New trends in physics teaching, v.4; The ... - unesdoc - Unesco

New Trends in Physics Teaching IV
such a basic matter as the First Law. Henry Bent, in his delightful book ‘The Second Law’’
points out that ‘most people believe this law firmly; mathematicians because they believe it is a
fact of observation; observers because they believe it is a theorem of mathematics; philosophers
because they believq, it is intellectually satisfying, or because they believe no inference based
upon it has ever been proven false, or because they believe new forms of energy can always be
invented to make it true. A few neither believe nor disbelieve it; these people maintain that the
First Law is a procedure for book-keeping energy changes, and about book-keeping procedures
it should be asked, not are they true or false, but are they useful?’
In recent years, as energy has assumed greater and greater importance in the world at large
with real shortages, high costs and a barrage of propaganda, any separation of energy teaching in
physics courses in schools from the real world has become a real danger to understanding. It is
clear from the contributions which follow, that this point is thoroughly accepted by forwardlooking
teachers the world over.
As citizens, we wish our students to appreciate the following things about energy, whatever
else they leam about it in formal terms:
1. Energy gets things done - it grows crops, drives machines, lifts loads, heats our homes,
cooks our food, operates communication systems, keeps us alive and so on.
2. Energy costs money (fuels, foods and the costs hidden in their production).
3. Energy continually shifts from form to form - and in so doing may be applied to useful
(and not so useful) human purposes.
4. Energy ultimately derives either from the Sun or the nucleus.
5. Energy is ‘conserved’ in the scientific sense; but, in the end, it is degraded to the form we
call ‘heat’- and, unless at sufficiently high temperature, is virtually useless.
Nothing there conflicts with the more formal approach we may wish to adopt with older
students in the secondary schools. Indeed, that approach wil then be recognized for what it is -
-a refinement of the intuitive view providing a necessary sense of proportion.
These older students are exposed to a further trend - that towards a statistical view of heat
processes. Teachers attempting to follow this trend wil find the comparative study of some of
these approaches which has been prepared by JM. Ogbom especially valuable. It is therefore
included at the end of this part.
1. Henry A. Bent, The Second Law: An Introduction to Classical and Statistical Thermodynamics, New York, Oxford University
Press, 1965.
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