Dust is usually perceived by us like dirt but in the wrong place. We definitely know all the injurious or harmful effects it produces, but they are also largely due to our own dealings with nature. Although we can thus minimize the dangers and the inconveniences arising from the grosser forms of dust, we cannot wholly abolish it. Indeed, it is fortunate that we cannot do so, since it has now been discovered that due to the presence of dust, we owe much of the beauty, and perhaps even the very habitability, of the earth we live upon. Importance of dust particles has always been neglected but they are very important and useful.
Few of the fairy tales of science are more marvelous than these recent discoveries as to the varied effects and important uses of dust in the economy of nature. At one point, we must all have thought how good it would be to have no dust around. So, we all do wonder where does it come from anyway. It is a general belief that dust is very harmful to us. Interestingly, this is only one side of the picture. Yes, dust is annoying but it also is very useful to us. Before we go through the uses of dust, it is essential to know what is dust and how it is formed?
How Does Dust Form? – What Is Dust Made Up Of?
Every solid substance is composed of very small particles. When these small particles of matter are scattered, they become dust particles. For example, 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.
Dust Are Useful – Its Applications In Nature
Dust may seem useless but they are necessary for many things that happen in nature.
1. Dust Helps To Have Gentle Rainfall
Due to the presence of dust in the higher atmosphere, we owe the formation of mists, clouds, and gentle beneficial rains, instead of waterspouts and destructive torrents. The biggest utility of dust particles is that they help in the formation of rains. The water vapor 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.
This theory was initially discovered in France by Coulier and Mascart, but more thoroughly worked out by Mr. John Aitken in 1880. Their number of experiments showed that the mere cooling of vapor in the air will not condense it into mist clouds or rain unless particles of solid matter are present to form nuclei upon which condensation can begin.
The density of the cloud is proportionate to the number of particles present. Hence the fact that the steam issuing from the safety-valve or the chimney of a locomotive forms a dense white cloud shows that the air is really full of dust particles, most of which are microscopic but none the less serving as centers of condensation for the vapor. Hence, if there were no dust in the air, escaping steam would remain invisible; there would be no clouds in the sky; and the vapor in the atmosphere, constantly accumulating through evaporation from seas and oceans and from the earth’s surface, would have to find some other means of returning to its source.
2. Scattering Sun-Rays
Everyone has seen the floating dust in a sunbeam when sunshine enters a partially darkened room. However, it is not generally known that if there was absolutely no dust in the air the path of the sunbeam would be totally black and invisible.
The blue color of the sky is due to Rayleigh Scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air. However, much of the shorter wavelength light is absorbed by the dust and gas molecules. The absorbed blue light is then radiated in different directions and it gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.
As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions and less blue light reaches your eyes. Thus, the color of the sky near the horizon appears paler or white. Also, 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 sunset. The appearance of red color sunrise and the sunset due to dust particles and water vapor. The beautiful rays of the sun seen in the twilight are also due to these dust particles.
3. Makes The Soil Better For Agriculture – Due To Loess
Loess is a clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. They are very fine-grained sediment with just some traces of larger sand grains that form many hundreds of feet thick, very homogenous, deposits, covering almost ten percent of Earth’s surface.
The soil is among the most fertile in the world, principally because the abundance of silt particles ensures a good supply of plant-available water, good soil aeration, extensive penetration by plant roots, and easy cultivation and seedbed production. Also, micaceous minerals in the silt and clay fractions provide an adequate supply of potassium for most crops, and the large amounts of total nitrogen in chernozems can maintain moderate yields of cereals without fertilizer additions.
In regions of thin but fairly extensive loess deposits, such as UK and parts of USA, loess probably plays an important role in maintaining yields of arable crops and needs special measures to protect it from the increasing erosion noted in recent decades. As loess often lacks any particular sedimentary features, needed to reconstruct its deposition, geologist struggled for a long time to understand how loess deposits formed. Thus, there are many theories behind its formations.
We find that the much-abused and all-pervading dust is an essential portion of the economy of nature. Dust gives us much of the beauty of natural scenery as due to varying atmospheric effects of the sky, and cloud, and sunset tints making life more enjoyable. Moreover, it appears to be absolutely necessary for our existence upon the earth, perhaps even for the very development of terrestrial and habitat. Hence, we see that dust particles which are regarded as absolutely harmful by people are in reality very useful. They are significant for the world to function the way how it is functioning today.