What is weather

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What is weather

  1. 1. What is weather?
  2. 2. Weather • Weather it is the condition of the atmosphere at a particular time and place .
  3. 3. What can cause the changes of weather? • Weather variables: 1) Temperature 2) Wind 3)Moisture 4)Precipitation
  4. 4. How to predict weather ? 1)Weather Balloons 2) Weather satellites
  5. 5. • 3)Doppler radar It IIt can detect :1)Precipitation 2)Wind direction 3) Wind speed
  6. 6. Insolation • It is the amount of sun energy reaching the Earth at a given time and place
  7. 7. What is the angle of insolation? • a measure of how high the sun is in the sky • measured from the horizon up to the position of the sun
  8. 8. What happens as the angle increases or decreases? • As the angle of insolation increases, intensity increases. (heat concentrated in smaller area.)
  9. 9. • As the angle of intensity decreases, heat is spread out over a larger area.
  10. 10. Low angle: Less absorbed High angle: More absorbed Earth • Intensity of insolation varies over the Earth because of the curvature of the Earth.
  11. 11. Where is intensity the greatest and lowest? • Intensity greatest near the Equator. – Sun’s rays are direct • Intensity low at the poles
  12. 12. At what time is the angle and intensity of insolation greatest? •The noon sun has the greatest angle of insolation.
  13. 13. How to measure angle of insolation ? • WE can measure ion angle of insolation
  14. 14. Why does the angle of insolation change between midday and evening? The angle of insolation decreases because the Earth’s rotation ,and the air temperature usually decrease
  15. 15. Measuring Temperature
  16. 16. Pressure • It is the weight of air pressing on a unit area.
  17. 17. • The difference of air pressure is due to unequal heating of the Earth. • Warm air masses have fewer air molecules than cold air masses.
  18. 18. What is the relation between temperature and pressure ? As the temperature increases the air particles are far away from each other decreasing the pressure As the temperature increases the pressure decreases
  19. 19. Air Pressure • Air Pressure is a measure of the force of the air pressing down on the earth’s surface
  20. 20. Air Pressure can vary at any particular point on the Earth depending on the density of the air Density = mass / volume
  21. 21. Title: Activity 2. Stop the Leak Challenge: Solution: Results and Explanation: Summary: Date: Feb. 2010 How can you stop the leak in this soda can?
  22. 22. Convection Cell -Suppose air in an area is cool and under high pressure -If a near by place is warmer and at a lower pressure -The air will move from high pressure area to a low pressure area . This is called “Surface wind”
  23. 23. • What do you think can increase the intensity of the wind ? • As the difference in pressure increases the wind intensity increases • Unequal heating and cooling of air results in difference in pressure • Where warm air will move • Up and cold air moves down making a circular pattern of rising and sinking air and wind called “Convection cell”
  24. 24. Sea Breeze
  25. 25. Land Breeze
  26. 26. Instruments used to measure ”Wind and Pressure” 1)Anemometer A device used to measure wind speed . The cups spin faster as the wind blow faster
  27. 27. 2)Weather Vane It is used to measure wind direction . It ‘s a movable arrow that points in the direction the wind blowing .
  28. 28. 3)Barometer Measures surrounding air pressure against standard air pressure

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