Whenever after a downpour you look at the sky, you can see a seven-coloured arc in the sky. It is the rainbow. Rainbows are so beautiful to look at. With this project experiment, you can make your own rainbow.
1) Glass of water
2) White Paper
1) Fill a glass full with water.
2) Place the glass near a window through which sunlight is coming in. Or you can also place it on a table outside where there is enough of sunlight.
3) Carefully put the glass on the edge of the table so that it is half on and half off, without tipping over!
4) Make sure the sun is shining through the water.
5) Position the white paper on the floor so that the shadow of the glass falls on it. You will notice that a rainbow shows on the paper.
Do you understand how this happens? A clear glass has two surfaces through which the light passes - the inner and the outer surface. Light contains a spectrum of colours. Narrowly said, the spectrum consists of seven colours - violet, indigo, blue, green, yellow, orange and red - commonly known and remembered as VIBGYOR. When the light passes through the inner to the outer surface of the glass, light waves of different frequencies (colors) bend different amounts. In most cases, we cannot see them all. But through prisms (optical device having a triangular shape and made of glass or quartz) we can see all of the colors.