This year, the introductory lab assignment I gave my chemistry students was to bake a batch of cookies without using a recipe. I’m pleased with how the assignment worked out, so I thought I’d post about it here.
The assignment served several purposes:
- introduce the kids to writing up experiments in a lab notebook and filling out the “student” column in my lab experiment rubric sheet
- introduce the kids to the idea of designing their own experiments, without using someone else’s procedure
- get the kids used to the idea that experiments don’t always work, and that’s OK
- get the kids used to the idea that in science, there generally isn’t one “right” way to do things
- introduce the kids to the idea of talking informally about their experiments to their peers
The students in each of my classes brought in their cookies today. I’m pleased to report that all of them did something “interesting”–not one of them used a recipe verbatim without modifications. Many of the kids used extra butter, which resulted in flat, crunchy, buttery-tasting cookies. Some of them added extra liquid, and (to their surprise) ended up with cake or muffins. A few used too much baking soda, resulting in cookies that were bitter enough to be practically inedible. (This was in my AP Chemistry class, so I talked with them about using lemon juice to neutralize the excess base and add an interesting citrus flavor.) The most unusual of the cookies were made with ingredients like Mountain Dew and Cocoa Krispies.
I kept my promise, and tasted each student’s efforts, no matter how badly the student claimed the cookies had come out. My one rule (other than the requirement that they not use a recipe) was that they weren’t allowed to use non-food ingredients, and that they were to use only ingredients that would plausibly taste good in cookies. (I told them the squid pie story as an example of what not to do.)
I had expected that this assignment would take a few years of refinement before I was happy with it, but it worked so well on the first try that I felt compelled to post it.
