1. Learning Outcomes Today you will:
Explain how the colours of objects depend on the colours in light which they absorb and reflect
Explain why objects appear to be different colours in different coloured lights in terms of the different wavelengths

2. Memorise these. You have 30 seconds. GO!
Today you will:
Explain how the colours of objects depend on the colours in light which they absorb and reflect
Explain why objects appear to be different colours in different coloured lights in terms of the different wavelengths

3. Name two words highlighted in orange.

4. Name two words highlighted in red.
Today you will:
Explain how the colours of objects depend on the colours in light which they absorb and reflect
Explain why objects appear to be different colours in different coloured lights in terms of the different wavelengths

5. Lesson Objective
Be able to use the words wavelength, absorb and reflect to explain why we see objects as different colours

6. Q. When is a red ball not a red ball?
10.5b Can colours change?
Q. When is a red ball not a red ball?

7. A. When you see it under green light
10.5b Can colours change?
A. When you see it under green light

8. Mixing coloured lights
10.5b Colours
Mixing coloured lights
Red, green and blue are called primary colours. All other colours can be made by combining these in various ways.
Magenta, cyan and yellow are secondary colours. They are made by combining two primary colours.

9. Why does my apple look red?
10.5b Colours
The skin of a red apple contains a pigment that reflects red light but absorbs all other colours of the spectrum shining on it.

10. 10.5b Colours
Black…
Black objects absorb nearly all the light energy shining on them.
Black objects also absorb heat radiation (infrared) so keep you warmer.

11. …and white
10.5b Colours
White objects reflect nearly all the light energy shining on them.
White objects also reflect infrared so help to keep you cool in hot weather.

12. Progress check… 10.5b Colours
Ed’s T-shirt is yellow because it r________ yellow light, but _______ all other colours of the spectrum shining on it.
Polly’s T- shirt is red because _________________________________ _________________________________ ________________________
Black objects a_____ nearly all the light energy shining on them.
White objects r_______ nearly all the _____ _______ shining on them.

13. Peer Mark: /7
10.5b Colours
Ed’s T-shirt is yellow because it reflects yellow light, but absorbs all other colours of the spectrum shining on it.
Polly’s T- shirt is red because it reflects red light, but absorbs all other colours of the spectrum shining on it.
Black objects absorbs nearly all the light energy shining on them.
White objects reflect nearly all the light energy shining on them.

14. Reflection and Absorption
10.5b Why colours change
An apple looks red in normal (white) light because it reflects red light and absorbs all the other light rays shining on it.

15. Wavelengths 10.5b Why colours change
Each colour in the spectrum has a different wavelength. This is why they behave differently when the waves pass through a glass prism or strike a coloured object.

16. The Spectrum of Light 10.5b Why colours change
Remember, white light is made up of all the colours of the spectrum.
Can you remember them?

17. Green light 10.5b Why colours change
If the red apple is seen in green light it looks black because the pigment in its skin absorbs all the waves, or colours, except red.
There are no red waves in green light so the apple does not reflect any light.

18. Progress Questions 10.5b Why colours change
Answer these questions on your whiteboards:
What colour would Ed’s T-shirt appear
In red light?
In yellow light?
In blue light?

19. How confident are you?
Turn your planners to either red, yellow or green, depending on how confident you feel our lesson objective.
Be able to use the words wavelength, absorb and reflect to explain why we see objects as different colours

20. If you finish, attempt the extension questions below.
My worksheet monitors will give out the assessed worksheets. My whiteboard monitors will collect the whiteboards, pens and rubbers. I will be giving your answers a mark which your parents will see at parents evening. You have 20 minutes to complete your worksheet.
If you finish, attempt the extension questions below.
10.5b Why colours change
Extension Questions:

21. Your homework is to revise!
10.5b Why colours change
HOMEWORK: You have a test on Tuesday next week. This test will cover everything we have done on the topic of Light over the past two weeks and before Easter.
Your homework is to revise!

22. How confident are you?
Turn your planners to either red, yellow or green, depending on how confident you feel our lesson objective.
Be able to use the words wavelength, absorb and reflect to explain why we see objects as different colours

23. Once you have done this, and handed your answers to me, you can go.
10.5b Why colours change
To finish:
List 10 things you have learned about light, and what you have enjoyed learning the most.
Once you have done this, and handed your answers to me, you can go.
Don’t forget to revise!