Light Filters
What is a Light Filter?
A light filter is a transparent material, that
contains a pigment, that allows only specific
colours of light to pass through it.
 For example, a red light filter allows red light
to pass through it while absorbing all other
colours of light.


A pigment is a colouring agent that absorbs
certain colours of light and reflects other
colours of light.
Light Filters in Action


The filter on top
is red so it
blocks every
colour except
for red – which
passes through
so we see red
light.
The bottom filter
is a blue filter so
only blue light
gets through.
Light Filters in Action
http://www.youtube.com/watch?v=zvfdOiBDgXA
Wait a Minute!!!...



The previous video showed red light passing through a
red filter…that seems OK…
Then it showed the red light getting blocked by the
blue filter…that seems OK too…
BUT, what happens when the red light is still able to
pass through the yellow filter? Shouldn’t the yellow
filter block the red light since they are two different
colours? How is that possible?

You have to remember that yellow light is made up of both
red and green light mixed together. Each filter only lets its
own colour light through and yellow treats red and green as
its own light because they are the components of yellow
light.
Predict the Following!
THE END