Atmosphere

The atmosphere is a layer of gases that surrounds the Earth and is held in place by gravity. It is composed of several different gases, with nitrogen and oxygen being the two most abundant. The atmosphere plays a crucial role in supporting life on Earth by regulating temperature, protecting against harmful radiation from the sun, and providing the air we breathe.

Composition of the Atmosphere

The Earth's atmosphere is composed of several gases, including:

• Nitrogen (N₂) - 78%
• Oxygen (O₂) - 21%
• Argon (Ar) - 0.93%
• Carbon Dioxide (CO₂) - 0.04%
• Trace gases such as helium, methane, and ozone

Layers of the Atmosphere

The atmosphere is divided into distinct layers based on temperature and composition:

1. Troposphere: The lowest layer where weather occurs.
2. Stratosphere: Contains the ozone layer, which absorbs UV radiation.
3. Mesosphere: The middle layer where meteors burn up.
4. Thermosphere: Contains the ionosphere, important for radio communications.
5. Exosphere: The outermost layer where the atmosphere transitions into space.

Functions of the Atmosphere

The atmosphere serves several important functions, including:

• Regulating temperature by trapping heat from the sun.
• Protecting the Earth from harmful solar radiation and meteoroids.
• Supporting life by providing oxygen for respiration.
• Playing a key role in the water cycle through evaporation and precipitation.

Study Guide

Here are some key points to remember about the atmosphere:

1. What are the two most abundant gases in the Earth's atmosphere?
2. Which layer of the atmosphere contains the ozone layer?
3. What is the role of the atmosphere in regulating temperature?
4. How does the atmosphere protect the Earth from harmful radiation?
5. Why is the atmosphere important for supporting life on Earth?

Understanding the composition and functions of the atmosphere is crucial for understanding the Earth's climate and the impact of human activities on the environment.

[Atmosphere] Related Worksheets and Study Guides:

• Earth's AtmosphereScience • Sixth Grade
• Earth's freshwater and atmosphereScience • Fifth Grade