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Viscosity Measurement: A Virtual Experiment
simulates a series of viscosity experiments. Viscosity is an important
subject in chemistry and chemical engineering. It is
important when dealing with intermolecular forces in liquids and
gases and it has enormous relevance in all technological aspects
of equipment dealing with liquids or gases. Most
university-level chemistry courses include viscosity to some extent.
Viscosity Measurement includes three virtual
experiments: an Ostwald viscometer simulator, a falling-ball
viscometer simulator, and a balance simulator for a simple
determination of the density of a liquid. The Ostwald
viscometer simulator and the balance simulator allow the student to
find out how composition and temperature influence the
density and viscosity of an ethanol-water mixture. The falling-ball
viscometer simulator allows the student to determine
experimentally the size and density of the ball required to measure
viscosity of various liquids.
Each virtual experiment includes a corresponding
theoretical section. Support from the program is sufficient to
enable the students to carry out a virtual experiment
sensibly and on their own. Preparation is not essential. Students
can use the program unsupervised, thus saving staff time and
allowing flexibility in students' time.
The design of the program interface plays a key role
in the success of a simulated experiment. Direct
manipulation has greater intuitive appeal than alternative interface
forms such as menus and has been observed to provide
performance and learning advantages (1). We tried to design an
interface that is visually attractive, is user friendly with simple and
intuitive navigation, and provides appropriate schematic
animations to clarify the principles of the laboratory procedures. The
opening screen presents the virtual experiments that can
be selected. Clicking an icon takes the student to the
appropriate section.
Viscosity Measurement allows the student to
concentrate on the experiments at hand and not on learning how to
use the program. It communicates its ideas visually with
pictures and diagrams relegating on-screen text to the minimum
required for the student to understand the presentation. A
full presentation of viscosity is reserved for the textbook,
which the computer cannot replace. It is well established
(2) that people read text on a computer screen more slowly and
with greater strain than they do text in a book. Moreover,
relatively open-ended exploration does not appear to be a
successful method of practice, because practice devised by the
learner tends, not to be well conceived and well integrated in the
students' learning path (3). For every virtual experiment we
suggest a set of coherent exercises that highlight what we
want students to know before they enter the real laboratory.
Acknowledgment
The Greek Ministry of Education and the
European Community provided financial help to create the New
Educational Technologies for the Teaching of Chemistry
course that made development of the viscosity simulator possible.
Literature Cited
- Bensebasat, I.; Todd, P. Int. J. Man-Machine Studies 1993, 38, 369-402.
- Gould, J. D.; Alfato, L.; Finn, R.; Haupt, B.; Minununo, A. Human Factors 1987,
26, 497-515.
- Wiedenbeck, S.; Zila, P. L. ACM Transactions on Computer-Human Interaction
1997, 4, 169-196.
Please refer to PDF for better views of the Ostwald viscometer.
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Citation
