Ah-Ha

During the molecular modeling activity I have described before (Model Students, Molecular Mechanics), there is a little moment of discovery. The students make and draw four constitutional isomers with molecular formula C2H5NO2 to answer questions 1 through 9. All the constitutional isomers they have made so far have a double bond. On question 10 they are asked to make a molecular model with same molecular formula without a double bond. This question presents a challenge for most students. Making a structure without a double bond seems almost counter-intuitive at this point since every structure they have seen with this molecular formula so far has a double bond. As you may well imaging there is a variety of responses. If the answer does not become evident after a minute or so, some students get frustrated. A few skip the question. Some write down a structure that has no double bond that does not fulfill the criteria of “every hole filled.” Some ask the instructor what to do. What should the instructor do? How much can (should) a student be “guided by the instructor” to the correct answer? It seems to me that it is important the student struggle through the question to find an answer that they know is correct. I am almost sure that this is the pedagogically sound method. Presenting students with challenges is part of the responsibility of an instructor, but it is not without risk. Student frustration over not being able to solve a problem in what seems, to the student, a reasonable amount of time is manifested in various ways. Teaching lab can get a little dangerous at times.