What is important to know about Atmosphere?

Nitrogen (78%) and Oxygen (21%) are permanent gases of the atmosphere and together constitute 99% of its composition.

What is important to know about Atmosphere?

Of the remaining one percent of the atmosphere, Argon accounts for 0.93% and Carbon-di-oxide for 0.03%.

What is important to know about Atmosphere?

Daniel Rutherford discovered nitrogen in the atmosphere in 1772 CE, and Joseph Priestly discovered oxygen in 1774.

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Atmosphere

20 Key Points

10 MCQs

Study Material

The blanket of air that surrounds the Earth is called the atmosphere. It is held close to the Earth by gravitational attraction and is essential for the survival of all forms of life. This lesson covers its composition, layers, weather and climate, winds, cyclones, clouds, precipitation, rainfall and humidity.

1. Composition of the Atmosphere

The atmosphere is a mixture of gases, water vapour and dust particles. Nitrogen (78%) and Oxygen (21%) are the permanent gases; together they make up 99% and their percentages never change.

Gas	Share / Role
Nitrogen	78%; acts as a diluent and is chemically inactive; discovered by Daniel Rutherford in 1772 CE
Oxygen	21%; most important for living organisms; discovered by Joseph Priestly in 1774
Argon	0.93%
Carbon-di-oxide	0.03%; absorbs heat and keeps the atmosphere warm
Ozone	0.00006%; protects the Earth from harmful ultra violet radiation
Water vapour	0 – 0.4%; important in predicting weather

Key Points (20)

1
Nitrogen (78%) and Oxygen (21%) are permanent gases of the atmosphere and together constitute 99% of its composition.
2
Of the remaining one percent of the atmosphere, Argon accounts for 0.93% and Carbon-di-oxide for 0.03%.
3
Daniel Rutherford discovered nitrogen in the atmosphere in 1772 CE, and Joseph Priestly discovered oxygen in 1774.

Practice MCQs (10)

Test your knowledge with these practice questions.

Q1. The Normal lapse rate, the rate at which temperature decreases with height, is:

A. 6.5°C per km

B. 5.3°C per km

C. 10.6°C per km

D. 0.5°C per km

Q2. Tropical cyclones are known as 'willy willy' in:

A. the Philippines

B. the western Pacific Ocean

C. the Atlantic Ocean

D. Australia

Q3. Which of the following statements about the stratosphere is NOT correct?

A. Temperature increases with increase in height.

B. It is also called the ozonosphere.

C. Large jet planes normally fly here.

D. Almost all weather phenomena take place here.

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