Air makes a very thick layer around the earth called atmosphere.
# Atmosphere Review
- Temperature decreases as the height increases by 6.50c per km.
- Upper most part of the troposphere is called tropopause.
- Troposphere is responsible to determine the weather and climate (e.g. Raining, cloud, storming, fogs etc.)
- Temperature increases as the height increases in stratosphere.
- The upper layer of stratosphere is called stratopouse.
- The region where the ozone (O3) lies in the stratopause is called ozone layer.
# Ozone Layer
- The ozone layer absorbs about 99% ultraviolet radiation coming from the sun.
- Ozonosphere is about 35 km thick.
- Ozone is formed the following ways by radiation
O2 + O ® O3 (Ozone)
- The reduction of ozone layer due to chloro fluoro carbon, methyl chloro form carbon tetra chloride and methyl bromide is called depletion of ozone layer.
# Effects of depletion of ozone layer.
- It causes skin burning, lung and breast cancer, leukemia, blindness
b. Growth of aquatic and amphibian plants affected
c. Loss of productivity of living beings
d. The depletion of O3 layer may bring about significant changes in climate and cause green house effect.
- The depletion of ozone layers causes eye cancer in cattles.
# Protection of ozone layer
- By banning the production and use of CFC.
- By bringing awareness of ozone depletion in people.
- By recapturing CFC released from the air conditioners, refrigerators and other machineries using them.
# Green House Effect
- The house made up of green glasses which can trap the solar radiation in it is called a green house.
- Off season fruits and vegetables can be grown with the help of green house.
- Carbon dioxide, nitrous oxide, methane; CFC, water vapour protect the solar radiation to wards the earth. That means these gases help the earth to act as a green house. So these gases are called green house gases and when amount of these gases increased the temperature of the earth is also increased. This increment in temperature is called green house effect.
# Effects of green house effect
- It increases the temperature of the atmosphere.
- On human, it helps spreading diseases like malaria.
- It helps breeding, growth and spreading of insects.
- Reduces crop yields by reducing the soil moisture.
- The change in climate pattern changes the crop pattern.
# Ways of controlling green house effect
- By increasing forestation
- By reducing the use of fossil fuels.
- By banning deforestation
- By banning the use of CFC
- By using unleaded petrol in vehicles
- By using biogas for domestic purposes
# Industrial gases
- The gases like SO2, CO2, CO, NO2 dust and smoke are produced by industries are called industrial gases.
- The increment in the amount of industrial gas in the atmosphere pollute the air is called air pollution.
# Effects of air pollution
- Produce diseases of neck, breast and longs.
- Acid rain
- Raise in temperature)
1. The temperature of stratosphere raises with increase in height.
Ans- On the upper layer of stratosphere i.e. on ozone layer, due to the excessive amount (about ((%) of absorption of harmful UV- rays from the sun occurs theat results in the increase in tempeerature. So, the temperature of stratosphere raises with increase in height.
2. Strotosphere (Ozone layer) is said to be protective layer.
Ans- Stratosphere (ozone layer) helps in maintaining balance of temperature and water of the earth. About 99% of the total UV rays present in the sunlight are absorbed by this layer. This layer prevents us from such radiations and also from increasing temperature of the earth. So it is said to be protective layer.
3. The temperature of the stratosphere rises as we go up.
Ans- The stratosphere contains ozone. The ozone absorbs the high frequency UV radiations coming from the sun and the other stars. Due to the absorption of the UV radiations at the upper surface the temperature of the stratosphere rises as we go up.
4. There is a fall in temperature in the mesosphere as the height from the earth increases.
Ans- The mesosphere does not contain enough ozone the absorb UV radiation. Due to this reason, the temperature of the mesosphere falls from -20C to -920C as the height from the earth increase.
5. Infra-red ray from the sun can easily arrive to the earth’s surface but the ray reflected from the earth’s surface cannot travel back to space.
Ans- The wave length of the infra-red present in the sun is shorter, so it can penetrate from the atmosphere. But the wavelength of the infra-red ray reflected back from the earth is longer therefore it cannot pass through the atmosphere.
6. An artificial green-house is used to grow summer vegetables even in winter.
Ans- The tempereature inside an artificial green house is comparatively greater than that of outside. Therefore, an artificial green house is used summer vegetables can be grown even in winter.
7. The temperature inside an artificial green house in comparatively more than that of outside.
Ans- The glass used in the construction of green house allows passing short waves only through it. When the short wave of the sun strike on the earth surface, they change into infra-red radiation or long waves and they cannot escape out easily through the glass. Thus, the temperature inside an artificial green house is comparatively more than that of outside.
8. If there are no green house gases in the atomosphere, there wouldn’t be the existence of life.
Ans- If there were no green house gases in the atmosphere, heat wouldn’t be stored on the earth. Consequently, the teperature of the earth would be less by 39C than the present temperature. In this way, ice would cover the earth. As a result, there wouldn’t be the existence of life.
9. Troposphere is also called layer.
Ans- The temperature of the troposphere is variable according to its height. It decreases as the increases in height. So troposphere is also called variable layer.
10. It is better not to overuse refrigerator with CFC.
Ans- Refrigerator with CFC release chlorofluorocarbons in a atmosphere if we use them. The chlorofluorocarbons reach the atmospheres slowly and deplete ozone layer. Due to ozone layer depletion, plants and animals suffer from different diseases. Human beings suffer sunburn, skin cancer, cateract, skin wrinkling etc. So it is not better to use refrigerator with CFC.
11. Exosphere is called fringe region.
Ans- The exosphere forms the outermost layer of atmosphere. So it is also called as frings region.
12. Temperature of thermosphere is very high.
Ans- The gass in thermosphere are NO and O2 in ionized form. It’s temperature ranges from -92oC to 1200oC. The reason for so high temperature is that this layer is close to the sun.
13. Thermosphere is also called ionosphere.
Ans- Termosphere is also called ionosphere because the temperature of this layer is so high that all the gases present in this layer exists in the form of ions.
14. Troposphere is responsible for the change in weather.
Ans- Troposphere is responsible for the change in weather because various activities related to weather like cloud formation, rain, frost, hailstorm, fog etc. Occur in this layer of atmosphere.
15. Troposphere is influenced at the maximum by the human activities.
Ans- Troposphere is influenced at the maximum by the human activities because the troposphere is the lowermost layer of the atmosphere in which we live. We exchange nitrogen, oxygen, carbon and water like biogeochemical from the nature.
16. The atmospheric pressure is maximum is troposphere.
Ans- Since the troposphere is the lowermost layer of the atmosphere and has the thickest air, the atmosphric pressure is maximum in troposphere.
17. The temperature of thermosphere is very high but spacecrafts passing it are not affected.
Ans- as the thermosphere is near to the sun, it is directly exposed to sun, the temperature of this layer is very high. However, the air present in this layer is very thin. Hence the effect of this very high temperature is not observed on space craft passing by.
18. It is necessary to protect the ozone layer.
Ans- It is necessary to protect the ozone layer because of the following reasons:
– Ozone layer protects the organisms from the harmful effects of UV rays.
– Ozone layer maintains and balances temperature and climate for the life.
19. The scientists are trying to cut off the use of coal and petroleum as fuels.
Ans- When coal and petroleum are burnt, carbon dioxide gas is produced. Carbon dioxide is a green house gas and cause global warming. Global warming has negative impacts on life and environment. Thus, the scientists are trying to cut off the use of coal and petroleum as fuels.
20. Ozone is both advantageous and disadvantageous for us.
Ans- Ozone in troposphere is not good. The ozone of troposphere may damage the lungs badly so it is disadvantageous. It is advantageous in stratosphere because if protects us from the harmful effects of UV rays of the sun. Hence, ozone is both advantageous and disadvantageous for us.
21. Oxides of nitrogen also cause ozone layer depletion.
Ans- In the presence of UV rays, NO and O3 react with ozone and form O2 and NO2, NO2 again attacks on ozone to form N2 O3 and O2. The form of a chain the chemical reaction continues and it causes ozone layer depletion. Thus, oxides of nitrogen also cause ozone layer depletion.
22. There is warm inside a green house.
Ans- The glass used in the construction of green house allows passing short waves only through it. When the short wave of the sun strike on the earth surface, they change into infra-red radiation or long waves and they cannot esacape out easily through the glass. Thus, it makes warm inside the glass house.
23. Over green house is disadvantageous.
Ans- Over green house causes global warming. It may affect the water cycle system badly. It may spread many of diseases and increases harmful insects. It reduces the crop yielding and changes the climatic pattern. Thus over green house is disadvantageous.
24. Green house is advantageous.
Ans- Green house is advantageous because it maintains the suitable temperature of the earth at days and nights. In the presence of suitable temperature only the living things can survive.
25. The atmosphere makes it possible for the living things to survive on the earth.
Ans- The atmosphere provides the suitable temperature and contains many essential things for life. Some such things are nitrogen, oxygen, carbon-dioxide and water vapour. Similarly it has ozonosphere, which protects the living thing from the harmful effects of UV rays of the sun. Hence, the atmosphere makes it possible for the living things to survive on the earth.
26. The roof of green home is made slanted.
Ans- The roof of green house is made slanted to allow the large amount of solar rays inside.