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

Teacher education: solar energy
course. A solar system adds a new dimension to efficiency studies. It can be measured, but if
energy is free, efficiency is of no consequence. Or is it? Discussion is not easy to provoke in
conventional physics lessons, but facing a question like this few classes wil remain silent. At the
end, they wil be much wiser about efficiency, cost-effectiveness and environmental impact.
A central tenet of our thinking about physics teaching is that it should be firmly based on
experience and that practical work which involves an investigation is more valuable than an
experiment which merely verifies or where the conclusion is implicit in the apparatus or the
recommended procedures. We also feel that some numerical measurement and calculation add
strength to a boy or girl’s ability to grasp physical concepts. These educational principles and
suggestions for worthwhile experiments were discussed with the student teachers. Each was
invited to choose an experiment using solar energy, to design and build the apparatus for it
and to put it in a teaching context. The sun, alas, does not always shine in England and every
student had to have back-up activities if the classes were forced to stay indoors. Some of these
were parallel experiments. The effects of radiation on coloured surfaces can be studied in sunlight
or in a laboratory and so can heating and cooling. Some activities were investigations based
on books and papers. We built up a large collection of popular articles drawn from newspapers
and magazines, and even on a bad day there was much for the school classes to do.
The reasons for the production and testing of curricular materials in solar energy are many and
can be summarized as follows. Sunlight is available almost everywhere, solar energy is in the
public eye at present and is a potential contributor to local and national energy supplies. Its
study raises scientific, technical and social questions. These can be considered at an elementary,
descriptive level, at an early stage of the study of physics and right up to advanced and graduate
levels. At any stage personal investigations can be undertaken and they can proceed to a level
of theory and analysis appropriate to the abilities of the investigators. The sun is a source of
radiant energy across a broad spectrum, -it is a source of heat and light which can substitute for
conventional sources allowing syllabuses to be extended and enriched without suffering radical
change. Numerical measurements can be made with solar apparatus and quite easy algebraic
manipulation enables heat transfer equations to be used to calculate constants and parameters
of the equipment. Solar energy is a theme par excellence with which to encourage student
teachers to develop their ideas and to make a positive offering to the educational system.
THEORY INTO PRACTICE
Student teachers need pupils to practise on and ours needed to try out their ideas with classes of
ordinary children in an ordinary school. We approached a secondary comprehensive school in
which a physics teacher was known to be an enthusiast for alternative technology. Two classes
totalling fifty children were allocated to us for one afternoon a week for ten weeks. Pupils were
aged about 14 and were of average and below average ability and motivation. Many of them were
looking forward to dropping physics for good at the end of the term. Such a class is not an easy
one to handle, and the boys and girls were taught in small groups so that no student ever had
more than half a dozen children to work with. A small group enables a student to explore
relationships and to try out different approaches without risking serious class control problems.
It also allowed time for them to assess their successes and failures with the experiments and with
their teaching. In the main, a student stayed with his own piece of equipment throughout the
term. He was able to refine his presentation continuously as different groups came to him each
week. On the few occasions when all fifty boys and girls were addressed at the same time, it was
the writer who did so.
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