Atmosphere Introduction Quiz

Atmosphere - Introduction

• The atmosphere is the blanket of air surrounding the Earth, densest at sea level and thinning rapidly upwards.
• It is composed of 78.03% nitrogen, 20.95% oxygen, 0.94% argon, and traces of carbon dioxide, hydrogen, and other gases.
• The lower part of the atmosphere is denser due to gravity, resulting in decreasing density with increasing height.

Factors Affecting Air Pressure

• Atmospheric pressure depends on altitude, temperature, and water vapour.
• Air pressure decreases with increasing altitude.
• Temperature decreases with increasing height above sea level at a rate of 0.6°C per 10 meters.
• The main causes of temperature decrease with increasing height are:
  • The lower atmosphere is denser and absorbs a larger amount of heat.
  • The upper atmosphere is thinner and has a low capacity to hold heat.
  • The atmosphere is mainly heated by conduction and radiation from the Earth's surface.
• A volume of humid air with water vapour is lighter than a volume of dry air.

Composition of the Atmosphere

• The atmosphere is a gaseous realm composed of a uniform mixture of permanent gases.
• The composition of the atmosphere is:
  • Nitrogen: 78.03%
  • Oxygen: 20.95%
  • Argon: 0.93%
  • Carbon Dioxide: 0.03%
  • Hydrogen: 0.01%
  • Others: 0.05%
• The atmosphere also contains water vapour, dust particles, smoke, and pollens.

Structure of the Atmosphere

• The atmosphere can be divided into five layers based on its structure:
• Troposphere: The lowest layer, closest to the surface, suitable for human life, with a decrease in temperature with increasing altitude at a rate of about 6.4°C per km.
• The other layers are:
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere