Why do fine particles scatter light

Air molecules, like oxygen and nitrogen for example, are small in size and thus more effective at scattering shorter wavelengths of light blue and violet. The selective scattering by air molecules is responsible for producing our blue skies on a clear sunny day. Another type of scattering called Mie Scattering is responsible for the white appearance of clouds.

What do you observe? You will find fine microscopic sulphur particles precipitating in about 2 to 3 minutes. As the sulphur particles begin to form, you can observe the blue light from the three sides of the glass tank. This is due to scattering of short wavelengths by minute colloidal sulphur particles.

Observe the colour of the transmitted light from the fourth side of the glass tank facing the circular hole. It is interesting to observe at first the orange-red colour and then bright crimson red colour on the screen. This activity demonstrates the scattering of light that helps you to understand the bluish colour of the sky and the reddish appearance of the Sun at the sunrise or the sunset.

However, light from the Sun overhead would travel a relatively shorter distance. At noon, the Sun appears white as only a little of the blue and violet colours are scattered. Near the horizon, most of the blue light and shorter wavelengths are scattered away by the particles. Therefore, the light that reaches our eyes is of longer wavelengths. This gives rise to the reddish appearance of the Sun. Online Class Content Faculty. Scattering Of Light - Tyndall Effect Scattering Of Light The interplay of light with objects around us gives rise to several spectacular phenomena in nature.

At the time of sunrise and sunset when the sun is near the horizon, the sunlight has to travel the greatest distance through the atmosphere to reach us. During this long journey of sunlight, most of the shorter wavelength blue-colour and shorter wavelengths present in it is scattered out. Therefore, the light that reaches us is of longer wavelengths. Hence the sun appears red. Related Posts The human eye and its construction Power of accomodation Defects of vision : causes and correction Refraction of Light Dispersion and spectrum of light Atmospheric refraction.

Start your learning Journey! In the west the sky is brightest near the horizon left , in the east it is darkest there due to the earth's shadow.

Above the shadow zone there is a slight pink reflection of the setting sun's red light. Left: Feather of an Eurasian jay. Image width 4 cm. Right: enlarged detail. An average has been taken over systems. The results are in agreement with the experimental findings of Prum et al. Green colour is achieved by adding a transparent top layer of yellow cells. Their pigment mostly a carotenoid acts like a filter and quenches the short waves.

This is modeled in the adjacent figure. The blue line is the scattered light without the yellow layer, the same as in the right image above. The thin yellow line is the transmittance of a yellow filter slightly idealized , and the green line is obtained by applying the filter to the spectral distribution given by the blue line. The colour without and with the yellow layer is also shown. Autumn leaves and blue, cloudless sky. Automatic white balance.

Immediate comparison looking alternatingly out of the window and at the screen attests optimal reproduction of the colours. The same autumn leaves one day later with overcast sky and drizzle. Here now, the right picture is closer to the visual impression. This could hardly have been decided without immediate comparison. Dietrich Zawischa Contact Deutsche Version.

In the air, part of the sunlight is scattered. The small particles molecules, tiny water droplets and dust particles scatter photons the more, the shorter their wavelength is. Therefore, in the scattered light, the short wavelengths predominate, the sky appears blue, while direct sunlight is somewhat yellowish, or even reddish when the sun is very low.

The colours of sunrise and sunset sometimes even show themselves on the moon.