Air - Class 7 Geography - Extra Questions

Very Short Answer Type Question.
How is atmosphere important for us?

Atmosphere protects us from the harmful rays and scorching heat of the sun.


Differentiate between weather and climate. How do they influence human activities?

Weather and climate have different connotations. Weather refers to the state of the atmosphere at any given time denoting the short-term variation of atmosphere in terms of temperature, pressure, wind, moisture, cloudiness, precipitation and visibility. Weather is highly variable. On the other hand, climate may be simply defined as average weather. The term climate denotes a description of aggregate weather conditions.
    The elements of weather and climate affect the human activities in their own way. Some of these elements directly related to our physical and mental energy and which largely determine our health and happiness. For instance, high temperature combined with high relative humidity produces sultry weather which does not favour either physical or mental labour, this factors closely related to our physical comfort and efficiency.  Economic activity of people largely determined by the weather and climatic conditions of that particular place. Thus these are the most effective and most powerful components of our natural environment.


Correct me if I am wrong

Weather describes the average pattern of climate conditions of a region over a period of 30-35 years.

False. Climate describes the average pattern of weather conditions of a region over a period of 30-35 years.

Weather is an atmospheric condition over a short period of time whereas climate is a weather pattern or condition over long periods of time.


Why are trade winds known as permanent winds?

The wind blowing from sub-tropical high-pressure belts towards the equatorial low-pressure belt is known as trade winds. They are strongest during winter and weakest during summer.  The trade winds blow with great regularity and steadiness. That is why trade winds are known as permanent winds. 


Answer the following question briefly
What is air pressure?

The pressure exerted by the weight of air on the earth's surface is known as air pressure.


Match the List I with List 2.


Trade winds    -  Permanent wind
Loo                  -  Local wind
Monsoon         - Seasonal wind
Wind                -  Horizontal movement of air


Very Short Type Question
What is the nature of cold air?

It has tendency to go down.


Answer the following question very shortly.
What is weather?

Weather is hour-to-hour, day-to-day condition of the atmosphere.


Very Short Type Question
What is an important feature of Stratosphere?

Stratosphere contains a layer of ozone gas.


Short Answer Type Question.
Give an account of atmosphere.

Atmosphere is the thin layer of air that surrounds the earth. It is made up of various gases such as oxygen, nitrogen, carbon dioxides, dust particles and water vapour. The gravitational force of the earth holds the atmosphere around it. It protects us from harmful rays and scorching heat of the sun. The changes in atmosphere produce changes in the weather and climate.


Why is there no air pressure on the moon?

The Moon is considered not to have an atmosphere because it cannot absorb measurable quantities of radiation, does not appear layered or self-circulating, and requires constant replenishment due to the high rate at which its gases get lost into space.


Very Short Answer Type Questions:
What is the function of carbon dioxide?

Carbon dioxide absorbs the heat radiated by the earth and thus keeps the planet warm. 


What is atmosphere? Write about its different layers.

An atmosphere is a layer or a set of layers of gases surrounding a planet. An atmosphere is more likely to be retained if the gravity it is subject to is high and the temperature of the atmosphere is low. 
The atmosphere can be divided into layers based on its temperature. These layers are the troposphere, the stratosphere, the mesosphere and the thermosphere. A further region, beginning about 500 km above the Earth's surface, is called the exosphere.


Where is air pressure highest?

Air pressure is highest at the sea level.


Long Answer
Give an account of the different layers of the atmosphere.

Our atmosphere has five different layers. They are:
1. Troposphere: This is the most important layer of the atmosphere with an average height of 13 km from the earth. It is in this layer that we find the air that we breathe. Almost all the weather phenomena such as rainfall, fog and hailstorm occur here.
2. Stratosphere: This layer extends up to a height of 50 km. It presents the most ideal condition for flying airplanes. It contains a layer of ozone gas which protects us from the harmful effect of the sun rays.
3. Mesosphere: This layer extends up to a height of 80 km. Meteorites bum up in this layer on entering from the space.
4. Thermosphere: In this layer, the temperature rises very rapidly with increasing height. The ionosphere is a part of this layer. It extends between 80-400 km. This layer helps in radio transmission. Radio waves transmitted from the earth the reflected back to the earth by this layer.
5. Exosphere: It is the uppermost layer where there is very thin air. Light gases such as helium and hydrogen float into space from here.


Short Answer
Why do astronauts wear special protective suits when they go to the moon?

Astronauts must wear spacesuits whenever they leave a spacecraft and are exposed to the environment of space. In space, there is no air to breath and no air pressure. Space is extremely cold and filled with dangerous radiation. Without protection, an astronaut would quickly die in space.


Short Answer
Write short note on the distribution of air pressure in atmosphere.

Air pressure is the pressure exerted by the weight of air on the earth's surface. As we go up the layers of the atmosphere, the pressure falls rapidly. The air pressure is highest at the sea level and decreases with height. Horizontally the distribution of air pressure is influenced by the temperature of the air at a given place. In areas where the temperature is high the air gets heated and rises. This creates a low-pressure area. In areas having lower temperature, the air is cold, hence, it is heavy. Heavy air sinks and creates a high-pressure area.


Class 7 Geography Extra Questions