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CHEMISTRY

 

simulation type dynamic simulation based on a continuous model
domain Chemistry
target group secondary education
duration 1 session of 50 minutes
model derived from general theories about acid-base equilibriums by Min van Schaick Zillesen
publisher University of Twente, Dept. of Educational Science, Div. of Educational Instrumentation
year 1986
platform Macintosh and MS-DOS
design system/ engine MacThesis (Macintosh) and Thesis (MS-DOS)
my connection educational design, software engineering, extending the model
 

CHEMISTRY

CHEMISTRY simulates titration experiments. The program is designed in order to enable students to practice the skill to determine the properties (strength, pKa, pKb) of solutions of acids and bases by titration with standardized acids or bases.

The simulated experiments can be executed very accurately because drops of acid or base can be added to the solution one after another. The speed of the chemical reactions is retarded in the simulation. For this reason it may take some time before the reaction caused by the addition of a drop of acid or base is completed. This dynamic aspect may facilitate the discrimination of the chemical reactions causing the observed phenomena.

Furthermore, time registrations of the pH, the pOH, the concentration of kation of base, the concentration of anion of acid, the concentration of non-ionized base and the concentration of non-ionized acid are provided for in the simulation. In a real laboratory this complete information can only be attained by means of expensive ion sensitive electrodes.

Boblick (1971) emphasized that students may use computer simulations of titration experiments to demonstrate their achievements in a way which is faster, safer and more efficient. He also asserted that the method of computer simulation eliminates the necessity to acquire a number of psychomotor skills in order to demonstrate the achievement of intellectual skills. Nowadays chemists seldom perform a titration manually in the way it is taught during secondary education.

The invention of advanced electronic instruments (pH meters and automatic burettes) have made the psychomotor skills acquired during secondary education, obsolete for everyday chemical applications. For this reason Boblick states that the acid-base titration during secondary chemistry teaching can no longer be important as a laboratory technique, but as a means of demonstrating the application of chemical principles. This statement implies that it is best to put the emphasis on the acquirement of intellectual skills and not on the acquirement of psychomotor skills when teaching titration during secondary education.

Compared with real titration experiments computer simulations executed with programs like CHEMISTRY may be more suitable to acquire the required intellectual skills.
 

 
 
CHEMISTRY, a dynamic simulation of a titration experiment