Atmospheric Processes - Radiation
After a brief discussion of heat transfer processes in general, this activity will focus on radiation. Students will investigate how different surfaces absorb heat and apply their experience with the surfaces to interpret real-world situations.
Background
Heat Transfer
Practically all of the energy that reaches the earth comes from the sun. Intercepted first by the atmosphere, a small part is directly absorbed, particularly by certain gases such as ozone and water vapor. Some energy is reflected back to space by clouds and the earth's surface. Most of the radiation, however, is absorbed by the surface.
Energy is transferred between the earth's surface and the atmosphere in a variety of ways, including radiation, conduction, and convection. The graphic below uses a campstove to summarize the various mechanisms of heat transfer. If you were standing next to the campstove, you would be warmed by the radiation emitted by the gas flame. A portion of the radiant energy generated by the gas flame is absorbed by the frying pan and the pot of water. By the process of conduction, this energy is transferred through the pot and pan. If you reached for the metal handle of the frying pan without using a potholder, you would burn your fingers! As the temperature of the water at the bottom of the pot increases, this layer of water moves upward and is replaced by cool water descending from above. Thus convection currents that redistribute the newly acquired energy throughout the pot are established.
Atmospheric Processes - RadiationAfter a brief discussion of heat transfer processes in general, this activity will focus on radiation. Students will investigate how different surfaces absorb heat and apply their experience with the surfaces to interpret real-world situations.BackgroundHeat TransferPractically all of the energy that reaches the earth comes from the sun. Intercepted first by the atmosphere, a small part is directly absorbed, particularly by certain gases such as ozone and water vapor. Some energy is reflected back to space by clouds and the earth's surface. Most of the radiation, however, is absorbed by the surface.Energy is transferred between the earth's surface and the atmosphere in a variety of ways, including radiation, conduction, and convection. The graphic below uses a campstove to summarize the various mechanisms of heat transfer. If you were standing next to the campstove, you would be warmed by the radiation emitted by the gas flame. A portion of the radiant energy generated by the gas flame is absorbed by the frying pan and the pot of water. By the process of conduction, this energy is transferred through the pot and pan. If you reached for the metal handle of the frying pan without using a potholder, you would burn your fingers! As the temperature of the water at the bottom of the pot increases, this layer of water moves upward and is replaced by cool water descending from above. Thus convection currents that redistribute the newly acquired energy throughout the pot are established.
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