In the typical “cookbook” experiment comparing the radiation absorption rates of different colored surfaces, students' hands are commonly used as a measurement instrument to demonstrate that dull black and silvery surfaces are good and poor absorbers of radiation, respectively. However, college students are often skeptical about using their bare hands in this experiment because they learned in early science lessons that skin is not a reliable detector of heat transfer. Moreover, when the experiment is conducted in a school laboratory, it is often difficult for students to perceive the slight differences in heat transfer on the dull black and silvery aluminum leaves attached to their hands. Rather than replacing students' bare hands with such sophisticated apparatus as a data logger and temperature probe, I suggest using a simple (and delicious!) low-cost instrument, i.e., chocolate, which simply melts when it receives radiation.

1.
For example,
T.
Duncan
,
Exploring Physics Book Two
, 8th ed. (
John Murray
,
London
,
1976
).
2.
For example,
E.
Rogers
and
E.
Wenham
,
Revised Nuffield Physics (Pupils' Text Years 1 and 2)
, 2nd ed. (
Longman
,
London
,
1978
).
3.
P. K.
Tao
 et al.,
Living Science
, 2nd ed. (
Oxford University Press
,
Hong Kong
,
2007
).
4.
I. B.
Cohen
, “
Franklin's experiments on heat absorption as a function of color
,”
Isis
34
,
404
407
(
1943
).
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