Light can be reflected , absorbed or transmitted by objects

1. Light can be reflected, absorbed or transmitted by objects Section 4.2 Lesson 3

2. Laser Properties of Light • Light travels in straight lines: To show the direction in which it travels we use an arrow, called a ray.

3. Light travels VERY FAST – around 300,000 kilometres per second. At this speed it can go around the world 8 times in one second!

4. Thunder and lightning start at the same time, but we will see the lightning first. Light travels much faster than sound. For example: 2) When a starting pistol is fired we see the smoke first and then hear the bang.

5. We see things because they reflect light into our eyes:

6. Absorption • White paper looks white because it reflects light • Black print on white paper looks black because it does not reflect any light • Instead black absorbs all the light energy and coverts it to heat What colour of clothes do you wear on a hot day? Why? What about on a cold day? Why?

7. glass Transmission • Transmission describes how different materials allow different amounts of light to pass through them. • For example – how does light pass through glass? It passes through completely because the glass is transparent

8. Wax paper Transmission • If only some of the light travels through the material but some is scattered or reflected then the material is translucent

9. Brick wall Transmission • If none of the light travels through the material then it is opaque Some light will also be reflected – that’s why we see opaque objects!

10. Shadows are places where light is absorbed by objects that are opaque Shadows

11. Notes • Complete the following handout: • 4.2 Light can be reflected, absorbed or transmitted by objects • When this lesson has been completed work on Lesson 4 – Section 4.2 Objects can absorb some colours and reflect or transmit others.

12. Vocabulary Journal • Add these terms and definitions: • reflection • absorption • transmission • transparent • translucent • opaque