Embed Size (px)
Citation preview
8/20/2019 Gr 8 Heat Transfer
http://slidepdf.com/reader/full/gr-8-heat-transfer 1/4
Name: ........................................ Index No: ................... Gr: 8 Transfer of Heat Worksheet****************************************************************************I Choose and underline the correct answer
1 A cup of hot tea is left in the same room as a bo l of ice!cream. What is likel" to
happen to both of them after some time# if the t o ob$ects are both placed on the dinin%
table&
A The tea becomes as cold as the ice!cream.B The ice!cream becomes armer than the tea.C The tea cools to room temperature# the ice!cream melts and arms to room temperature.D The tea becomes colder than before# but not as cold as the air in the room.
2 When a piece of plastic is armed on one end# the heated plastic molecules transfer thermal ener%" b"
A streamin% from the heated end to the colder end.B 'ibratin% more 'i%orousl" and knockin% into their nei%hbours.C radiatin% infra!red ra"s to the colder end.D mo'in% to the less dense re%ion.
3 (in (in steps on the carpeted floor and notices that it feels armer than the marblefloor. This is becauseA the carpet is darker in colour than the marble floor.B there are la"ers of trapped air bet een the fibres of the carpet.C she has a 'er" lo metabolic rate.D the marble floor is hite and shin" so it is a bad absorber.
4 The dia%ram sho s a metal pot containin% some ater hich is placed on a hot plate.
The metal base is heated up )uickl" mainl" b"
A mo'ement of electrons. B Bmo'ement of solid molecules.
C molecular 'ibration. D Demission of infra!red radiation.
8/20/2019 Gr 8 Heat Transfer
http://slidepdf.com/reader/full/gr-8-heat-transfer 2/4
II Answer the following
+xplain h":
,i- a cookin% pot ma" ha'e a copper base and a plastic handle
...................................................................................................................................................
................................................................................................................................................... ,ii- earin% a fe la"ers of T!shirt can keep "ou arm durin% cold ni%hts.
...................................................................................................................................................
...................................................................................................................................................
/ In an in'esti%ation to compare the thermal conducti'it" of four metals# 0o" coats the fourdifferent metal rods ith a thin la"er of ax# and attaches each rod to a container of boilin% ater.
,a- ,i- What can "ou deduce from 0o"1s in'esti%ation&
...................................................................................................................................................
................................................................................................................................................... ,ii- +xplain "our ans er
...................................................................................................................................................
................................................................................................................................................... ,b- 2tate hat 0o" should do to ensure a fair test in her in'esti%ation
...................................................................................................................................................
...................................................................................................................................................
8/20/2019 Gr 8 Heat Transfer
http://slidepdf.com/reader/full/gr-8-heat-transfer 3/4
3 +xplain h":
,i- the heatin% element of the electric kettle is placed at the bottom
................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ,ii- the free4er compartment in a refri%erator is placed on top.
................................................................................................................................................... ...................................................................................................................................................
................................................................................................................................................... ..................................................................................................................................................
8/20/2019 Gr 8 Heat Transfer
http://slidepdf.com/reader/full/gr-8-heat-transfer 4/4
5 2en% sets up the apparatus as sho n in the dia%ram belo to in'esti%ate thermal ener%"transfer.
,a- 2en% ould like to %ather reliable data on heat ener%" transfer throu%h this in'esti%ation.
2tate one action he can take to ensure that the experiment is fair.
...................................................................................................................................................
................................................................................................................................................... ,b- 2tate and explain 2en%1s obser'ation hen he li%hts the 6unsen flame.
...................................................................................................................................................
................................................................................................................................................... 7 The same amount of ater is poured into each of the t o containers# A and 6# and left
under the sun for a fe da"s. It as later obser'ed that the ater in container A hasdisappeared and the ater in container 6 has become lesser.
,a- What process has taken place in the abo'e acti'it"&
...................................................................................................................................................
,b- Wh" has the ater in container A dried faster than the ater in container 6& ...................................................................................................................................................
