- Sunlight is made up of a mixture of red, orange, yellow, green, blue, violet and indigo. These colours are the same as that of a rainbow. A prism can be used to see all the colours of the sun. When light passes through a prism, it bends. Each colour can be seen at a different angle. Violet bends the most, while red bends the least.
WHY DON’T WE USUALLY SEE SUNLIGHT AS SEVEN COLOURS?
- We assume sunlight to be white in colour. This is because when all the colours are mixed up, it looks white.
- Light refracts, or bends, when it passes from one medium to another. Every colour of sunlight has a different wavelength. When sunlight passes through a prism, the light separates into its constituent colours with the shorter wavelengths refracting at greater angles than the longer wavelengths. Since violet light has the shortest wavelength, it bends the most; red light has the longest wavelength, so it bends the least.
THINGS TO DO
- Cut out a circle from a piece of card and paint it the colours of the rainbow: red, orange, yellow, green, blue, indigo and violet. Stick a pencil through the middle of the card and spin it. It looks white.
- With the help of a prism, direct light through it and see for yourself if you see all the colours of the sun.
- Watch the experiment “Invisible Glass Trick” on www.mocomi.com to understand ‘refraction of light’ better.