Air

The physical and biological elements in the environment are dynamic in nature .changes take place slowly and suddenly in the nature of landforms. The circulation air and water brings about changes in the climatic conditions in different seasons.

Among the four major elements of environment, the atmosphere is most dynamic as changes take place in it not only from one season to another but also over shorter periods of few hours.

When air is heated it becomes lighter and goes up. Cold air is denser and heavy that is why it tends to sink down. When hot air rises, cold air from surrounding area rushes there to fill the gap. This is how air circulation takes place.

The different layer of atmosphere are-troposphere, stratosphere, mesosphere, thermosphere, exosphere.

Troposphere layer makes weather phenomena possible.

Ionosphere layer makes radio communication possible.

The ionosphere or the thermosphere protects us from meteors and obsolete satellite from outer space.

Insolation is the incoming solar energy intercepted by the earth. The amount of insolation decreases from the equator towards poles.

Temperature is measured with the help of thermometer .Outdoor temperature is measured with the help of mercury thermometer.

Maximum temperature is the highest temperature of the day recorded about 2.00 pm.

In areas where temperature is high the air gets heated and rises. This creates a low pressure area.In the area having low temperature the air is cold. It is therefore heavy. Heavy air sinks and creates a high pressure.

The scientific study of weather is called meteorology.

The stratosphere is free from water vapour and dust particle.

Moving air is called wind. Wind always blows from high pressure to low pressure.

This term refers to degree of moisture present in the air .There is a definite limit to the quantity of moisture that can be held by the air at a specific temperature.

The temperature at which the air becomes fully saturated is known as dew point.

The total amount of water vapour that is contained in the air at a given temperature is known as absolute humidity.

The ratio between actual amount of water vapour present in the air at a given temperature and the maximum amount of water vapour that the atmosphere can retain at that temperature is known as relative humidity.

Rainfall is very important for the survival of plants and animals. It brings fresh water to the earth’s surface. If rainfall is less the it may cause drought on the other hand if it is more floods will takes place.