INTRODUCTION
Atmospheric air and its uses are very essential for our survival on this earth. We are living in an atmospheric ocean. Atmospheric air and its uses are for man-animal both. Atmospheric air and its uses surround the earth’s surface to protect it. It stretches about 10,000 kilometers above the surface of the earth. As per NASA various gases are contained in the atmosphere. Major gases according to volumetric share are:
(1)Nitrogen-78%
(2) Oxygen – 21%
(3) Argon- 0.93 %
(4)Carbon dioxide – 0.04%.
Other gases in the atmosphere are in traces, they are neon, helium, methane, krypton, hydrogen, and water vapor. Our atmosphere is a mixture of the above gases, however, we call it atmospheric air.
ATMOSPHERIC LAYERS OF EARTH
Atmospheric air layers of the earth are 6 in numbers as per the scientific study. The first layer of the atmospheric air is denser, as compared to other layers of the atmosphere. The 6 layers of the atmospheric air are:
(1)TROPOSPHERE
(2)STRATOSPHERE
(3)MESOSPHERE
(4)THERMOSPHERE
(5)IONOSPHERE
(6)EXOSPHERE
TROPOSPHERE
The troposphere is the first layer of the atmospheric air. It begins from the earth’s surface and extends up to 9 miles above the earth’s surface. It is the densest, all-weather activities happen in this region.
STRATOSPHERE
After the troposphere, the layer of the stratosphere begins. It extends up to 31 miles surrounding the earth. The stratosphere is the ozone layer that shields the earth. It protects the earth from the harmful ultraviolet rays of the sun. It absorbs and scatters ultraviolet radiation.
MESOSPHERE
The mesosphere layer of the atmosphere begins above the stratosphere. It extends up to 53 miles above the earth’s surface. Meteors and other objects falling on the earth get burnt in this layer. It is the protection layer to the earth. It protects the falling of heavy objects from space to earth, which is a threat to life on earth.
THERMOSPHERE
The thermosphere is the atmospheric layer that begins above the mesosphere and extends up to 370 miles high. Aurora is seen in this region.
IONOSPHERE
The ionosphere is the layer of the atmosphere that contains electrons and ionized atoms and molecules. It extends up to 600 miles. The ionosphere is variable according to solar conditions. Radio communication is possible due to the ionosphere.
EXOSPHERE
The exosphere is the last layer of the atmosphere. Its limits end at about 6200 miles above the earth’s surface.
ATMOSPHERIC AIR PROPERTIES
(1) Air is compressible
(2) Air is elastic
(3) Air exerts pressure in all directions
(4) Air has a weight
(5) Air is invisible
(6) Air blowing can be felt
(7) Air blows from a cold region to a hot region
Air is compressible:
In the bicycle pump, the pump piston is pushed forward, and the outlet of the pump is kept closed, the air gets compressed in the pump cylinder. When the pump outlet is opened, compressed air is released with a pop.
Air is elastic:
In a bicycle pump when pressure is released on the piston of the pump, compressed air comes to its original position, which indicates the property of elasticity of air.
Air exerts pressure in all direction:
Examples of air pressure exertion in all direction is an inflated balloon, football, vehicle Tyre, and tennis ball.
Air has weight:
The difference in weight of an empty balloon and a balloon filled with air indicates, that air has weight.
ATMOSPHERIC PRESSURE USES
Devices that work on air pressure are:
- Dropping tubes
- Injection syringes
- Pipettes
- Drinking straw
- Preserving jars
- Vacuum cleaners
- Pumps
- Bicycle pump
DROPPING TUBE
In the drop tube when the rubber bulb is pinched vacuum is created and due to atmospheric pressure liquid is sucked into the tube. Again when the rubber bulb is pinched liquid pushed out of the tube dropwise.
INJECTION SYRINGES
When the plunger of the syringe is pulled upward vacuum is created in the syringe and liquid is sucked in the syringe, during the downward push of the plunger liquid is expelled out of the injection.
PIPETTES
In pipettes also the liquid is filled in pipette due to vacuum and atmospheric pressure.
DRINKING STRAW
In a drinking straw vacuum is created by mouth and liquid is sucked in the straw due to atmospheric pressure.
PRESERVING JARS
Lids are placed on the jar when the contents of the jar are hot. As the content of the jar gets cooled, a vacuum is created in the jar, and the lid of the jar holds tightly on the jar due to atmospheric pressure.
PUMPS AND BICYCLE PUMP
Working on pumps a bicycle pump is self-explanatory in the following fig.
COMPRESSED AIR USES
When air is compressed, its working power is increased much fold. Compressed air is used in power tools to operate the equipment. Following are the industries, where compressed air is used:
(1) Aerospace
(2) Automotive
(3) Chemical manufacturing
(4) Electronics
(5) Food and beverage
(6) Glass manufacturing
(7) Medical
(8) Pharmaceuticals
(9) Power
