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Heat Loss in Penguins or Test-tubes


If penguins are out of season or unavailable, test-tubes may be substituted
.


Materials

8 test-tubes or boiling tubes
stop clock
2 thermometers (-10 to 110 C)
elastic band
beaker to hold tubes
test-tube rack
measuring cylinder

container of hot water

Method

(when working in pairs, each pupil should do half of each procedure, and duplicate measurements independently)

1) Fill up one tube with cold water from the tap and use the measuring cylinder to work out its volume. Record this value, then tip the cold water away.
2) As accurately as you can, measure half the volume you have determined above of hot water into each of the 8 tubes.
3) Put one tube by itself, and the remaining 7 tubes into a bundle, held by the band.
4) Take the temperature of the water in the single test-tube, and write it down.
5) Take the temperature of the water in the centre test-tube of the bundle, and write it down.
6) Repeat stages 4 and 5 every 3 minutes for, say 24 minutes.
7) Record results in a tabular and a linear graph form. Think independently about the best way to do this.

Interpretation

(single word answers are not sufficient)

8) What conclusions can be drawn from your results concerning surface area, volume and temperature loss?
9) How may this be related to simple animals and many-celled animals?
10) Can this be used to explain the behaviour of male penguins which huddle together as they incubate their eggs?
11) Is this biology or physics? Are there any other everyday applications to this principle?
12) Comment intelligently on the design of the experiment.

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