- The earth's atmosphere is a mixture of many minute particles such as smoke, water droplets, dust etc. When a beam of light strikes these fine particles, the path taken by that beam becomes visible. Light gets reflected continuously by these particles and then reaches us.
- This phenomenon of scattering of light by particles is the Tyndall effect.
- Tyndall effects explain why we see the sky as blue, forests as green and so on.
Why does the Sky appear clear blue?
- The air molecules and other fine particles have sizes smaller than the wavelength of visible light.
- Such particles scatter light of shorter wavelengths ie blue more effectively than longer wavelengths( red)
- When sunlight passes through the atmosphere, the blue end of the spectrum is scattered more.
- This enters our eyes and hence we see the sky as blue