Rainbows and Prisms WALT Describe the parts of
Rainbows and Prisms • WALT: Describe the parts of white light and how prisms and rainbows work • I must be able to state the 7 colours of white light • I should be able to explain how a prism or rainbow shows us these
Starter: In pairs – No 1 s explain reflection No 2’s explain refraction
Light from the sun is called white light. White light is made up of the seven colours of the rainbow. Red, orange, yellow, green, blue, indigo and violet.
How we see colour We only see the colours that are reflected off an object. The other colour parts of light are absorbed. Example: A red object reflects red light into our eyes but all the other colours are absorbed by the object.
Why do you think many Mediterranean countries have white coloured houses?
How a prism and a rainbow works • White light enters the prism or water droplet and is refracted • The prism or water droplet splits white light into its different colours which spread out because they are refracted
Primary and secondary Colours There are three Primary Colours. These are RED, BLUE, GREEN. We can add these colour lights to produce the secondary colours. ALL VISIBLE LIGHT IS ONLY MADE OF BLUE, GREEN AND RED. The secondary colours are YELLOW, MAGENTA, CYAN.
Turn to page 416 of the red books Let’s read through the first paragraph together. Now you are going to make a Newton’s Disc out of card. Colour it in like in the diagram and then spin it around with your pencil. What do you see?
Before digital technology. . how do you think people in submarines could see above the water surface?
This is called a periscope Which angle should the mirrors be at?
When you have finished making your periscope Draw a diagram to show the periscope works – include the angles of reflection Label the angles and normal lines
Plenary • In silence – write down 5 facts you have learnt over the topic of Light • In pairs – discuss and add any facts you don’t have to your list
Plenary • Write a 6 question quiz for your neighbour to answer on the whole topic of Light.
• Since all the visible light we see is just a combination of red, green, and blue light, it can change depending on what you are looking at through the filter. If you have something that looks white and a filter that blocks green light, when you look through the filter it may appear as purplish, a mixture of red and blue. But, if you look at something green, you may get a grayish color, since it is blocking most of the light coming from it.
- Slides: 15