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<br />. <br />.".. . .a 0 <br />......:. :.. ". :..0. <br />. ...... .:.. ...... ..... <br /> <br />EvA <br /> <br />.. .... ..." '.0 0.... <br />"'0 .. '. .. '. ..0... '.. <br />.:...... ..':0, 00.;' ::'0... ...: :::. ..............: .::.' <br />.. ..0 ., ... '.. ..' . . ...... . ., . . ~ '. '." . '.. ... <br />'0: . .~.: ,"....0... t .. 0" .. .. .. _:',' .,. ..... . . ." '. :.': 0": '..... .;. '0 .. <br />. ..... 00' . ...... ., 0" 0..0', ..' "" 00 ...... <br />P.,RATI'UN':; <br /> <br />{{({ {ff 1m {f>; <br />()()0CJfl <br />0- <br />\ . <br /> <br /> <br /> <br />Warm a spot on a blackboard or slate <br />with a candle or sunlight. Using a <br />sponge, place waler spots 01 equal size <br />on this warm area and one a cool one. <br />How long did II take the warmed spot to <br />disappear? <br /> <br />The cool one? <br /> <br />Why? <br /> <br />The warmed spot will evaporate faster <br />than the cool one. The effect is the same <br />as boiling warer. with heated molecules <br />moving faster and escaping as vapor into <br />rheai,. <br /> <br />{{2()(;2Cifi <br /> <br /> <br />With a mOrst sponge or cloth, make <br />spots 01 equal size on a cool blackboard <br />some distance apart. Fan one spot and <br />let the other evaporate on its own. <br />WhiCh one evaporated first? <br /> <br />The fanned spat. <br /> <br />Why? <br />Fanning wifl increase the volume of air com. <br />ing in contact with the water and more <br />vapor will be absorbed. <br />Where have you seen the same thing <br />happen in nature? <br /> <br />Puddles on a sidewalk demonstrate the <br />effects of both wind and heat on <br />~aporation. <br /> <br />-14- <br /> <br /> <br /> <br /><3'~ <br /> <br />TYP <br /> <br /> <br />Pour one cup 01 waler into <br />each 01 3 one lb coHee cans <br />Iilled with dlllerent types of <br />soil. clay, sand and a good <br />loam or potting soil. <br />Weigh each can daily for a <br />week. <br />What happened? <br />The Cilns got lighter as the wa~ <br />~aporarea from the wil. <br /> <br />Why did one can getliqhler <br />faster? <br /> <br />The can of sand will lose its <br />V'r18ter ro evaporation quicker <br />since the sand does not ab. <br />51)rb the water as well. <br />