8/17/2019 Secondary Two Science Worksheet Types of Heat Transfer 31jan2015

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Date: 31 st January 2015

1.0 Overview of Heat Transfer

Heat can be transferred from place to place, objects to objects through conduct on, con!ect on and rad at on"

Heat s a form of energy and t can only flo# or transfer from a reg on of h gher temperature $more heat% to areg on of lo#er temperature $less heat%" Hence, n summary, heat s transferred from a reg on of h gher temperature to a reg on of lo#er temperature through conduct on, con!ect on or rad at on or anycomb nat on of these 3 methods"

2.0 Conduction

&onduct on s the process of heat transfer d rectly through a mater al pr mar ly by molecular ! brat on" 'hemater al tself does not mo!e" (mag ne plac ng one end of a metal rod through a flame, the metal part cles atthat end # ll be energ sed and ! brate coll d ng # th ne ghbour ng molecules" 'hese coll s ons enable the

transfer of heat" 'he metal rod tself s not mo! ng"

3.0 Convection

&on!ect on s the process #here heat s carr ed from a reg on of h gher temperature to a reg on of lo#ertemperature through the mo!ement of a l )u d and*or gas" +hen you bo l #ater, the heated l )u d at the

bottom # ll r se and push do#n the cooler l )u d at the top" 'h s cooler l )u d # ll then reach the bottom andgets heated up and proceeds to r se" 'h s creates a cycle or con!ect on currents"

4.0 Radiation

ght from the sun s brought to earth by large amounts of ! s ble l ght #a!es as #ell as some amount ofnfra-red and ultra! olet #a!es $ recall: these waves can be found in your electromagnetic spectrum, and

light does not travel in a straight line but in a wave-like pattern %" Hence rad at on s the transfer of heat by

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8/17/2019 Secondary Two Science Worksheet Types of Heat Transfer 31jan2015

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means of electromagnet c #a!es" lectromagnet c #a!es can tra!el through !acuum, hence rad at on allo#sfor heat transfer through !acuum" !acuum n sc ent f c def n t on s a reg on of space that does not conta nmatter, "e" the space bet#een the sun and earth" Ho#e!er the sun and earth are matter" Hence the !acuum sthe empty space bet#een these t#o matters" &onduct on and con!ect on re)u re matter" Ho#e!er rad at ondoes not, th s s because electromagnet c #a!es themsel!es are not matter $they do not occupy space anddoes not ha!e mass%" ad at on does not re)u re molecular ! brat ons or c rculat on of l )u ds to transfer

heat" /lease note that rad at on can occur n !acuum and also n the presence of matter $on earth%"lectromagnet c #a!es can pass around and through matter"

5.0 Activity

abel on the blan s n the d agram belo# the most su table heat transfer method that s occurr ng from thef re and br efly e4pla n ho# each heat transfer method #or s and the med um t re)u res"

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Vacuum