How is Dust Useful to Us?
Most people think that dust is very harmful to us. But this is not true. Dust is, in fact, very useful, and therefore, it is essential to know what dust is and how it is formed.
Every solid substance is composed of very small particles. For example, if we go on breaking a brick or a stone into small pieces, it will turn into small particles. The air then carries dust particles from one place to another.
There are different ways by which dust is formed. When solid substance breaks, dust is formed. Smoke generated by the burning of coal, wood, petrol, etc. also produces dust. Dust particles also come from dead plants, sea salt, desert, volcanic sand, etc. The particles of the earth’s surface also fly in the air in the form of dust.
The biggest use of the dust particles is that they help in the formation of the rains. The water vapors in the clouds condense on the dust particles in the form of water drops. These drops fall on the earth as rain. Likewise, mist, fog, etc. are also formed due to the presence of dust particles.
4. What is every solid substance made of? It is made of . . .
a. Very small particles
b. Small pieces of matters
c. Scattered dust particles
d. Dust particles mixed with air
e. The particles of the earth’s surface
6. How can dust move from one place to another?
a. Smoke carries it
b. Smoke generates it
c. It carries the air
d. It goes on breaking
e. The air carries it
7. Which of the following sentence is true?
a. Dust particles are the most useful
b. The presence of dust particles can delay the rain
c. Raindrops do not contain dust particles
d. Dust particles help the formation of the rain
e. Dust particles are formed as soon as the sun sets
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