Where is there light in this room?

Light is all around us.

Make a new title page:

Light and Sound

How does light travel?

Learning Objectives:

• To understand that light travels from a source.

• To know that light travels at a very high speed, much faster than sound.

Task

1. Draw some lightning then try to explain which comes first, the clap of thunder or the flash of lightning?

2. Why does one come before the other?

3. What happens if you move further away from the storm?

Light travels much faster than sound. For example:

1) Thunder and lightning start at the same time, but we will see the lightning first.

2) When a starting pistol is fired we see the smoke first and then hear the bang.

Light travels VERY FAST – around 300,000 kilometres per second.

At this speed it can go around the world 8 times in one second.

8K Light shifts

1 the Sun

2 Pluto

3 the Moon

4 the nearest star other than the Sun

5 a computer screen on your desk

A almost instantly

B 1.3 seconds

C 10 hours

D 8.5 minutes

E 4 years

How long does light take to reach us from...

D 8.5 minutes

C 10 hours

B 1.3 seconds

E 4 years

A almost instantly

How light travels

• Do Experiment A and B

• Remember the aim is to try and shine light on the board at the end!

• How do you know that light travels in a straight line• Write a conclusion from each of the

experiments that explains this

Investigating how light travels?

1. How can you get the light to shine on the card? What does this tell you about the way light travels?

1. How did you get the light to shine on the white card? What does this tell you about the way light travels?

Investigating how light travels?

Explain what you have seen

• Light travels in straight lines:

Laser

Drawing light waves

• Light travels in straight lines• We can represent a ray of light using a

straight line with an arrow to show the direction of travel

• Draw diagrams of today’s investigations using light rays

Light carries energy and travels as a wave.

Light travels at 300 000 000 m/s or 300 000 km/s (much faster than sound).

Light waves travel in straight lines.

Summary

How does light travel?

Learning Objectives:

• To understand that light travels from a source.

• To know that light travels at a very high speed, much faster than sound.