Atmosphere

The atmosphere is the layer of gases that surrounds the Earth and is held in place by the force of gravity. It is composed of a mixture of gases, such as nitrogen, oxygen, carbon dioxide, and water vapor, as well as suspended particles and aerosols.

Composition of the Atmosphere

The atmosphere is primarily composed of:

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

Layers of the Atmosphere

The atmosphere is divided into five layers:

1. Troposphere: The lowest layer where weather occurs.
2. Stratosphere: Contains the ozone layer that absorbs UV radiation.
3. Mesosphere: The middle layer where meteors burn up.
4. Thermosphere: The layer where the auroras occur and contains the ionosphere.
5. Exosphere: The outermost layer that gradually transitions into outer space.

Functions of the Atmosphere

The atmosphere has several important functions:

• Protection: It shields the Earth from harmful solar radiation.
• Regulation of temperature: It helps to maintain the Earth's temperature through the greenhouse effect.
• Weather and climate: It is the medium through which weather phenomena and climate patterns occur.
• Respiration: It provides the oxygen necessary for respiration and carbon dioxide for photosynthesis.

Study Guide

Here are some key points to remember about the atmosphere:

1. What are the primary gases in the atmosphere?
2. Describe the layers of the atmosphere and their unique characteristics.
3. Explain the functions of the atmosphere and how it impacts life on Earth.
4. Discuss the greenhouse effect and its role in regulating the Earth's temperature.

[Atmosphere] Related Worksheets and Study Guides:

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