7th Grade Chapter 6 Lesson 4


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7th Grade Chapter 6 Lesson 4

  1. 1. 7th Grade Chapter 6 Lesson 3 <ul><ul><li>Pgs. 212 - 220 </li></ul></ul><ul><ul><li>For Student Use Only </li></ul></ul>
  2. 2. Global Winds <ul><li>Wind: </li></ul><ul><ul><li>Horizontal movement of air </li></ul></ul><ul><li>Global Wind: </li></ul><ul><ul><li>Covers parts of the earth’s surface, LARGE areas </li></ul></ul><ul><ul><li>Caused by uneven heating of Earth </li></ul></ul><ul><ul><ul><li>Polar Areas- slanted sun, cooler </li></ul></ul></ul><ul><ul><ul><li>Tropical Areas- more direct sun, warmer </li></ul></ul></ul>
  3. 3. Global Winds <ul><li>Poles: </li></ul><ul><ul><li>Land temperature affects temperature of air and vice versa </li></ul></ul><ul><ul><ul><li>Cool surface- cools </li></ul></ul></ul><ul><ul><ul><li>Warm surface-warms </li></ul></ul></ul><ul><ul><li>Air travels from High pressure (polar) to Low pressure (equator) </li></ul></ul>
  4. 4. Global Winds <ul><li>Wind Zones: </li></ul><ul><ul><li>Tropical Zone (0 to 30 N and S of equator): trade winds are found here, Northeast in Northern Hemisphere, Southwest in Southern Hemisphere </li></ul></ul><ul><ul><li>Temperate Zone (30-60 N and S of Equator): prevailing winds come from the west (both hemispheres), these winds are called the westerlies </li></ul></ul><ul><ul><li>Polar Zone (60-90 N and S of equator): prevailing winds come from east direction called Easterlies </li></ul></ul>
  5. 5. Global Winds <ul><li>Other Wind Zones: </li></ul><ul><ul><li>ITCZ (Inter-Tropical-Convergence-Zone): where the trade winds meet at the equator (Hot air rising called Converging) </li></ul></ul><ul><ul><ul><li>AKA- Doldrums- no horizontal wind and ships could get stuck </li></ul></ul></ul><ul><ul><li>Horse Lattitudes (30 N and S of equator): winds are again vertical (sinking and called diverging), sailors used to have to dump horses </li></ul></ul>
  6. 6. Global Winds <ul><li>Winds: </li></ul><ul><ul><li>Subtropical highs: Areas of high pressure air found within the horse lattitudes </li></ul></ul><ul><li>Air Mass Behavior: </li></ul><ul><ul><li>2 different temperature air masses do not mix. </li></ul></ul><ul><ul><li>Polar Air meeting Subtropical air- do not mix </li></ul></ul><ul><ul><ul><li>Called a Polar Front (warm air rises up cold air pushes underneath) </li></ul></ul></ul>
  7. 7. Global Winds <ul><li>Winds: </li></ul><ul><ul><li>Polar Highs: </li></ul></ul><ul><ul><ul><li>High pressure areas in the polar regions </li></ul></ul></ul><ul><ul><ul><li>Air flows outwards from these regions </li></ul></ul></ul><ul><li>Circulation: </li></ul><ul><ul><li>Winds move down and over </li></ul></ul><ul><ul><li>Inertia- the tendency of an object in motion to stay in motion the tendency of an object at rest to stay at rest until a force acts upon it </li></ul></ul>
  8. 8. Global Winds <ul><li>Wind Movement: </li></ul><ul><ul><li>Coriolis Effect: </li></ul></ul><ul><ul><ul><li>The spinning of the earth causes the winds to curve </li></ul></ul></ul><ul><ul><ul><li>All winds in the Northern Hemisphere curve right </li></ul></ul></ul><ul><ul><ul><li>All winds in the Southern Hemisphere curve left </li></ul></ul></ul><ul><ul><li>Air Movement: </li></ul></ul><ul><ul><ul><li>Air rushes to ITCZ and curves </li></ul></ul></ul><ul><ul><ul><li>Here it piles up and sinks (horse lattitudes) </li></ul></ul></ul><ul><ul><ul><li>As the winds flow out they curve </li></ul></ul></ul>
  9. 9. Global Winds <ul><li>Winds: </li></ul><ul><ul><li>Hadly Cell- circualtion of tropical air </li></ul></ul><ul><ul><li>Rosby Waves- upper troposphere waves (heating and cooling) of air </li></ul></ul><ul><ul><li>Jet stream- high atmosphere powerful wind current, can be as fast as 250 MPH </li></ul></ul><ul><ul><ul><li>Subtropical Jet Stream- above sub-tropical areas </li></ul></ul></ul><ul><ul><ul><li>Polar front jet Stream- flows along the warm air in a polar front </li></ul></ul></ul><ul><ul><ul><li>Occur just below the tropopause (upper layer of troposphere) </li></ul></ul></ul>