Atmosphere

Definition

The atmosphere is the layer of gases surrounding the Earth that is retained by the planet's gravity. It protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night.

5 Must Know Facts For Your Next Test

1. The atmosphere is composed primarily of nitrogen (78%), oxygen (21%), and argon (0.9%), with trace amounts of other gases such as carbon dioxide.
2. Atmospheric pressure decreases with increasing altitude, as the weight of the overlying air column decreases.
3. The atmosphere plays a crucial role in the water cycle, allowing for the transport and distribution of water vapor through evaporation, condensation, and precipitation.
4. The greenhouse effect, caused by the absorption and trapping of infrared radiation by atmospheric gases, helps regulate the Earth's temperature and make it habitable.
5. Atmospheric circulation patterns, driven by differences in temperature and pressure, create global wind systems that influence weather and climate patterns.

Review Questions

• Explain how the composition and structure of the atmosphere contribute to its role in protecting life on Earth.
  • The Earth's atmosphere is composed of various gases, with nitrogen and oxygen being the most abundant. This specific composition, along with the layered structure of the atmosphere, plays a crucial role in protecting life on Earth. The troposphere, the lowest layer, contains the air we breathe and is the site of weather phenomena. The stratosphere above it houses the ozone layer, which absorbs harmful ultraviolet radiation from the Sun, shielding the planet and its inhabitants. Additionally, the greenhouse effect, caused by the trapping of infrared radiation by atmospheric gases, helps regulate the Earth's temperature, making it habitable for a wide range of life forms.
• Describe how changes in atmospheric pressure with altitude affect the behavior of physical systems.
  • Atmospheric pressure decreases with increasing altitude, as the weight of the overlying air column decreases. This change in pressure has significant implications for physical systems. For example, the lower atmospheric pressure at higher altitudes leads to a reduction in the boiling point of water, which can affect cooking and other processes that rely on specific temperature thresholds. Additionally, the decrease in pressure with altitude can impact the performance of mechanical devices, such as aircraft engines, which rely on the density of the surrounding air for efficient operation. Understanding the relationship between altitude and atmospheric pressure is crucial in various scientific and engineering applications, from meteorology to aviation.
• Analyze the role of atmospheric circulation patterns in shaping global weather and climate.
  • Atmospheric circulation patterns, driven by differences in temperature and pressure, play a fundamental role in shaping global weather and climate. These patterns, which include global wind systems like the jet stream, the Hadley cells, and the trade winds, are responsible for the transport and distribution of heat, moisture, and other atmospheric constituents around the planet. The interactions between these circulation patterns and local geographic features, such as mountains and ocean currents, lead to the formation of diverse climate zones and weather phenomena, from deserts and rainforests to hurricanes and monsoons. Understanding the complex interplay between atmospheric circulation and the Earth's surface is crucial for accurately predicting and modeling weather patterns and long-term climate trends, which have significant implications for human activities and the global ecosystem.

Related terms

Troposphere: The lowest layer of the atmosphere, extending from the Earth's surface to an altitude of about 6-20 km, depending on latitude. It contains the air we breathe and is the site of most weather phenomena.

Stratosphere: The layer of the atmosphere above the troposphere, extending from about 20 km to 50 km altitude. It contains the ozone layer, which absorbs harmful ultraviolet radiation from the Sun.

Barometric Pressure: The force exerted by the weight of the atmosphere at a given point, measured in units of pressure such as pascals or millibars.