In the teaching of physics at upper secondary school level (K10–K12), the students are
generally taught to solve problems analytically, i.e. using the dynamics describing a system
(typically in the form of differential equations) to compute its evolution in time, e.g. the
motion of a body along a straight line or in a plane. This reduces the scope of problems,
i.e. the kind of problems that are within students' capabilities. To make the tasks
mathematically solvable, one is restricted to very idealized situations; more realistic
problems are too difficult (or even impossible) to handle analytically with the mathematical
abilities that may be expected from students at this level. For instance, ordinary ballistic
trajectories under the action of gravity, when air resistance is included, have been 'out of
reach'; in school textbooks such trajectories are generally assumed to take place
in a vacuum. Another example is that according to Newton's law of universal
gravitation satellites will in general move around a large central body in elliptical
orbits, but the students can only deal with the special case where the orbit is
circular, thus precluding (for example) a verification and discussion of Kepler's
laws. It is shown that standard spreadsheet software offers a tool that can handle
many such realistic situations in a uniform way, and display the results both
numerically and graphically on a computer screen, quite independently of whether the
formal description of the physical system itself is 'mathematically tractable'.
The method employed, which is readily accessible to high school students, is
to perform a numerical integration of the equations of motion, exploiting the
spreadsheet's capability of successive iterations. The software is used to model and study
motion of bodies in external force fields; specifically, ballistic trajectories in a
homogeneous gravity field with air resistance and satellite motion in a centrally
symmetric gravitational field. The article reports briefly on a study of the use of
computers in the teaching of physics at K12 level in Norway, as part of an EU
research project (for details, see the end of the article). It is demonstrated how the
simulation software (the spreadsheet) is implemented in practice, for the systems that
have been studied, and various responses of the students and teachers to this
new and unfamiliar method for solving problems in physics are discussed. Some
perspectives on the future of physics teaching at secondary school level are discussed.
