Page 1 - 3-Lesson Notes-Role of the Atmosphere, Ozone Layer

SAI INTERNATIONAL SCHOOL
Class - VI
Subject - Chemistry
Topic – Air Around Us
Sub-Topic – Role Of The Atmosphere, Ozone Layer

Lesson Notes

Role of the Atmosphere:-

1. Maintains proper temperature on the earth – The atmosphere maintains the right
temperature on the earth. The heat and light of the sun first fall on the atmosphere
surrounding the earth. This blanket allows only a limited amount of heat and light to
fall on the earth’s surface. This prevents the earth from becomingtoo much hot
during day time. During the night, the heat released by the earth is not allowed to
escape by the atmosphere. This prevents the earth from cooling down too much.

2. Changes in weather – The atmosphere causes weather change. Rain, snow, and
storms occur in the atmosphere. The hot air rises and the cool air takes its place. In
this process, the winds blow.

3. Controls the natural cycles – Natural cycles such as the water cycle and the
oxygen cycle also occurs in the atmosphere.

Ozone Layer

❖ High up in the earth’s atmosphere, in the region between about 10 kilometers and
about 50 kilometers, is present a layer of ozone gas.
❖ This layer absorbs 93-95% of the ultraviolet (UV) radiation from the sun. Most of the
UV rays are harmful.
❖ Exposure to UV rays can cause skin cancer and eye problems. Therefore, the
presence of the ozone layer is very important for the existence of life.
❖ However, it is getting destroyed by increasing pollution. To avoid this, many
countries have banned the use of chemicals that can destroy the ozone, such as
chlorofluorocarbons.

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