2. How does
light travel
through
air?
water?
How do
you think
light
travels
through
oil?
3. Experiment
1. Draw three glasses of water in your copy,
one empty, one filled with water and one
filled with oil.
2. Put a pencil in your glass while it is empty
and draw what you see when looking
straight on.
3. Put water in your glass and look again.
Draw what the pencil looks like now.
4. Add oil to the top of the water and draw
how the pencil now looks.
5. Look at
how
light
passing
through
water
makes
the
pencil
look like
it’s
bent!
6. A glass with water and oil
Light bends
more
when
passing
through
oil than it
does
passing
through
water!
7.
8. 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:
The colours in the white all
bend in different directions
and break up so we can see
them easier!
9. The colours of the rainbow:
Red
Orange
Yellow
Green
Blue
Indigo
Violet
10. Seeing colour
The colour an object appears depends on the colours
of light it reflects.
For example, a red book only reflects red light:
White
light
Only red light
is reflected
11. 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
12. When mixing paint colours we mix blue and
red and make purple, yellow and red make
orange and yellow and blue make green.
BUT!!!
When mixing coloured light, we
get different colours
altogether!!
13. Experiment Time!
Attach one colour to the light. Then shine
your new ‘coloured bulb’ through a coloured
filter and see what colour you make when
you mix the colours!
???
14. What do you think happens when
you mix all the colours
together?
15. 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 all
three makes
white again
Adding red
and green
makes yellow
