The Shrewd Guess: Can a Software System Assist Students in a Hypothesis-Driven Learning for Organic Chemistry?

In a recent article in the Journal of Chemical Education, Julia Winter et al. have reported initial results indicating that Alchemie’s Mechanism App (the App) can assist a hypothesis driven approach to learning organic reaction mechanisms for students.  Many organic faculty would agree that learning reaction mechanisms with arrow pushing is one of the most difficult tasks for students taking organic chemistry.  It is often difficult or impractical to give students timely feedback as they practice writing mechanisms.  The App allows students to explore mechanisms with real time feedback.

 For each reaction mechanism (puzzle) in its library, the students are asked to solve each mechanistic step by pushing electrons with their fingers on the screen of a phone or tablet. (A web based product is also available.) The App provides immediate formative feedback by showing when a particular movement of electrons would not work and in some cases providing further hints. The students can then continue solving the puzzle.  These “error” moves are recorded, and the data of students’ attempts can be provided to instructors. They can be analyzed to see where the students are encountering difficulties.  Puzzles are designed to scaffold learning of the mechanisms.

The designers’ goals were to provide scaffolding of concepts for students while allowing for experimentation and hypothesis testing as they attempted to complete mechanisms.  There were several key questions.  Would students begin to think their way through mechanisms?  Would they try different ways of pushing the electrons and learn features of the mechanism that they didn’t know going in?  How would using the App help students write mechanisms on paper using the standard conventions? 

 Although the literature indicated that there were reasons that each question could be answered in the affirmative, an initial study was conducted at Augsburg University with six students. They were given an Aldol Condensation reaction to solve.  Each move in their attempt to solve the mechanism and use of the App was recorded.  Also, they were interviewed about their thinking throughout the attempts.  Both their “moves” in each mechanistic step and their explanations for them indicated the App did foster reasoned experimentation as they encountered roadblocks.  In the final step, the Aldol product was converted to an a,b-unsaturated ketone.  The students initially did not use the hydroxide anion as a leaving group for elimination.  They assumed it was a poor leaving group. They eventually tried it and discovered that was the only possible pathway. 

Check their article for the pedagogical foundation for the software and further details about the App.

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