THE ATMOSPHERE

• What surrounds and protects the Earth?

  A thin blanket of gases called the atmosphere
• What is the composition of the atmosphere?


  • 78% nitrogen
  • 21% oxygen
  • 1% water vapour, carbon dioxide (CO₂), and other gases
• What causes atmospheric pressure?


  Gravity pulls the gases in the atmosphere close to the Earth
• What are the layers of the atmosphere separated by?


  Pauses
• Where are most clouds found in the atmosphere?

  In the troposphere
• In which layer do jet airplanes typically fly?

  In the stratosphere
• Where is the ozone layer located?


  In the stratosphere
• How high is the boundary between the troposphere and the stratosphere?


  11 km
• How does latitude affect climate?


  Places near the equator receive more heat than places further north
• What happens to heat as it moves from warm regions to cold regions?


  Heat flows from warm regions to cold regions
• What do prevailing winds result from?


  The continuous cycle of heat moving from the equator to the poles
• What are the steps of the water cycle?


  1. Evaporation
  2. Condensation
  3. Precipitation
  4. Runoff
• What is the average temperature of the Earth?


  Approximately 15°C
• What is the greenhouse effect?


  The trapping of heat in the atmosphere by greenhouse gases
• What gases contribute to the greenhouse effect?


  Water vapour and CO₂
• What is the weight of the atmosphere on a person?


  About 1,000 kg
• What is wind?


  Moving air
• What causes wind to form?

  Changes in air pressure
• How does warm air behave compared to cold air?


  Warm air expands, becomes less dense, and rises
• What happens when cold air moves?

  It pushes the warm air away
• What are the three wind belts in the atmosphere?

  1. Near the equator (low pressure)
  2. At 30° latitude (high pressure)
  3. At 60° latitude (low pressure)
• What is the Coriolis effect?


  The deflection of winds due to the Earth's rotation
• How are winds named?

  Winds are named after the direction from which they blow
• What are the three types of rainfall?

  1. Relief rainfall
  2. Convectional rainfall
  3. Frontal (cyclonic) rainfall
• What is relief rainfall?


  Rain produced when air is forced to rise
• What happens during convectional rainfall?


  Warm, moist air rises rapidly and cools, causing rain
• What is frontal (cyclonic) rainfall?


  Rain that occurs when cold air pushes warm air upwards
• What is the water cycle?


  The continuous movement of water through evaporation, condensation, precipitation, and runoff
• What is the effect of the Labrador Current?


  It lowers the temperature of coastal waters off Canada and North America
• What is the North Atlantic Drift?


  A warm ocean current that increases coastal temperatures
• What is the Canaries Current?


  A cold ocean current that contributes to drought conditions
• What are the effects of ocean currents on weather and climate?


  • Warm currents heat the air above them
  • Cold currents cool the air above them
  • They influence precipitation patterns
• What is the average energy received from the sun per hour for each square metre?


  164 watts
• What percentage of solar energy is absorbed by the Earth's surface?


  50%
• What percentage of solar energy is reflected back to space?

  25%
• What percentage of solar energy is absorbed by the atmosphere?


  25%
• What is the importance of the greenhouse effect?


  • Traps heat in the atmosphere
  • Keeps the Earth warm enough for life
  • Allows plants to grow and animals to survive
• What are the three main types of clouds?

  Cirrus, cumulus, and stratus
• What is the process of condensation in the water cycle?


  Water vapour cools and turns into tiny water droplets
• What happens when air becomes saturated?

  It cannot hold any more water vapour, leading to condensation