<script>on mouseUpput the short name of this card into xTempput char 2 to 6 of xTemp & ".mov" into Movie--put Movieif Movie is not empty then-- put "Animations:" & Movie into pMoviePlayMovieLooped Movie,"Animations:"end ifend mouseUp</script>
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<text><span class="style10">hermodynamics (6 of 6)Latent heat</span><span class="style7">When heat flows between a body and its surroundings there is usually a change in the temperature of the body, as well as changes in internal energies. This is not so when a change of form occurs, as from solid to liquid or from liquid to gas. This is called a </span><span class="style26">phase change</span><span class="style7"> and involves a change in the internal energy of the body only.The amount of heat needed to make the change of phase is called the </span><span class="style26">hidden</span><span class="style7"> or </span><span class="style26">latent heat</span><span class="style7">. To change water at 100 deg C (212 deg F) to water vapor requires nearly seven times as much heat (</span><span class="style26">latent heat of vaporization</span><span class="style7">) as to change ice to water (</span><span class="style26">latent heat of fusion</span><span class="style7">). This varies for water at different temperatures - more heat is required to change it to water vapor at 80 deg C (176 deg F), less at 110 deg C (230 deg F). In each case the attractive forces binding the water molecules together must be loosened or broken.Latent heat has an important effect on climate. A similar cycle takes place in a heat pump or refrigerator.ASHEAT TRANSFER CONDUCTIONHeat conduction occurs when kinetic and molecular energy is passed from one molecule to another. Metals are good conductors of heat because of electrons that transport energy through the material. Air is a poor conductor in comparison. Thus a string vest keeps its wearer warm by trapping air and so preventing the conduction of heat outwards from the body.CONVECTIONHeat convection results from the motion of the heated substance. Warm air is less dense than cold air and so, according to Archimedes' principle, it rises. Convection is the main mechanism for mixing the atmosphere and diluting pollutants emitted into the air.RADIATIONRadiation is the third process for heat transfer. All bodies radiate energy in the form of electromagnetic waves. This radiation may pass across a vacuum, and thus the Earth receives energy radiated from the Sun. A body remains at a constant temperature when it both radiates and receives energy at the same rate.</span></text>
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<text><span class="style10">. Latent heat.</span><span class="style7"> The effect of latent heat on climate.</span></text>
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<text>ΓÇó MOTION AND FORCEΓÇó FORCES AFFECTING SOLIDS AND FLUIDSΓÇó THE HISTORY OF SCIENCEΓÇó ENERGYΓÇó ENGINES</text>
