Open vs. Closed Circuits and Inventing a Metaphor

On Tuesday (June 28) afternoon in UE2, the Toaster group (Charlene, Meg, and Michelle) presented their Energy Theater Storyboard. In the clip below, Alia describes a confusion she is having with the use of the terms "open" and "closed" as related to a circuit. Michelle invites Hunter to correct if she is wrong, and then goes on to explain what the terms mean in the context of a circuit. Akbar indicates that this explanation has helped him to better understand what is going on, and makes some hand motions that seem to be for open, for closed, and for a complete circuit. Hunter then engages Alia's original idea at the level of language, indicated that if open/close are being used with a gate metaphor, that is incompatible with the use of the same words for a circuit. At that point, Lisa asks "What about a bridge?", which I identify as inventing a new metaphor to be substituted for the gate metaphor, and there are some associated hand gestures. In this metaphor, when a bridge is "open", nothing can go through. There is general appreciation for this new metaphor, and Hunter snaps his fingers. You can see the 1 minute clip below, which comes at 2:31 minutes into UE2 110629 1315 T7:



Is this bridge metaphor, and specifically the way it invokes open and closed, useful to someone who doesn't have some physical model for how a circuit works? The open bridge image invoked by the metaphor and the hand gestures reminds me of a knife switch or actually completing a circuit with wires. If you've never manipulated a circuit or otherwise developed that mental model, does this metaphor make clear what open and closed mean? As I observed this episode, I was initially very taken with it.

Then, I thought to myself that if you didn't know about drawbridges, open and closed is the same for a bridge as it is for a gate. So I made up a story that this metaphor might be more compelling for people from the region because of the number of drawbridges in Seattle (plus Enrique and I had just watched a drawbridge go up the evening before, which is pretty wicked awesome).

But then Siri pointed out that (I'm paraphrasing here) that while it might be conceivable that an "open" drawbridge might be ok as a synonym for an "up" bridge, she wouldn't use "closed" to mean the bridge was "down". And neither would I, actually.

So I still wonder if this bridge metaphor works for someone who doesn't have a mental model of a circuit. Or of even more interest to me, would someone be able to _construct_ a mental model of a circuit consistent with a drawbridge metaphor? As Lakoff & Johnson argue, metaphors highlight the similarities between the target domains, and hide the differences. And our physics models do the same thing: highlighting where the model successfully predicts/explains the phenomenon, and hiding where it does not.

Also, I was struck by how Hunter validated Alia's idea about open vs. closed in circuits, using language and metaphor to offer an explanation for why Alia might have had that idea, in what I saw as respect for her sense-making and prior understanding and an effort to help her transform her initial understanding.