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

String and tape experiments
String and sticky-tape experiments
R.D. EDGE.
Physics can be fun, but many students today believe that it is something which comes out of a
textbook, redolent of equations and examples divorced from reality. Part of the problem arises
because of the cost of experimental equipment, both for demonstrations and student laboratory
work. This is seen not merely in developing countries, which have no heritage of experimental
physics, but also in industrialized nations where experimental physics plays less and less of a role
in the curriculum, on the grounds that there is not enough time for it if all the subject matter is
to be covered. Although this may not be important for dedicated physics students, it is unfortunate
for those less able, in that physical concepts are more deeply embedded in our consciousness
if they can be reinforced by experiment.
Another aspect of the problem arises from the vicarious age in which we live, where children
sit glued to the television, experiencing remotely and through others rather than going out and
learning about the world first hand. Physics is an experimental science, and only by doing ‘handson’
experiments - messing about with the equipment - can you get a feel for it. One difficulty
is that most physics gear sold to schools is too expensive to allow students to work with it alone,
and to have the teacher hovering over one can be quite inhibiting.
To avoid this problem, the equipment must either be very strong, unbreakable in fact, or so
cheap it can be replaced at little cost.
The following experiments were put together to see what could be done with the simplest,
least expensive materials. The equipment can all be purchased at the nearest store - not even a
seconds watch is required (although it would be a help), nor are you exhorted to ‘go down to
the junk yard and pick up a 2000 volt transformer’ as is done in some books aiming at economy.
In spite of their simple nature, the experiments are quite meaningful, and demonstrate fundamental
physical laws in a practical way.
EQUIPMENT
The experiments involve only common rubber bands (about 7.5 cm unstretched, if available),
cellulose tape (the cheapest, clear 1 cm kind), regular paper clips, Styrofoam or paper cups,
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