, such as brightly coloured fruit. Some animals have colours that help them blend into their surroundings so they don’t get eaten by predators. So how is it that different living things and objects have different colours?

Objects that don’t produce light, reflect light. Light from the Sun is white light, which contains all colours of light. An object appears as the colour of light that it reflects. For example, Peyto Lake in Banff National Park is a bright turquoise blue colour. Peyto Lake is so bright compared to other lakes because it contains lots of glacial sediments. The tiny sediments and water reflect turquoise blue light, and absorb all other colours of light.

 Watch More

Colour Me Curious

This video explains why objects appear the colour of the light waves they reflect.

 
 
 
 
Now that you know more about colour, why do you think the sky is blue? Watch this video to check your answer.

 
 
 
 
Why can water look both colourless or blue? Watch these two videos to find out.

 
 
 
 
 
 

  Words to Think About:

Check out the word cloud below. It pictures the important words that you are going to learn in this section. Watch for these words, and combinations of these words, as you read. When you see them highlighted, you can click on them to learn more about what the word means. You can also visit the course glossary and read definitions for all of these words.


Lessons in This Section

Lesson C1: Solving the Riddle of Light and Vision
Key Question – How has human understanding of light changed over time?
 
Lesson C2: Light Properties and Technologies
Key Question – What are some modern technologies that use light?
 Lesson C3: Optical Devices
Key Question – How do microscopes, telescopes, and binoculars use light to make images?
Reading and Materials for This Section

Science in Action 8
Reading: Pages 174–187

Materials Lists for Unit:
Master List of all materials
Materials organized by lesson and activity

 Think β€’ Interpret β€’ Decide 

Colour Absorption and Reflection

The video shows a simple experiment that uses coloured lasers to pop different coloured balloons. As you watch the video, pause and answer the questions asked by the video narrator.
 

 
Questions:

After you have finished watching the video, carefully consider the following questions. Then, type or write your answers. When you have your answers, click the questions for feedback.

Think: Red light from the laser did not pop red or white balloons. Red light from the laser popped blue balloons.
Interpret: Coloured balloons reflect the same colour of light energy as their surface, and absorb all other colours. The red balloon reflected red light, so it did not heat up enough to pop. The blue balloon absorbed red light. This energy melted a hole in the balloon, popping it. The white balloon reflected all colours of light. The white balloon did not absorb light energy, so it did not pop. A black balloon would absorb all colours of light energy, which would cause the balloon to pop.
Decide: Coloured light reflects off objects which appear as that colour. Coloured light is absorbed by objects that have a different colour to the light. White objects reflect all colours of light. Black objects absorb all colours of light.