Digest This

My small biology class (two boys) left the world of prokaryotes and jumped to animal form and function, although given my bent, it’s largely human anatomy and physiology.  This week, the digestive system. I love the digestive system.  Basically, we all have a tube running through us that isn’t us.  We’re like a stack of bagels, with the holes lined up to be our digestive system.  Sure, we secrete enzymes and the like and absorb nutrients, but much of what comes in the top goes out the other end, never becoming part of us.

It’s a pretty easy system to teach due to our intimate personal experience with it.  We all eat, we all excrete, and we’ve all had the system go wrong on us.  Experimenting with it, however, presents a bit more challenge.  We’d already chewed a bland cracker for long enough to taste the starch break into sugars thanks to amylase (a digestive enzyme secreted in the mouth).  After they’d read on the system, and I’d lectured on it a bit, I set them to design labs to explore amylase activity and ideal conditions for pepsin activity, (an enzyme that breaks down proteins in the stomach).  Each boy took a subject, and, after some research on their particular enzyme, asked a question to answer with an experiment of his own design.

Despite some initial anxiety from my own child (that blank page gets him every time), the boys did a brilliant job.  I’m quite a fan of inquiry learning, although I can easily get lazy and give the kids cookbook labs — instructions of what to do and why you’re doing it, outcome predictable.  Cookbook labs have their place, especially to teach a specific laboratory skill or to work with potentially dangerous materials.  I’m all for creative thinking, but safety comes first.   But one of the most important reasons to teach science is to foster scientific thinking.  “Real” scientists study the world, ask questions, and then experiment.  The results of the experiment lead to more questions and more experimenting.  Scientific knowledge occurs in context, not in a vacuum.  When I read, I forget; what I do, I remember, and all that.

I’m eager to hear their lab presentations next week.  They’re terrific boys with amazing minds and boundless energy.  Some of that energy found its way to biology on Wednesday, and the minds followed.  Gotta love it.

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