Making Rainbows

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3 Methods for splitting light to make Rainbows - Pictures Attached


Drinking Glasses
Small Mirror
Torch (With an adjustable beam is best)
An Old CD (Preferably not too scratched!)
White Paper/Card
Sticky Tape


Method 1: Using a Mirror
a. Place a small mirror inside a full glass of water.
b. Make sure the room is dark, and has white walls.
c. Shine the torch into the water, moving it around until a rainbow can be seen.

Method 2: Using a CD
a. Take a CD. Wipe it to make sure it is not dusty so it will look better.
b. Place it on a flat surface, label side down, under a light or in front of a window.
c. Look at the CD, and see the rainbow.
d. Hold the CD in between your fingers and move to see how the colours move.

Method 3: Using a Torch
a. Find a piece of white paper. Fold it in half, and cut a little triangle with a pair of scissors.
b. Fill a glass with water. A fishbowl, or other clear container will also work well.
c. Tape a torch onto the piece of paper, so that the light from the torch shines through the small triangle.
d. Hold the paper up using the torch.
e. Aim the beam of light from the torch directly at the glass of water.
f. (Bam!) A rainbow has appeared.

The Science:
Sunlight isn't just white – it’s actually made of a mixture of different colours. As light travels through water or glass, it changes speed, which makes it bend.
Light travels in waves. Different colours in the light have different wavelengths, and bend (refract) by different amounts. This makes the different colours spread out and separate from each other (disperse), forming a spectrum or rainbow.


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