Question

When light travels through mediums of different densities, it bends from its normal direction of motion. Also, the earth's atmosphere has layers of varying density. Using the above facts, explain why stars twinkle?

Answer 1

1. The hot air has less density than cold air.
2. The medium whose density is less is called a rarer medium.
3. The medium whose density is more is called a denser medium.
4. When light travels through mediums of different densities its speed changes.
5. Due to changes in speed, light suffers the phenomena of refraction.
6. When a ray of light travels from one medium to another it bends towards the normal or away from the normal, this phenomenon is called refraction of light.
7. The light coming from the stars enters the earth's atmosphere.
8. Due to the varying densities of atmospheric air, it suffers a lot of refraction.
9. As a result, when light reaches our eyes it looks like that star is twinkling.