Sunlight or electric light is called 'white light', because it appears to be colourless. The reality is that 'white light' is made up of a mixture of different colours called a 'spectrum', when broken up. These colours can be observed when white light passes through a transparent substance, such as water or glass. A 'spectrum' consists of the seven colours of the rainbow: red, orange, yellow, green, blue and violet – as well as two other invisible colours called: ultra-violet and infra-red. Isaac Newton used a 'prism' to split up white light into different colours. In this science experiment we will use water and a mirror to do the same.
Materials:
LARGE, DEEP TRAY
WHITE CARDBOARD
MIRROR
TAP WATER
Procedure:
1. Fill a large, deep tray with some water and place it up against a wall outside on a sunny day. Position the tray so that the sunlight falls onto the mirror.
2. Rest a flat mirror upright against the inside, so that it is supported by the wall if necessary.
3. Hold a sheet of white cardboard in front of the mirror and move it around until a rainbow of colours appears on it! You might have to adjust the position of the mirror and the cardboard several times to get the best results.
