engleski

The Candle, Aletrnative Concepts and Chemistry Teaching

A cross-age study was performed with the intention to examine alternative concepts that were developed by Croatian students and teachers in explaining the results of a experiment and describing observed chemical change through the concept of a chemical equation. The experiment in question was the simple and well-known experiment with the candle burning under a glass vessel. A extensive analysis of available text-books was also performed, that indicated that this experiment is often used misleadingly in teaching. An example of this is using the experiment to demonstrate the volume-percentage of the oxygen in a sample of air. A series of carefully conducted experiments was performed that have unambiguously shown that the results of the experiment are very dependent on the experimental procedure and can not be used with this purpose. This was clearly demonstrated by conducting the experiment repeatedly in a closed system.1, 2, 3 If properly conducted, the burning candle experiment should definitively be used in teaching Chemistry at the introductory level, because of its extremely high educational value. Through this experiment, students are faced with a real and interdisciplinary scientific problem. To solve the problem, they must use the knowledge of physical and chemical concepts they have acquired so far and train themselves in scientific method.

cross-age study; alternative concepts; burning candle

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