1. Colour & Filters
D. Crowley, 2008

2. Colour & Filters
To know how coloured filters work, and to be able to predict how these will affect the appearance of an object

3. Light Key Words Solve the following anagrams of light key terms…
Suonmiul
Nno-minluous
Depisrdes
Detcfrare
Ferletced
Eencidnci
Glane
Msurtcpe
Rooluc
Luminous
Non-luminous
Dispersed
Refracted
Reflected
Incidence
Angle
Spectrum
Colour

4. Colour Look at the following colours – why do we seem them?
Object
Filter
Look at the following colours – why do we seem them?
Coloured objects reflect some colours and absorb others
Red absorbs all colours, except red which it reflects
Green absorbs all colours, except green which it reflects
Blue absorbs all colours, except blue which it reflects
Black absorbs all light, reflecting none…
White reflects all light, absorbing none…

5. Colour Now look at the following colours through a filter…
Object
Filter
Now look at the following colours through a filter…
Filters let certain colours of light pass through, but absorb all other colours
Using the different filters look at the colours on the board / around the room and try and work out what the filter is doing – i.e. what is a blue filter doing? What about a red filter etc…

6. Colours A red filter absorbs all colours… …apart from red light
A blue filter absorbs all colours…
…apart from blue light
A green filter absorbs all colours...
…apart from green light

7. Colours A magenta filter absorbs all colours…
…apart from red and blue light
A cyan filter absorbs all colours…
…apart from green and blue light
A yellow filter absorbs all colours...
…apart from red and green light

8. Light
Filters can make objects appear different colours than they actually are
This is because they only let a certain type of light through (e.g. red filter only lets red light through)
Looking through a red filter can therefore be described as looking at something in red light
Red light shines on the ball
The red ball reflects the red light, appearing red

9. Red Ball
What does a red ball appear like in different light, e.g. in green, blue and magenta light?
In green light
Green light shines on the ball
The red ball absorbs the green light, so no light is reflected, and the ball appears black

10. Red Ball
What does a red ball appear like in different light, e.g. in green, blue and magenta light?
In blue light
Blue light shines on the ball
The red ball absorbs the blue light, so no light is reflected, and the ball appears black

11. Red Ball
What does a red ball appear like in different light, e.g. in green, blue and magenta light?
In magenta light (mix of red and blue)
Magenta light shines on the ball
The red ball absorbs the blue light and reflects the red light, appearing red

12. Filter

13. Light Questions

14. Light Answers Light cannot travel through a stone
Luminous source - lamp
Opaque object - desk, cup, book etc…
Transparent object - glass, window etc…

15. Light Answers
Box B
Normal
Light is dispersed in all directions