Radiation and Absorption Heat Exchanges

It is known from experience that heat energy can travel from one place to another in any one of the three ways: conduction, convection or radiation.

6.2.1 Conduction

Conduction usually takes place in solids in which the tightly-held molecules pass on the heat by vibration or molecular agitation. Take, for example, the case of a long iron bar one end of which is heated. On receiving the heat energy, the molecules at the heated end which are now more agitated than those next to them on the cooler side pass on the energy through increased vibration to lower-energy molecules down the bar till the heat reaches the cooler end. Thus, conduction requires a temperature gradient and a material medium for the heat to pass through.

6.2.2 Convection

Convection, on the other hand, usually occurs in liquids and gases where the intramolecular forces are relatively less strong with the result that the molecules have greater freedom to move away from one another and carry heat from one part of the medium to another by actual physical movement. Bulk movements carrying liquid or gas from the hotter to the cooler part of the medium can occur. Thus convection also requires a temperature gradient and a material medium for the heat transfer.

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Responses

  • ulrike
    How absorption of energy causes convection in the atmosphere?
    1 month ago

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