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Temperature of the Earth (student presentation)


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student presentation
Temperature of the Earth
General Physics 1
presentation 1 group 4
24 Jan 2009
trimester 2, 2008-2009

Published in: Education

Temperature of the Earth (student presentation)

  1. 1. Chitlada, Nattapol, Nopparat, Witawat Group 4
  2. 2. Reasons for Climate Change <ul><li>2 majors facts that cause the Earth’s climate to change </li></ul><ul><ul><li>Changes in the tilt of the Earth’s axis </li></ul></ul><ul><ul><li>Variation in the shape of Earth’s orbit around the sun </li></ul></ul>© ©
  3. 3. Gravity causes Season <ul><li>The tilt of Earth’s axis of rotation and the revolution of Earth around the Sun cause seasons on Earth </li></ul><ul><li>The length of daylight varies depending on latitude and season </li></ul>© ©
  4. 4. Earth Tilt causes Season change <ul><li>Astronomer Milutin Milankovitch theorized that the Earth’s axis is not always 23.5°. The tilt changes between 22.1° and 24.5° within a cycle of about 41,000 years. </li></ul><ul><li>When the tilt is less, summers are cooler and winters milder. When the tilt is greater, the seasons are more extreme. </li></ul>
  5. 5. Earth Tilt causes Season change ©
  6. 6. Earth Tilt causes Season change <ul><li>If summers are cooler, the winter snows in the high latitudes will not melt so easily. Snow will build up from year to year, forming glaciers. </li></ul><ul><li>Compared with water and land, snow reflects more of the Sun's energy into space, causing additional cooling. The drop in temperature causes additional accumulation of snow and growth of glaciers. This further increases reflection, so temperature is reduced further, and so on. This may be how ice ages begin. </li></ul>
  7. 7. Sun causes Climate Change <ul><li>~ 70% of Earth's surface is covered by water which responds to the gravitational attraction of the Moon and Sun with a daily cycle of high and low tides. </li></ul><ul><li>Earth systems have internal and external sources of energy, both of which create heat. </li></ul><ul><li>The transfer of heat energy within the atmosphere, hydrosphere, and surface occurs as a result of radiation , convection , and conduction . </li></ul>
  8. 8. Sun causes Climate Change <ul><li>Studied by Milankovitch, the Earth is a bit closer to the Sun at some times of the year than at others. More solar energy is received when the Sun and Earth are closest [Perihelion (January)] than when they are farthest apart [Aphelion (July)]. </li></ul><ul><li>The Earth’s orbit is changing on cycles of between 90,000 and 100,000 years. As a result, the difference in solar radiation received at the perihelion and aphelion will be greater. </li></ul>
  9. 9. Summary <ul><li>The orientation of the tilt of the Earth’s axis changes over time. Like a spinning top that is winding down, the axis moves in a circle. This movement is called precession. It occurs on a 22,000-year cycle which causes the seasons to slowly shift through the year. Some 11,000 years ago the Northern Hemisphere was tilted toward the Sun in December rather than in June. Winter and summer were reversed. They will have switched again 11,000 years from now. </li></ul>
  10. 11. References <ul><li> </li></ul><ul><li> </li></ul>