9th Grade Chapter 3 Lesson 4


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9th Grade Chapter 3 Lesson 4

  1. 1. 9 th Grade Chapter 3 Lesson 4 Pgs. 67-73 For Student Use Only
  2. 2. Storms <ul><li>Lightning: </li></ul><ul><ul><li>Lightning- abrupt discharge of electricity through the air </li></ul></ul><ul><ul><ul><li>Lightning occurs when large amount of static electricity build up in cumulonimbus clouds (perhaps because of friction between ice crystals) </li></ul></ul></ul><ul><ul><ul><li>The cloud has a different charge from the ground and opposite charges attract </li></ul></ul></ul><ul><ul><ul><ul><li>Air insults the two charges (keeps them apart) </li></ul></ul></ul></ul>
  3. 3. Storms <ul><li>Lightning: </li></ul><ul><ul><li>Lightning </li></ul></ul><ul><ul><ul><li>A stream of electrons (negative charged particles) goes from cloud to ground in a jerky pattern- this is called a stepped leader. </li></ul></ul></ul><ul><ul><ul><li>A positive stream of atoms reaches up to meet the stepped leader (usually from the tallest object around) </li></ul></ul></ul><ul><ul><ul><li>Return Stroke- (Positive and Negative meet)- electrons flow downward in a mighty current from cloud to ground </li></ul></ul></ul>
  4. 4. Storms <ul><li>Lightning: </li></ul><ul><ul><li>Lightning releases massive amounts of electricity and heats the surrounding air </li></ul></ul><ul><ul><li>Thunder- is a result of lightning heating the air </li></ul></ul><ul><ul><ul><li>Thunder- is the explosive shockwave of sound from the rapidly expanding air </li></ul></ul></ul>
  5. 5. Storms <ul><li>Lightning: </li></ul><ul><ul><li>Types of Lightning: </li></ul></ul><ul><ul><ul><li>Cloud to Ground Lightning: moves from cloud to ground </li></ul></ul></ul><ul><ul><ul><li>Cloud to Cloud Lightning: moves from cloud to cloud </li></ul></ul></ul><ul><ul><ul><li>Ground to Cloud Lightning: moves from ground to cloud </li></ul></ul></ul><ul><ul><ul><li>Heat Lightning: in summer when lightning from high altitude clouds is reflected over the horizon </li></ul></ul></ul><ul><ul><ul><li>Ball Lightning: rare phenomenon- incandescent sphere of electricity that floats in the air (not well understood) </li></ul></ul></ul><ul><ul><ul><li>Superbolt- Rare positive cloud to ground lightning </li></ul></ul></ul><ul><ul><ul><li>Hot Lightning: steady streams of electricity not a series of pulses (usually catches what it strikes on fire) </li></ul></ul></ul>
  6. 6. Storms <ul><li>Tornado: </li></ul><ul><ul><li>Tornado- narrow funnel of rapidly whirling winds </li></ul></ul><ul><ul><ul><li>Smallest but most violent storms </li></ul></ul></ul><ul><ul><ul><li>Make a distinctive roaring, hissing noise </li></ul></ul></ul><ul><ul><li>Tornado Formation: </li></ul></ul><ul><ul><ul><li>Tornado Alley- Mississippi Valley and Eastern Great Plains has the most tornadoes </li></ul></ul></ul><ul><ul><ul><li>Formed when: a low pressure system where a mass of cold dry air clashes with a mass of warm, moist air </li></ul></ul></ul>
  7. 7. Storms: <ul><li>Tornado Dangers: </li></ul><ul><ul><li>The wind is the most dangerous thing in a tornado </li></ul></ul><ul><ul><li>Wind can be from 20 -150 mph </li></ul></ul><ul><ul><li>Tornadoes are unpredictable </li></ul></ul><ul><li>Tornado Cousins </li></ul><ul><ul><li>Waterspouts- tornado over water (weaker) </li></ul></ul><ul><ul><li>Dust Devil- small funnel-like winds (winds up to 45 mph) </li></ul></ul>
  8. 8. Storms <ul><li>Hurricanes: </li></ul><ul><ul><li>Hurricane- giant whirling storms accompanied by destructive winds, torrential rains, high waves and tides. </li></ul></ul><ul><ul><li>Winds can be 74-200 mph </li></ul></ul><ul><ul><ul><li>Scientific Name for Hurricane: </li></ul></ul></ul><ul><ul><ul><ul><li>Tropical Cyclone </li></ul></ul></ul></ul>
  9. 9. Storms <ul><ul><li>Other names for hurricanes: </li></ul></ul><ul><ul><ul><li>Typhoons </li></ul></ul></ul><ul><ul><ul><li>Willy-Willies </li></ul></ul></ul><ul><ul><ul><li>Baguios </li></ul></ul></ul><ul><ul><ul><li>Cyclones </li></ul></ul></ul><ul><li>How Hurricanes Form: </li></ul><ul><ul><li>Need 2 Things </li></ul></ul><ul><ul><ul><li>Warm Oceans </li></ul></ul></ul><ul><ul><ul><li>Strong Coriolis </li></ul></ul></ul>
  10. 10. Storms <ul><li>Hurricanes </li></ul><ul><ul><li>Start with tropical disturbance </li></ul></ul><ul><ul><ul><li>Tropical Disturbance: a thunderstorm over a tropical sea </li></ul></ul></ul><ul><ul><ul><li>Tropical Depression: when enough warm air (“fuel”) has been added and the rotating winds reach a sustained 23 mph </li></ul></ul></ul><ul><ul><ul><li>Tropical Storm: when winds reach 39 mph (it is given a name at this point) </li></ul></ul></ul><ul><ul><ul><li>Hurricane- when winds reach 74 mph </li></ul></ul></ul>
  11. 11. Storms <ul><li>Hurricanes: </li></ul><ul><ul><li>Categories: </li></ul></ul><ul><ul><ul><li>1= weakest </li></ul></ul></ul><ul><ul><ul><li>2= weak </li></ul></ul></ul><ul><ul><ul><li>3= This is a major hurricane </li></ul></ul></ul><ul><ul><ul><li>4= Strong hurricane </li></ul></ul></ul><ul><ul><ul><li>5= Strongest hurricane ever recorded </li></ul></ul></ul>
  12. 12. Storms <ul><li>Hurricane Structure: </li></ul><ul><ul><li>Eye: Center of the hurricane- a region of low pressure </li></ul></ul><ul><ul><li>Eye Wall: the cylinder of thick whirling clouds and rain that surround the eye </li></ul></ul><ul><ul><li>Rain Bands: lines of thunderstorms at lower altitudes </li></ul></ul>
  13. 13. Storms <ul><li>Hurricanes </li></ul><ul><ul><li>Hurricanes stay strong if over water, but once they hit land they weaken </li></ul></ul><ul><li>Dangers of Hurricane: </li></ul><ul><ul><li>Winds </li></ul></ul><ul><ul><li>Floods- winds and low pressure push water towards land </li></ul></ul><ul><ul><li>Storm Surge- elevated water levels due to low pressure and winds </li></ul></ul>