1. Colour
White light is not a single colour; it is made up of a mixture of the seven colours of the rainbow.
We can demonstrate this by splitting white light with a prism:
This is how rainbows are formed: sunlight is “split up” by raindrops.

2. The colours of the rainbow:
Red
Orange
Yellow
Green
Blue
Indigo
Violet

3. Adding colours
White light can be split up to make separate colours. These colours can be added together again.
The primary colours of light are red, blue and green:
Adding blue and red makes magenta (purple)
Adding blue and green makes cyan (light blue)
Adding red and green makes yellow
Adding all three makes white again

4. Only red light is reflected
Seeing colour
The colour an object appears depends on the colours of light it reflects.
For example, a red book only reflects red light:
Homework
White
light
Only red light is reflected

5. A white hat would reflect all seven colours:
A pair of purple trousers would reflect purple light (and red and blue, as purple is made up of red and blue):
Purple light
A white hat would reflect all seven colours:
White
light

6. Using coloured light
If we look at a coloured object in coloured light we see something different. For example, consider a football kit:
Shirt looks red
White
light
Shorts look blue

7. In different colours of light this kit would look different:
Red
light
Shirt looks red
Shorts look black
Shirt looks black
Blue
light
Shorts look blue

8. Some further examples:
Object
Colour of light
Colour object seems to be
Red socks
Red
Blue
Black
Green
Blue teddy
Green camel
Magenta book
Homework

9. Using filters Red Filter
Filters can be used to “block” out different colours of light:
Red Filter
Magenta Filter

10. Investigating filters
Colour of filter
Colours that could be “seen”
Red
Green
Blue
Cyan
Magenta
Yellow