Most things around us are coloured. Leaves are green and the sky is blue.
Our eyes can detect the light coming from a source of light such as a lamp or the Sun. They can also detect the light being reflected off various objects, such as the light reflected off a butterfly.
Our eyes detect the colour of the light they receive.
There is a huge range of colours we can see. The main colours in the rainbow are red, orange, yellow, green, blue and violet. However, there are many subtle colours in between these, and many other mixtures of colours from puce to lilac.
Computer connected to the Internet (or a set of colour blindness test charts).
A Colour vision
- How many different colours do you see in this patchwork quilt?
- How many of these colours can you name?
B Colour-blindness
Colour-blindness is a problem that a small percentage of people experience. They cannot recognise certain colours (eg some people cannot recognise the difference between a red-coloured object and a green-coloured object). It is mostly males who are colour-blind, although a small number of females are colour-blind.
There are several tests for colour-blindness. One can be located on the Web at the following address.
To test yourself:
- go to http://www.geocities.com/Heartland/8833/coloreye.html
- or use the cards provided.
C Colour after images
When you stare at a coloured object in bright light (eg sunlight) for one minute, and then look directly at a sheet of white paper, you will see an image that has the 'reverse' colour of the original (ie red will appear as blue or green).
- Stare at the colour image below for one minute, and then look at a sheet of white paper.
- What colours are seen after you have been staring at the following: red, orange, yellow, green, blue or violet?
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