BCCE: Day 1 Recap

By | July 30, 2012

While not always in realtime (thank you Google Docs offline!), you can follow and ask questions/post comments on my notes from the BCCE conference here.

Day 1 was short, but pretty good. While all of the sessions I attended didn’t fit my needs, some were really good. I’ll only discuss one today.

The end of cookbook labs: Student-designed procedures: This talk was by Dr. Laura Lanni who has experience teaching both undergraduate chemistry and AP chemistry, so her perspective was very relevant for me. In her experience, when students are given a procedure, they tend to follow it blindly, finish it quickly, and ultimately forget what the purpose of the experiment was. In switching to student-designed procedures (DIY), students are forced to think about what they’re doing, and why they’re doing it.

She begins with a seemingly simple, and notably non-chemistry activity she asks her students to tell her how to make a Peanut Butter and Jelly Sandwich.  she observes that students are very eager to just DO IT, rather than thinking about the process. Once the students realize that “put the peanut butter on one slice and the jelly on another slice” doesn’t yield their desired results (picture a jar of peanut butter and a jar of jelly on two slices of bread), they begin to focus on the steps of the process more closely.

Rather than presenting a prompt and leaving students to individually tackle with the tasks, her DIY approach is very discussion based. An exemplary example involved a lab that I generally dread due to the mindless procedure-following: Determination of the Equilibrium Constant of an Iron(III) Thiocyanate Reaction. The outcome of the lab depends heavily on solution preparation, and an understanding of how to use the data once its collected. There are so many steps, that students quickly lose sight of what they’re doing, and perhaps never really understand why they’re doing it. Great numerical results can often hide the fact that their conceptual understanding of equilibrium is lacking.

Dr. Lanni presents this lab as a DIY experiment. While students impulsivity doesn’t necessarily decrease over the course of the year (“Let’s just mix X and Y”), through discussion, students are able to, through discussion, move beyond using equal concentrations of each reactant to thinking about what information they actually need to obtain the equilibrium concentration. Let’s start with 0.1 M of each reactant. How does this get us to Keq? Is it an initial or an equilibrium concentration? Don’t we need at least one equilibrium concentration to find Keq? How can we find equilibrium concentration? We’ve used titration to find concentration, will that work? Damn you Le Châtelier! What other tools do we have to determine concentration? (Surprise! Beer’s law). Students can map out their ICE table, along with an experimental plan, and obtain their data with more of a firm understanding of what they’re doing and why they’re doing it. And pretty soon, students will notice that their results are consistent with other groups (Hey! The equilibrium constant is… constant!).

Dr. Lanni’s example of DIY with this equilibrium lab definitely inspired me to rethink how I approach this lab. Is it really necessary to find the Keq for a half-dozen different concentration ratios? Is it essential that students obtain their own FeSCN calibration curve? (or is it possible to sneak this into a separate Beer’s law lab?). If not a fully DIY approach, in what ways can I better assess during the lab that students are not missing the underlying concepts of the lab?

On to Day 2…

 

 

 

 

 


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