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Chapter 15-atmosphere


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Chapter 15-atmosphere

  1. 1. Chapter 15 Atmosphere
  2. 2. Earth’s Atmosphere <ul><li>Earth’s atmosphere, is a thin layer of air that forms a protective covering around the planet. </li></ul><ul><li>The atmosphere maintains a balance between the amount of heat absorbed by the sun and the amount of heat that escapes back out into space. </li></ul><ul><li>It also, gives Earth’s life forms protection from the sun’s UV rays. </li></ul>
  3. 3. Makeup of the atmosphere <ul><li>The atmosphere is a mixture of gases, solids, and liquids that surround the planet, and it extends from the surface of the earth to outer space. </li></ul><ul><li>The original atmosphere of earth is said to have been made up of CO2, and nitrogen, but very little oxygen. </li></ul><ul><li>As organisms, like bacteria, evolved they began to release oxygen as a by product, when they made food through photosynthesis. </li></ul>
  4. 4. Makeup of the atmosphere <ul><li>As time went by the top layer of the atmosphere became very rich in ozone (O 3 ), and allowed green plants to flourish. </li></ul><ul><li>This flourishing of plants gave an even larger output of oxygen, and aided in the evolution of other organisms. </li></ul><ul><li>Today, 78% of the gas in the atmosphere is Nitrogen, and only 21% is oxygen. </li></ul><ul><li>The other 1% includes water vapor, carbon dioxide, methane, and ozone. </li></ul>
  5. 5. Makeup of the atmosphere <ul><li>The atmosphere also contains small, solid particles of dust, salt, and pollen. </li></ul><ul><li>The dust is picked up by wind along with pollen, and the salt is picked up in ocean mist. </li></ul>
  6. 6. Lower Layers of the Atmosphere <ul><li>The lowest layer of the atmosphere, where almost all of your activity takes place is called the troposphere. </li></ul><ul><li>It has 99% of all the water vapor, and 75% of all the other atmospheric gases. All of our weather and clouds occur in the troposphere. </li></ul><ul><li>The layer above the troposphere is called the stratosphere and is 11km above the surface and extends to 50km. The ozone layer is located in this layer of the atmosphere. </li></ul>
  7. 7. Upper Layers of the Atmosphere <ul><li>Above the stratosphere is the mesosphere, which acts to absorb the suns energy. </li></ul><ul><li>Next, is the Thermosphere, which is the thickest layer, and has very high temps due to its proximity to the sun. </li></ul><ul><li>Within the mesosphere and thermosphere is what is called the ionosphere, which is a layer of electrically charged particles. </li></ul><ul><li>The ionosphere allows radio waves to travel from one place to another. </li></ul>
  8. 8. Exosphere <ul><li>The exosphere starts at the top to the thermosphere and continues until it merges with space. In this region of the atmosphere, Hydrogen and Helium are the prime components. </li></ul><ul><li>This is the atmosphere that our space shuttles orbit the earth. </li></ul><ul><li>H.W. 433 pg 1-4 & pg 448 1-5 </li></ul>
  9. 9. Atmospheric Pressure <ul><li>Atmospheric gases extend hundred kilometers above the Earth. Earths gravity is responsible for pulling these gases down toward the surface. </li></ul><ul><li>It is the weight of these gases, due to gravity, that pushes down on the air in the troposphere and is known as atmospheric pressure. </li></ul><ul><li>As you go up in altitude there is less atmospheric pressure because you have less atmospheric layers above you, pushing down on you. </li></ul>
  10. 10. Atmospheric Temperature <ul><li>Temps of the thermosphere are very high because it is directly exposed to the suns energy. As the suns energy passes through the thermosphere temps slowly decline. </li></ul><ul><li>The troposphere could have high temps as well. This is due to the sun warming the surface of earth, which then warms the air in the troposphere. </li></ul>
  11. 11. The ozone layer <ul><li>The ozone layer is held in the stratosphere, and contains ozone gas, which is 3 oxygen molecules. </li></ul><ul><li>This layer shields us from the UV rays from the sun, which could cause skin damage, ike melanoma. </li></ul><ul><li>Pollutants, like car exhausts expel things called chlorofluorocarbons which take an O from the O 3 molecule and destroys the ozone layer. </li></ul><ul><li>When we speak of a hole in the ozone layer, we actually mean that a hole in the atmosphere exists that is allowing harmful amounts of UV light to reach the surface of the earth. </li></ul>
  12. 13. Energy transfer in the Atmosphere <ul><li>The Sun provides most of earths energy, and when the suns energy is received by the Earth 3 things could happen: </li></ul><ul><li>Some energy is reflected back into space by clouds. </li></ul><ul><li>Some is absorbed by the atmosphere </li></ul><ul><li>Some is absorbed by the surface of the earth. </li></ul>
  13. 14. Heat energy <ul><li>Heat is the transfer of thermal energy from an object with a higher temp to one with a lower temp. </li></ul><ul><li>This transfer of thermal energy occurs in three ways: </li></ul><ul><li>1) Conduction- this is the transfer of heat from one molecule to another through physical contact. </li></ul><ul><li>If you put a spoon into a hot bowl of soup, the spoon will get warmer because it conducts heat from the hot soup. </li></ul>
  14. 15. Heat energy <ul><li>Radiation- this is thermal energy that moves away from its source in all directions in the forms of waves. Ex: The suns energy and a microwave oven uses radiation to heat things with thermal energy. </li></ul><ul><li>Convection is the transfer of heat by currents within a fluid or a gas. </li></ul><ul><li>Ex: hot air rising off the surface of a radiator. </li></ul>
  15. 16. The water cycle <ul><li>All of the water that is part of Earth is called the hydrosphere. </li></ul><ul><li>There is a constant cycle of water between the atmosphere and the hydrosphere that plays a big role in determining weather patterns and climates. </li></ul><ul><li>Bodies of water evaporate due to the suns energy and enter the atmosphere as water vapor. </li></ul><ul><li>When the water vapor cools it returns to earth as liquid in the form of rain or solid snow. </li></ul><ul><li>That cooling process of water vapor is called condensation. </li></ul>
  16. 17. The water cycle <ul><li>When condensation occurs very high with in the atmosphere, clouds form. </li></ul><ul><li>Clouds are made of tiny water droplets that eventually collide with other tiny water droplets to form rain. </li></ul><ul><li>The rain that falls from clouds is called precipitation. And completes the water cycle. </li></ul><ul><li>H.W pg 438 pg 438 ques. 1-4 </li></ul><ul><li>pg 448 ques 6-15 </li></ul>
  17. 19. Air Movement <ul><li>Because of certain surface features, Earth gets heated unevenly by the sun. This causes warmer air is some places and cooler air in other places. </li></ul><ul><li>When air is heated it expands and is considered to be a low pressure system. </li></ul><ul><li>When air is cooled it contracts and is considered to be a high pressure system. </li></ul><ul><li>Wind is the transfer of high pressure air to an area of low pressure air. </li></ul>
  18. 20. Air Movement <ul><li>So, cold air from the poles moves toward the hot air near the equator in the form of convection (wind) currents. </li></ul><ul><li>The earths rotation causes the deflection of air in different directions. Wind moving north above the equator is deflected to the right. </li></ul><ul><li>Air moving south below the equator is deflected to the left. </li></ul><ul><li> </li></ul>
  19. 22. Global winds <ul><li>Sea breeze- these are winds that blow from the sea or ocean over land, during the day. This occurs b/c during the day the land is heated more than the water and the high pressure air over the water moves to the lower pressure air over the land. </li></ul><ul><li>Land breezes- are the complete opposite of sea breezes and occur at night. This occurs b/c at night the land cools faster than the water. </li></ul><ul><li>H.W. due next class on looseleaf pg 450 ques 1-19 </li></ul>
  20. 23. Test one Week