unit 2 lesson 2

• As molecules of air close to Earth's surface are heated by conduction


  They spread apart, and air becomes less dense
• Less dense air rises

  Transferring thermal energy to higher altitudes
• Convection


  The transfer of thermal energy by the movement of particles within matter
• Earth has several large convection cells that redistribute thermal energy around the world
• Differences in air pressure

  Cause air to flow

  
• Wind


  The movement of air from areas of high pressure to areas of low pressure

  
• Land warms faster than water

  Air over the land warms by conduction and rises, creating an area of low pressure
• Air over the water sinks

  Creating an area of high pressure because it is cooler
• Differences in pressure over the warm land and the cooler water

  Results in a sea breeze--a cool wind that blows from the sea onto the land

  
• At night, the land cools more quickly than the water


  An area of lower pressure forms over the warmer water
• Cool air over the land moves toward lower pressure over the water

  Creating a land breeze

  
• Differences in temperature


  Create differences in air pressure

  
• Warm air rises and puts less pressure on Earth than cooler air
• Cold air sinks and puts more pressure on Earth
• These differences in air pressure create local and global wind patterns

  
• Gyres


  Large circular systems of ocean currents

  
• The currents within each gyre move in the same direction


  However, the direction changes in each hemisphere because of the Coriolis effect
• Gyres in the Northern Hemisphere circle clockwise
• Gyres in the Southern Hemisphere circle counter clockwise
• Great Ocean Conveyor Belt


  A large system of ocean currents that circulates thermal energy around Earth

  
• Surface currents, upwelling, and density currents combine to form the Great Ocean Conveyer Belt

  
• The shapes of continents and other landmasses affect the direction and speed of currents

  
• Landmasses deflect the flow of water, helping create large circular systems of ocean currents called gyres