Geo: Chapter Three, Section One


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Chapter Three, Section One

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Geo: Chapter Three, Section One

  1. 1. Chapter Three, Section One Seasons and Weather
  2. 2. What causes the changing seasons? <ul><li>Earth revolves around sun </li></ul><ul><li>Earth’s tilt (23.5 degree angle) allows a more direct line to sun’s rays </li></ul><ul><li>As Earth continues to move, location becomes either further or closer to direct line with sun </li></ul><ul><li>Amount of sun affects atmospheric pressure, temperature, rainfall, hence we have our distinct seasons </li></ul>
  3. 3. Where are the tropics? <ul><li>Tropic of Cancer - northern tropic </li></ul><ul><li>Tropic of Capricorn - southern tropic </li></ul><ul><li>Solstice : the day on which sun’s rays shine directly overhead at noon at either Tropic </li></ul><ul><li>Summer solstice--longest day of year </li></ul><ul><li>Winter solstice--shortest day of year (depending on where you live) </li></ul><ul><li>Equinox : biannual times when days and night all over the world are equal in length </li></ul><ul><ul><li>Equinoxes mark the beginning of spring and autumn </li></ul></ul>
  4. 4. What is the difference between weather and climate? <ul><li>Weather : condition of atmosphere at a particular location and time </li></ul><ul><li>Climate : term for weather conditions at a particular location over a long period of time </li></ul>
  5. 5. What causes weather? <ul><li>Many conditions affect weather: </li></ul><ul><ul><li>Amount of solar energy </li></ul></ul><ul><ul><li>Water vapor: cause precipitation </li></ul></ul><ul><ul><li>Cloud cover: hold water vapor </li></ul></ul><ul><ul><li>Landforms and bodies of water </li></ul></ul><ul><ul><li>Elevation: as increase, air is thinner, less able to hold moisture </li></ul></ul><ul><ul><li>Air movement: winds </li></ul></ul>
  6. 6. Is all Precipitation the same? <ul><li>NO, DUH!!!! </li></ul><ul><li>1) Convectional: characteristic to hot climates; morning sunshine heats warm moist air; clouds form in afternoon, rain falls </li></ul><ul><li>2) Orographic: characteristic of mountain areas; storms drop rain on windward side of mountain, creates rain shadow on leeward (opposite) side; the rain shadow effect </li></ul><ul><li>3) Frontal: characteristic of mid-latitude frontal storms; cold dense air push lighter warmer air upward, causing precipitation to form </li></ul>
  7. 7. Weather Extremes
  8. 8. Hurricanes <ul><li>Storms that form over warm, tropical ocean waters </li></ul><ul><li>Also called: in Asia - typhoons; in Australia - tropical cyclones, willy-willies; in the Philippines - baguios; in Mexico - chubascos </li></ul><ul><li>Places where ocean water temperature is 80 degrees or higher, huge amounts of moisture and heat energy is picked up. </li></ul><ul><li>Water-laden (or filled) winds flow into core, or “eye” </li></ul><ul><li>The “eye” can be 10 to 20 miles across and has clear, calm skies </li></ul><ul><li>Winds around eye can be as strong as 200 miles per hour </li></ul><ul><li>Clouds and winds can stretch over large areas, up to 500 miles </li></ul><ul><li>Low-lying coastal areas are vulnerable </li></ul>
  9. 9. Tornadoes <ul><li>Form quickly, without warning </li></ul><ul><li>Also known as a twister, powerful funnel-shaped column of spiraling air </li></ul><ul><li>Cold, dry air collides with warm, moist air </li></ul><ul><li>Winds swirl counter-clockwise around low-pressure center </li></ul><ul><li>Winds may read 300 mph </li></ul><ul><li>Usually flat plain areas are vulnerable </li></ul><ul><li>Tornado Alley: midwest US </li></ul>
  10. 10. Blizzards <ul><li>Common in Senegal, chuckle, chuckle </li></ul><ul><li>Heavy snowstorm with high winds (35 mph) </li></ul><ul><li>Some parts of US are frequently hit with snowstorms - snowbelts around Great Lakes </li></ul>
  11. 11. Droughts <ul><li>Long period of time without rain or with very minimal rainfall </li></ul><ul><li>1930s in US --dust bowl </li></ul>
  12. 12. Floods <ul><li>Water spreads over land not normally covered </li></ul><ul><li>Can be from melting snow, rainwater filling small streams, overflowing rivers </li></ul>
  13. 13. Chapter 3, Section 1 <ul><li>What did we learn? </li></ul><ul><li>Now: video time </li></ul><ul><li>Homework: 1) blog 2) pre-reading for Tuesday: page 54 - 58 3) worksheets: page 8 and 9 </li></ul>