(CLASS - 7th) CHAPTER - 4 Air Around Us (Questions and the Answers)
1. Name the layers of the atmosphere.
2. How do plants absorb nitrogen ?
Plants absorb nitrogen through soil with the help of Rhizobium bacteria. This is used by plants to support their growth & development.
3. What is the importance of water vapours in the atmosphere ?
The importance of water vapours in the atmosphere is that it gets collected around the dust particles which acts as a Hydroscopic molecules and get condensed to form clouds.
4. Name the different variables of temperature.
a) Forecast of temperature.
b) Humidity
c) Rainfall
d) Velocity of air
5. What type of climate does India have ?
India have monsoonal type of climate.
E
1. What is the importance of C02 and O2 for living beings ?
Oxygen :-
a) All living organisms inhale oxygen from the surrounding to stay alive. Thus, it is a life supporting gas.
b) The atmosphere is continuously replenished of oxygen by the green plants through the process of photosynthesis and this keeps a healthy balance of oxygen in the air.
c) The growing trees & bushes is very important to maintain a balance of oxygen supply in the air.
Carbon Dioxide :-
a) The carbon dioxide gas absorbs heat from the sun.
b) It warms up the lower atmosphere of the earth's surface.
c) Humans and animals release CO2 during the process of respiration.
d) The green plants draw this co2 from the atmosphere and utilise it during the process of photosynthesis.
2. Name three major sources of pollutants in the air .Also state the ill-effects of these air pollutants.
Major sources of pollutants in the air are :-
a) Burning of fossil fuels.
b) Smoke from factories
c) Forest fire
Ill-effects of these air pollutants are :-
a) Asthma
b) Skin Cancer
c) Bronchitis
3. What is the importance of ozone gas ? Why is global warming a threat to life on the earth ?
Ozone is found in Stratosphere. This ozone layer is very important as it acts as a filter and absorbs harmful ultraviolet sun rays from reaching the earth's surface. It acts as a shield of the earth.
If the amount of Co2 is more in the air ,it can adversely affect the living beings . Since the Co2 has a property to absorb heat, it increases the temperature of the atmosphere, which in turn increases the temperature over the earth's surface & hole in ozone layer. This causes global warming which is threatening to life on the earth.
4. How is rainfall caused ? Explain it with the help of diagram.
As hot air rises high in the atmosphere where it cools down due to the presence of low temperature there. The water present in the form of water vapours condenses into tiny drops of water.
In due course of time , these tiny particles join together and form clouds. Due to further cooling, these tiny condensed droplets join and form larger droplets .
In the course of time, there droplets become so heavy that the air can not hold them. Hence, they fall down as rainfall.
5. Write the difference between weather and climate.
Weather : 1. It refers to the state of atmosphere that includes its temperature ,pressure & humidity for a specific place for a short period of time.
2. It may change in different places of the same city or locality. It covers small area.
Climate : 1. It refers to the state of atmosphere , pressure, rainfall over a long period of time.
2. It covers large area.
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
2. How do plants absorb nitrogen ?
Plants absorb nitrogen through soil with the help of Rhizobium bacteria. This is used by plants to support their growth & development.
3. What is the importance of water vapours in the atmosphere ?
The importance of water vapours in the atmosphere is that it gets collected around the dust particles which acts as a Hydroscopic molecules and get condensed to form clouds.
4. Name the different variables of temperature.
a) Forecast of temperature.
b) Humidity
c) Rainfall
d) Velocity of air
5. What type of climate does India have ?
India have monsoonal type of climate.
E
1. What is the importance of C02 and O2 for living beings ?
Oxygen :-
a) All living organisms inhale oxygen from the surrounding to stay alive. Thus, it is a life supporting gas.
b) The atmosphere is continuously replenished of oxygen by the green plants through the process of photosynthesis and this keeps a healthy balance of oxygen in the air.
c) The growing trees & bushes is very important to maintain a balance of oxygen supply in the air.
Carbon Dioxide :-
a) The carbon dioxide gas absorbs heat from the sun.
b) It warms up the lower atmosphere of the earth's surface.
c) Humans and animals release CO2 during the process of respiration.
d) The green plants draw this co2 from the atmosphere and utilise it during the process of photosynthesis.
2. Name three major sources of pollutants in the air .Also state the ill-effects of these air pollutants.
Major sources of pollutants in the air are :-
a) Burning of fossil fuels.
b) Smoke from factories
c) Forest fire
Ill-effects of these air pollutants are :-
a) Asthma
b) Skin Cancer
c) Bronchitis
3. What is the importance of ozone gas ? Why is global warming a threat to life on the earth ?
Ozone is found in Stratosphere. This ozone layer is very important as it acts as a filter and absorbs harmful ultraviolet sun rays from reaching the earth's surface. It acts as a shield of the earth.
If the amount of Co2 is more in the air ,it can adversely affect the living beings . Since the Co2 has a property to absorb heat, it increases the temperature of the atmosphere, which in turn increases the temperature over the earth's surface & hole in ozone layer. This causes global warming which is threatening to life on the earth.
4. How is rainfall caused ? Explain it with the help of diagram.
As hot air rises high in the atmosphere where it cools down due to the presence of low temperature there. The water present in the form of water vapours condenses into tiny drops of water.
In due course of time , these tiny particles join together and form clouds. Due to further cooling, these tiny condensed droplets join and form larger droplets .
In the course of time, there droplets become so heavy that the air can not hold them. Hence, they fall down as rainfall.
5. Write the difference between weather and climate.
Weather : 1. It refers to the state of atmosphere that includes its temperature ,pressure & humidity for a specific place for a short period of time.
2. It may change in different places of the same city or locality. It covers small area.
Climate : 1. It refers to the state of atmosphere , pressure, rainfall over a long period of time.
2. It covers large area.
Comments
Post a Comment