It is a general belief that dust is very harmful to us. But this is only one side of the picture. Dust also is very useful to us. Before we go through the uses of dust, it is essential to know what dust is and how it is formed.
Every solid substance is composed of very small particles. When these small particles of matter are scattered, they become dust particles. For example, if we break a brick or a stone into small pieces, it will turn into small particles of dust. There are different ways by which dust is formed. When solids break, dust is formed. Smoke generated by the burning of coal, wood, petrol etc, also produces dust. Dust particles also come from dead plant and animal matter, sea salt, desert, volcanic ash etc. These particles get mixed with air and are called dust particles. Air carries dust particles from one place to another. The particles of the earth’s surface also fly in the air in the form of dust.
The biggest utility of dust particles is that they help in the formation of rains. The water-vapour in the clouds condenses on dust particles in the form of water-drops. These drops fall on to the earth as rains. The absence of dust particles can delay the rain. Likewise, mist, fog etc. are also formed due to the presence of dust particles in the atmosphere.
The dust particles present in the atmosphere scatter sun-rays in all directions. Due to this scattering, there is not complete darkness for one to two hours even after the sun set. The appearance of red colour at the sunrise and the sunset is due to dust particles and water vapour. The beautiful rays of the sun seen in the twilight are also due to these dust particles. Thus we see that dust particles which are regarded as absolutely harmful by people are in reality very useful.
