1. Global Description

The simulation program xyZET offers the possibility to visualize animated objects in 3d and to simulate attractive and repulsive forces. All didactically meaningful parameters are accessible for interactive variation. The program is intended to support the presentation of concepts during lectures and to form the base for the arrangement of exercise material to be worked at by individual students.

2. Scientific Content - Important Features

The program covers a series of basic concepts of mechanics and electricity which form part of each introductory course in physics.

The main concepts are:

Besides the introductory level, some more advanced topics from solid state physics (lattice symmetry, van der Waals forces) and relativity (relativistic addition of velocities, retarded potential) are included.

3. Didactical Approach

The standard approach in introductory courses in physics is based on demonstrations of experiments and direct comparison of the results with abstract mathematical expressions. This is accompanied by labwork, often not synchronized in sequence and time.

The simulation presented here as a new medium or tool for teaching, offers an intermediate step between real experiments and abstraction. By shifting all the mathematical overload towards the machine, the results can first be presented in visualised form, serving as pre-organizer for the learner to build a knowledge base of qualitative concepts.

The need for mathematical tools and integration of qualitative and quantitative methods for an effective reduction of complexity can be demonstrated convincingly.

4. Implementation

In its basic form the program presents a cube which can be rotated, zoomed in and out under various perspectives. The simplest use of this \xe3 world"is to load prepared files to present any kind of 3-dimensional object in animation (rotation).

As a more interactive use, small geometrically simple objects can be placed at any position with variable parameters like, coordinates, velocity, mass, charge. Forces of different kind like gravitation, Coulomb, forces of springs of different length (pull, push, both) can be set and monitored. The centre of mass can be indicated as well as the kinetic and potential energy.

This arrangement offers a variety of experiments like inclined throw, pendulum, collision, elastic deformation, vibration, waves, planetarian motion, a.o.

The effect of Coulomb attraction and repulsion between particles, enclosed in different parts of the volume, can be shown, together with field lines or equipotential surfaces in animation.

The model used is based on Newtons 2nd law by computing the forces (acceleration) for each particle, using finite differences to find the velocity and the displacement.

A high resolution screen is indispensable to give a satisfying presentation within a "3d-world" in animation. The influence of many particles (many = > 50) is necessary to demonstrate any effect due to bulk material. The computational power needed for this task is offered today only by high powered workstations.

A documentation with a full description of the functionality of the user interface, the didactical principles involved and a list of proposed student activities is being developed and will be available during spring 1994.

5. Target group

The simulation program should serve during lectures, mostly on Sec. II and university level and in parallel with experiments. It should also be integrated into labwork where additional support material would have to be provided by the teacher. It may serve as an environment for exploration and practice for the motivated individual learner.

6. Evaluation

Evaluation has been carried out during development in fragmented form and only with small groups.

After finishing the documentation the program will be offered to selected teachers for tryout. A controlled evaluation study will be carried out during 1994.

It is expected that teachers will state a more efficient and satisfying experience in making physics more understandable and in raising interest in science.

It is expected to find better results in learning when testing students in relation to understanding of concepts and the meaning of mathematical tools.

The Simulation Program "xyZET"

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