A. Hämäläinen: An open microcomputer-based laboratory system for perceptional experimentality, University of Helsinki, 1998, xiv, 238 p, University of Helsinki, Report Series in Physics, HU-P-D70, ISSN 0356-0961, ISBN 951-45-8182-2.

Classification (INSPEC): A0140G, A0150H, A0150M, A0650D, A0650M

Keywords (INSPEC): computer aided instruction, computer instrumentation, education, demonstrations, student laboratory apparatus


A computer, which is equipped with hardware for acquiring data about the properties of a physical system, and programs for processing that data, is a powerful tool for physics research and instruction. There is strong evidence that utilizing microcomputer-based laboratories (MBLs) in instruction can lead to significantly improved learning and retention. Several commercial MBL packages, including sensors, data acquisition units and software, are currently available.

The perceptional approach is a method for physics instruction, developed at the Department of Physics, University of Helsinki. Its main arguments are that the meanings of the concepts must be learnt before their formal definitions and adoption, and that learning and research are fundamentally similar concept formation processes. While the perceptional approach has some unique emphases, at a general level, it is in concordance with other approaches of science instruction based on the constructivist philosophy, which states that all human knowledge is constructed by individual minds interpreting their own sensory perceptions in an active and cumulative fashion.

Applying the perceptional approach to physics instruction requires the ability to perform a wide variety of quantitative experiments, either as studentsí laboratory exercises or lecture demonstrations, and to process their results. Especially, quantities are found out as invariances. In a physical system, the value of a quantity is found to depend on the value of another quantity in an invariant manner. The dependency is recognized graphically; this may require the changing of variables, so as to end up with a linear dependency, which can be identified visually. The slope of the graph is an invariance, and it is defined as a new quantity that describes a property of the phenomenon that is studied. The law that states the dependency becomes the defining law of the quantity; the experiment, added to the definition of the slope of the graph, becomes the first means of measuring the value of the new variable.

MBL tools are essential for performing the experiments required by the perceptional approach. In studentís laboratory exercises, they reduce the routine work and leave more time for the actual learning. In lecture demonstrations, they make it possible to perform the experiments in the tight time limits.

When the perceptional approach was first applied to the lecture demonstrations at the University of Helsinki, Department of Physics, it was found that the commercial MBL packages available had severe shortcomings. In my licentiate thesis, I tested three commercial MBL packages from this standpoint. As a result, a set of requirements was found that the perceptional approach places on MBL systems.

The next step was to find out, if it could be possible to build a prototype of a MBL system that would fulfil these requirements. The effort to achieve this is described in this thesis. A secondary goal is to thoroughly describe technical aspects of a computerized measurement system from the standpoint of educational use.

The prototype was built using mostly commercial sensors and data acquisition units. The software was written with a visual programming language, designed for building industrial testing and instrumentation applications. The prototype was designed to be open and non-commercial. The software is released into the public domain.

The prototype system was developed and tested with a set of demonstrations of various topics in the Finnish high school physics curriculum, which were implemented according to the perceptional approach. Limited usability tests were performed with the students of the physics teacher education program, and the teachers in a complementary education project. Studying the usability with a broader user base, or testing the effects on learning, were considered to be a matter of continuation of this thesis.

The prototype was improved, until it could perform the test demonstrations. It was found to meet the formulated requirements quite well, although not fully. It was also found that a visual programming language for instrumentation might have also wider use in science education. Visual programming can be used not only for measurement, but also for the tasks for which the electronic spreadsheet has been found to be well suited, like processing any numerical data, graphing and simple simulations.

The public domain programs of the prototype and the free run-time environment required for running them can be downloaded via Internet (see Appendix 3). The prototype can be utilized after acquiring the commercial hardware. The software may be studied and developed further by obtaining the commercial software development environment.