I picked the “Analyzing Data from Multiple Files” module of the Python novice training. The students have just seen how to manipulate Python lists in the previous module, and I tried to call back to that knowledge in the discussion of glob.glob() and what it returns.
I also thought it was a bit smaller in scope than my last teaching demo, which was fitting for the three minute restriction. I found myself running out of material at three minutes, not wanting to launch into the next section (looping and plotting data sets) with only thirty seconds or so left.
Watching myself made me think of about a million things I could do better! Specifically, tying things back to lists (and just improving the internal coherence of my explanation) would be something to work on with this material.