Answer the following questions.
Que- What is the atmosphere?
Our earth is surrounded by a huge blanket of air called the atmosphere.
Que- Which two gases make the bulk of the atmosphere?
Nitrogen and oxygen are two gases that make up the bulk of the atmosphere.
Que- Which gas creates the greenhouse effect in the atmosphere?
The greenhouse effect occurs in the atmosphere due to carbon dioxide
Que- What is the weather?
The weather is the condition of the atmosphere from hour to hour, day to day
Que- Name three types of rainfall?
Three types of rainfall are:
- Convectional rainfall
- Orographic rainfall
- Cyclonic rainfall
Que- What is air pressure?
Air pressure is the force exerted by the weight of air on the surface of the earth.
Give reasons.
Que- Wet clothes take a longer time to dry on a humid day?
Water vapor levels in the atmosphere are high on humid days since humidity levels are high. As a result, humid air cannot carry away more water vapor and clothes take longer to dry.
Que- Amount of insolation decreases from the equator towards the poles?
Insolation is the incoming solar energy intercepted by the earth. On the equator, sunlight falls almost vertically, whereas it falls slightly at an angle at the poles. Because of this, insolation decreases from equator to pole.
Tick the correct answer.
Which of the following gases protects us from harmful sun rays?
- Carbon dioxide
- Nitrogen
- Ozone
The most important layer of the atmosphere is
- Troposphere
- Thermosphere
- Mesosphere
Which of the following layers of the atmosphere is free from clouds?
- Troposphere
- Stratosphere
- Mesosphere
As we go up the layers of the atmosphere, the pressure
- Increases
- Decreases
- Remains the same
When precipitation comes down to the earth in the liquid form, it is called
- Cloud
- Rain
- Snow
Match the following
| Trade Winds | Incoming solar energy |
| Loo | Seasonal wind |
| Monsoon | The horizontal movement of Air |
| Wind | Layer of ozone gas |
| Permanent wind | |
| Local wind |
Class 7 Geography Chapter 4 Air Notes
Nitrogen is the most plentiful gas in the air.
Green plants produce oxygen during photosynthesis.
Our atmosphere is divided into five layers starting from the earth’s surface. These are Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere
The degree of hotness and coldness of the air is known as temperature.
An important factor that influences the distribution of temperature is insolation.
The movement of air from a high-pressure areas to low-pressure areas is called wind.
A wind is named after the direction from which it blows, e.g. the wind blowing from the west is called westerly.
Winds can be broadly divided into three types.
Permanent winds – The trade winds, westerlies, and easterlies are the permanent winds.
Seasonal winds – These winds change their direction in different seasons.
Local winds – These blow only during a particular period of the day or year in a small area. For example, land and sea breeze.
Moisture in the air at any time is known as humidity.
Precipitation that comes down to the earth in liquid form is called rain.
