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

New Trends in Physics Teaching IV
concentrates on an academic study of the laws of pure physics is an inadequate preparation for
decision-making in the real world. The study of energy can be enriched by illustrating physical
principles by reference to energy conservation and the many ways in which energy can be
manipulated to reduce the effects of shortages of fossil fuels.
In the United Kingdom, there can scarcely be a single secondary school without its ‘energy
conversion kit’. Many still have copper calorimeters with which to study heat exchanges. A11
include electricity in their courses. There is a wealth of apparatus in schools and a wealth of
teaching experience connected with energy. This is an excellent foundation on which to build,
and the fact that students in college or university themselves learned about energy using apparatus
which is still in use in school means that student and teacher have much in common and that
innovations can be made from a basis of common knowledge and experience. The other much
less specific knowledge that is shared is the knowledge of the problems of energy supply and
distribution which are bound to arise in the very near future. It was in 1973 that oil prices began
to shoot up. A look at energy supply and consumption statistics [ 1, 21 reveals discontinuities
in the graphs in or around 1973 and the Club of Rome’s [ 31 assumptions of exponential changes
are clearly false. The provision of energy for all in the most convenient and appropriate form has
suddenly become a problem and even the certainties of regular growth and decay have been
eroded. These factors combine to provide an almost perfect basis for curriculum innovation.
There is a need for materials which wil help children to become aware of energy issues. There
is apparatus available for the study of energy. Teachers, students and lecturers alike understand
the laws of energy conversion. The innovation can be an extension of existing practice and needs
no radical reshaping of syllabuses or examinations. Studies can be organized in problem form
and answers can be offered following experimental work or study of resource material. The rest
of this article is built around a teacher training programme which grew from an awareness that
the study of energy in school can be extended beyond conventional syllabus material. A dozen
graduate students (engineers and physicists) were invited to prepare teaching materials and to
try them out in school. A year later experienced teachers attended in-service courses to consider
and extend the students’ ideas and to build some apparatus for their schools. Prototype apparatus
was also built in the university and issued to a number of schools which were asked to comment
on the strengths and weaknesses of the equipment.
SOLAR ENERGY
The students involved in the first development work were attending a one-year course leading to
a Postgraduate Certificate in Education at Southampton University. The possession of a degree
meant that their knowledge of physics was sound and that they were technically well-equipped
to design and handle apparatus. At the time, solar heaters were b,eginning to appear on rooftops
and studies were being published evaluating performance and cost. Solar heaters heat water;
traditionally, water in school physics is heated in beakers or calorimeters but the usual ‘heat lost’
and ‘heat gained’ calculations can be carried out as easily with solar heated water as with water
heated by a Bunsen burner. Here was a way of covering an important concept in a context which
had immediate significance for the boys and girls. Similarly concave mirrors appear in many
syllabuses. We used big ones in the sunshine instead of tiny ones in a laboratory. Impedance
matching of electrical supplies and loads is an important topic at more advanced levels. We used
solar cells, not batteries; they are more interesting and their characteristics change with incident
radiation. Questions can be asked about solar cells which lead to worthwhile practical investigations
and which call for quite a depth of understanding to answer convincingly. The concept of
efficiency is fundamental in the thinking of most engineers and appears in every school physics
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