composition and structure of the atmosphere Flashcards
Define the atmosphere
The atmosphere is a thin layer of gas held to the earth by gravitational attraction - according to F.J Monkhouse.
what is the percentage of nitrogen and oxygen in the atmosphere?
Nitrogen- 78.03%
Oxygen- 20.99%
State the features of Nitrogen
1] Nitrogen constitutes the largest portion of the atmosphere
2] It has no odor, taste, or color
3] Nitrogen avoids quick burning. It would be difficult to control fire without nitrogen.
4] This gas extends upto a height of 128km
State the characteristics of oxygen
1] Life saver as it is essential for breathing
2] Helps in burning fuel
3] main source of energy
4] provides solid base to industries
5] extends upto 64km, but its concentration is confined only to 16km
State the characteristics of carbon-dioxide
1] Heaviest gas
2] important for the growth of vegetation
3] height of 32km
4] confined to lower layers only.
What are the 5 layers of the atmosphere?
the five layers of the atmosphere are :- Troposphere, Stratosphere, Mesosphere, Ionosphere and Exosphere.
State any 4 characterisitics of the troposphere
1] lowermost layer of the earth
2] average height is 16km, 8km at the poles and 18km at the equator.
3] most important layer of the earth
4] contains dust particles and over 90% of the Earth’s water vapour.
5] All vital climatic conditions and weather conditions take place in this layer.
Define normal lapse rate
Temperature decreases with height in the troposphere, roughly at the rate of 1 degree celsius for 165m of ascent. This is called normal lapse rate
why is the thickness of the troposphere greatest at the equator?
due to upward transportation of heat by strong conventional currents.
Define the Tropopause
The upper limit of the troposphere separating it from the stratosphere is called the tropopause. It is a very thin and unstable layer of 1.5km thickness only.
State the characterisitics of stratosphere
1] extends upto a height of 50km.
2]thicker at the poles than the equator.
3] temperature remains almost constant in its lower portion approx upto a height of 20km.
4] no presence of clouds, convection currents, thundering and lightning, water vapour, dust particles etc.
5] air moves in a horizontal direction.
Define a stratopause
The uppermost limit of the stratosphere is called the stratopause.
Define an ozonosphere
The lower portion of the stratosphere having maximum concentration of ozone is called ozonosphere.
state the characterisitcs of mesosphere
1] lies above the stratosphere
2] extends upto a height of 80km
3] Temperature decreases with height in this layer and falls down to -100 degree celsius at the height of 80km.
State the characteristics of ionosphere
1] extends from 80km to 400km
3] lies above mesosphere
2] contains electrically charged particles called ions.
4] Radio aves transmitted from the earth are reflected back to the earth by this layer.
