How is dust useful to us?

2] HOW IS DUST USEFUL TO US?

Many of us believe that dust is harmful to

us but this is only one side of the picture.Dust is also useful to us. But before we

go through the uses of dust, let us find out

what dust is, and how it is formed. Every solid

substance is composed of very small particles.

When a substance disintegrates, its small

particles scatter and they form dust particles.For example, if we break a brick into

small pieces, it produces small particles in

the form of dust. There are a number of

ways by which dust is formed. Smokegenerated by the burning of coal, wood,petrol, etc. also produces dust. 

Dead plant

and animal matter, sea salt, desert sand,

volcanic ash, etc. also produce dust particles.

These dust particles mix with air, which are

carried from one place to another.Thus, particles from the Earth's surface

fly in the air in the form of dust. Did you

know that dust helps in rainfall? The water

vapour in the clouds condenses on dust

particles in the form of waterdrops.

These drops fall to the Earth as rain.

The absence of dust particles can hinder

rainfall. Likewise, mist, fog, etc. are also

formed due to the presence of dust particles

in the atmosphere.The dust particles present in theatmosphere scatter sunlight in all possible

directions. It is due to this phenomenon that

there is light even after sunset for an hour or

two. The lovely red colour seen at sunrise and

sunset is also the result of the dust particles

and water vapour present in air.We are able to witness the breathtaking

hues of the Sun seen during twilight owing

to the scattering of light by dust. Thus the

dust particles, which are usually considered

harmful by many, are actually indispensable .