#scichat sticky electrostatics

first, the good news.

A few days ago I was leading my physics students through an activity in the lab manual on static electricity.  In the past, students who have not had chemistry had a hard time understanding the similarities between chemical bonds and electrical attractions. Because the discussion section of the activity has a fair amount of detail about that, I've usually started that activity by asking students to work together to summarize the discussion paragraphs.

this time, it wasn't going so well, and very suddenly in class I realized why.

The discussion section of the lab sheet starts with an assumption on the part of the lab manual writers:  they assume most people think friction, and friction alone, is the source of static electricity.  And I can see why they might make that assumption:  probably the most common example of static electricity we all experience is something like shuffling your feet against a carpet and then feeling a shock when you touch a doorknob.  But I had missed one crucial step.  I hadn't checked to see if my students agreed with that assumption, or even if that was indeed a common experience for them.

I changed the course of the discussion midstream.  I pointed out the assumption the authors were making, and asked if they thought it was a valid assumption.  I polled the class with a thumbs up/down option and found they were split 50/50.  "Ok then," I said, "if that's not a valid assumption, then what did you think was the cause of static electricity when you walked in this room today?"

Now the discussion took off in the really productive way!  We compared ideas and found that most students did not assume friction alone was the source of static electricity.  They knew that the materials involved had something to do with it, but they weren't sure which materials made a difference or why.  Now we had their natural curiosity activated, connected by an analysis of their own prior experiences.  The rest of the lab activity went beautifully!

unfortunately, I've got some prime pseudoeducation going on in my other classes.  more on that later!

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