1. from bonfires to lasers
LIGHT !
from bonfires to lasers

2. Sources of light
A bonfire
Hot objects give out light.

3. The Sun
Sunset in Venice

4. Stars
Stars and galaxies give out light.
Picture: Liverpool Telescope

5. Lightning

6. A worm living in dark caves sends out light from its tail.
Liquid droplets form a string of shining beads to attract insects.
tail of worm

7. Some cold things give out light:
some fungi
glow worms
light sticks
LEDs
‘glow-in-the-dark’ stickers

8. How do we see light sources?
Light travels from a source to our eyes.
We can see sources in a dark room.

9. Can we see in the dark? If there is no light Let’s try a test–
we cannot see anything!
Let’s try a test–
Put a few small objects into the black bag-----

10. How do we see things that are not sources of light?
Light bounces off
and some reaches our eyes.

11. On the look out !
How do you know that the baby squirrel watches as it feeds?

12. Reflection When light bounces off something We can try this with
we say the light is reflected.
We can try this with
rough surfaces
and shiny surfaces.

14. Shiny surfaces wall mirror
Light is reflected as a beam and can be seen on the wall.

15. Move the mirror
wall
The light reaches a different place on the wall.

16. Look in a mirror
Light is reflected.
You can see a reflection.

17. Change the direction of the light beam
Light is still reflected.
You see a reflection
- in a different
direction.

18. Multiple reflections
The lamp hangs between two large mirrors on opposite walls.
The reflection in the first mirror is reflected in the second mirror, which is reflected again in the first mirror - - -

19. Now for some games !

20. Colour

21. Sunlight shining on CDs
Where do the colours come from?

22. Rainbow
red
orange
yellow
green
blue
indigo
violet

23. Colours
White light is made up of lots of colours

24. Colours from white light
Look at a lamp through the grating.
You will see colours.

25. red

27. blue

28. Adding colours with light
This is different to adding paints

29. Red + Blue
 magenta

30. Blue + Green
 cyan

31. Green + Red
 yellow

33. yellow

34. magenta

35. cyan

36. Fairy lights

37. Uses Lasers- produce very bright beams of light. CDs use laser light
The atoms all give out their light together
CDs use laser light
and reflection-

38. CDs The surface has tiny pits and smooth bits
spiral
The surface has tiny pits and smooth bits
in a spiral pattern
the pits scatter light from a laser
the smooth bits reflect the light
so a coded message is read.

39. Laser show
Physics is in everything