Visible Light Spectrum

Aim:

To split the white light into its constituent visible spectral colours through the following experiment.

Materials required:

1.      A sized piece of white paper or a white cardboard.

2.      A mirror small in size.

3.      A shallow dish/pan large enough to hold the mirror horizontally

4.      Water and an outdoor sunny place.

Procedure:

1.      Fill the dish with water.

2.      Place it on any flat surface like table or floor, directly under sunlight.

3.      Now submerge the mirror in the water completely with the shiny surface facing sunlight.

4.      Hold the paper above it in and then accordingly adjust the paper as well as the mirror till the reflection of sunlight shines on the white paper.

5.      Observe the resulting spectrum.

Scientific explanation:

White light is a combination of light of different colours. So when light is made to pass from air to water the speed and direction of its constituent colours are affected. This is called refraction. This results in bending of light of different colours and it depends on the speed with which it travels through water. All the colours have the same speed in air but when it comes to water Red light travels the fastest and therefore bends the least. On the other hand, Violet light bends the most as it slows the most in water. Thus this phenomenon is called refraction of white light which results in a visible colourful spectrum.