Watching the Light Bulbs Turn On

Like many teachers, I live for those moments when I can watch a light bulb go on in one of my students’ heads. When it happens, even once, it can make my entire day.

My organic chemistry class has been discussing resonance stabilization. They’ve already studied SN1, SN2, and NACC (nucleophilic attack at carbonyl carbon) reactions. After having them do a problem set where they moved bonds around to stabilize charges, I drew the following:

on the board and paused for effect. The light bulbs started coming on, one student at a time, all around the classroom.

“Oh. I get it!”
“Huh? Oh! Yeah!”
“I see it too.”
“I don’t get it. Wait a minute…does it…? Oh!”

The light bulbs kept popping, and within about 60 seconds the entire class had figured out that the resonance stabilization enabled a reaction to happen (via an SN1 pathway) that couldn’t have happened otherwise (because primary halides can normally react only via SN2), and understood exactly how the exercise they had just done fit into it.

It’s impossible to plan moments like that, but when they happen to a teacher, it’s like winning the lottery.

About Mr. Bigler

Physics teacher at Lynn English High School in Lynn, MA. Proud father of two daughters. Violist & morris dancer.
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