We spent a lot of today using Kirchhoff's Laws (along with Ohm's Law) to make sense of circuits from the TIPERs book. The questions in TIPERs are hard and intriguing, and one student even came up with an alternative answer for a problem that I would never have come up with on my own.
Then, it was time to make sure our models for circuit elements were as precise as possible. We feel good about our model for resistance, but what about for batteries. Do they always have the same voltage, no matter what? So we tested any and all circuits we could, looking at just the voltage across the battery and the current through the battery. We had some pretty creative circuits to test this proposition.