1. 8K Light
8K Light
Travelling light
Bending and reflecting
Colours

2. 8K Light
Travelling light

3. 8K Light shifts
Make up a commentary to describe what’s happening. Use the words ‘straight’, ‘angle of incidence’ and ‘angle of reflection’.

4. How long does light take to reach us from...
8K Light shifts
How long does light take to reach us from...
1 the Sun
2 Pluto
3 the Moon
4 the nearest star other than the Sun
5 a computer screen on your desk
D 8.5 minutes
C 10 hours
B 1.3 seconds
E 4 years
A almost instantly
A almost instantly
B 1.3 seconds
C 10 hours
D 8.5 minutes
E 4 years

5. Match each word to a definition.
8K Light words and heavy meanings
Match each word to a definition.
1 transparent
2 opaque
3 translucent
4 absorbs
5 emits
6 reflects
B light can pass through
E blocks light, creates a shadow
A light passes through but it is scattered so you cannot see clear images through it
F ‘soaks up’ light
C gives out light
D light bounces off
A light passes through but it is scattered so you cannot see clear images through it
B light can pass through
C gives out light
D light bounces off
E blocks light, creates a shadow
F ‘soaks up’ light

6. Light travels in straight lines at very high speed.
8K Light carries energy
Light carries energy.
Light travels in straight lines at very high speed.
How fast?
km per second!
The amount of energy depends on the brightness and the colour of the light.
Blue light carries more energy than red light.

7. 1. The Moon is a light source. 2. The Sun is a light source.
8K And so the light dawns...
True or false?
1. The Moon is a light source.
2. The Sun is a light source.
3. Light sometimes travels in curved lines.
4. Luminous objects radiate energy as light.
5. Sound travels faster than light.
FALSE
TRUE

8. Bending and reflecting
8K Light
Bending and reflecting

9. Light travels in straight lines.
8K Light paths
Light travels in straight lines.
When light passes from one medium to another it may change direction...
…but it still travels in straight lines.
This change in direction is called refraction.

10. What would happen if the light ray hit the glass block at an angle?
8K Light hits you – straight on
What would happen if the light ray hit the glass block at an angle?

11. 8K Light hits you – at an angle
1. Light hits the glass block.
2. This side of the ray reaches the block first and is slowed down.
3. The whole beam bends round.

12. What happens when the light beam leaves the block?
8K Light passes out – at an angle
What happens when the light beam leaves the block?
4. This side of the ray reaches the outside first and speeds away through the air. The beam bends round again.

13. 1. Which of the following is NOT true about light.
8K Light quiz
1. Which of the following is NOT true about light.
a) Light travels in straight lines.
b) Light moves more quickly than sound.
c) Red light moves more quickly than blue light of the same brightness.
2. The glass in a typical window is...
a) opaque
b) translucent
c) transparent.

14. 4. The Moon looks light because... a) it reflects light from the Sun
8K Light quiz
3. A ray of light changes direction when it leaves a glass block. We call this...
a) refraction
b) reflection
c) resignation.
4. The Moon looks light because...
a) it reflects light from the Sun
b) it glows with its own light
c) it gives out cosmic rays.

15. a) light from the stars goes into our eyes
8K Light quiz
5. We see stars when...
a) light from the stars goes into our eyes
b) light travels from our eyes to the stars
c) the Sun’s light is reflected by the stars.
6. John has a glove on his left hand. When he looks in a mirror the glove will look like...
a) it is on his right hand
b) it is on his left hand
c) it has changed into a mitten.

16. 8K Light
Colours

17. Blue light bends the most and red light bends the least.
8K Experimenting with coloured lights
Glass makes light bend – but it doesn’t bend every colour the same amount.
Blue light bends the most and red light bends the least.
Green light is somewhere in the middle.
How much does it bend white light?

18. White light gives a very surprising result.
8K Bending white light
White light gives a very surprising result.
The glass prism bends the light – and shows a complete rainbow of colours.
This tells us that white light is really a mixture of different colours.
The rainbow of colours is called a spectrum.

19. 8K Putting it back together

20. What happens if we add red and green light?
8K Mixing with light
What happens if we add red and green light?
What happens if we add red and blue light?
How do you make white light?

21. A green filter will absorb every colour of light except for green.
8K Filtering light
Coloured filters absorb light. Different coloured filters absorb different colours.
A green filter will absorb every colour of light except for green.

22. What colour would a red filter let through?
8K Filtering light
What colour would a red filter let through?
What filter is in this box?

23. 8K Reflecting light
Many objects reflect light – that is how we see them. Coloured objects only reflect some colours of light.
A yellow object reflects red and green light – remember yellow light can be made by adding red and green light.

24. 1. White light is made up of 10 colours.
8K Rainbow colours
True or false?
1. White light is made up of 10 colours.
2. Violet light is refracted more than any other colour of visible light in the spectrum.
3. A spectrum is a spread of colours.
4. Prisms put colour into light.
5. Indigo is a dark pink colour.
FALSE
TRUE