1. Objectives: What is a spectral colour? Why do objects look different colours? Why do lemons look yellow? Write the title, the date and the objectives!

2. Can I have your tests please?

3. Recap Draw on your white boards how you can split white light into a a spectrum using a prism. Show where the red and blue ends of the spectrum are. Write the colours of the rainbow? Which colour has the shortest wavelength? What is white light? What is black?

4. Why does this lemon look yellow?

5. The object looks a specific colour when that colour reflects into our eyes and the other colours are absorbed. Yellow lemons look yellow because the lemon reflects the yellow light and absorbs the other colours.

6. Filters If you put a red filter in front of white light or in front of a spectum, it absorbs the blue and green light. The light looks red because only the red light or the red and orange light goes through the filter.

7. Spectral colours Each of the colours in the spectrum are spectral colours. If you pass a spectral colour through a prism, it will not split up into more colours.

8. Spectral colours Sometimes the light looks red, but is actually a mixture of red, orange and yellow, for example. This red is not a spectral colour.

9. Do the worksheet!

10. Questions 1.What is white light? 2.How can you test which colours are in white light? 3.Why do different colours refract differently? 4.Which colour has the shortest wavelength? 5.Who first examined the spectrum? 6.Why do we have seven colours in a rainbow? 7.In which ways is sound similar to light? 8.What is a spectral colour? 9.How can you test if a colour is a spectral colour? 10.Why does a red chair look red?

11. Answers 1.White light is what we see when all (or most) of the colours appear together. 2.You can test which colours are in white light by passing white light through a prism. 3.Colours refract differently because they have different wavelengths. 4.Blue has the shortest wavelength. 5.Sir Isaac Newton first examined the spectrum. 6.Newton chose seven colours for the rainbow because there are seven notes in an octave. 7.Both sound and light travel in waves. Sound sounds higher or lower to us because different sound waves have different wavelenths. Light looks different because different colours have different wavelengths. 8.A spectral colour is a colour which cannot be split up into more than one colour. (that means it is light which has a certain wavelength.) 9.You can test if a colour is a spectral colour by passing it through a prism. 10.Why does a red chair look red? A red chair looks red because the red light is reflected from it and the other colours are absorbed.

12. Why do objects look different colours? Draw on your white board how we see an object. Now draw what happens when an obect looks red in white light.