Composition and Structure of Atmosphere
NCERT Class 11 Geography Chapter 7: Composition and Structure of Atmosphere (Pages 64–65)
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Summary of Composition and Structure of Atmosphere
Composition and Structure of Atmosphere at a Glance
CBSE
Class 11
Geography
Fundamentals of Physical Geography
7
64–65
6 study resources
Composition and Structure of Atmosphere Summary
The atmosphere is a crucial layer surrounding our planet, composed mostly of gases like nitrogen and oxygen, along with water vapor and dust particles. It is essential for life as it provides the air needed for breathing and protects us from the sun's harmful rays. The atmosphere plays a key role in weather and climate, influencing temperatures, precipitation, and wind patterns. The chapter starts by emphasizing the importance of air, pointing out that humans and all living organisms depend on it for survival. It then details the composition of the atmosphere, explaining that it contains variable amounts of gases depending on altitude, with the majority confined to about thirty-two kilometers above the Earth's surface. Carbon dioxide is highlighted for its role in trapping heat and contributing to the greenhouse effect, while ozone is noted for its protective qualities against ultraviolet radiation. Next, the chapter describes the structure of the atmosphere, which is divided into five major layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The troposphere is where most weather events occur, containing moisture and dust that impacts climate. The stratosphere is significant for its ozone layer, which absorbs harmful solar radiation, ensuring life's continuation on Earth. Each layer has different temperature profiles, with the troposphere experiencing decreasing temperatures with altitude, while the thermosphere sees increasing temperatures. Understanding these elements helps students grasp how the atmosphere operates and influences life on Earth, including phenomena like climate change and weather patterns.
