Working at George Mason University (GMU), even as an adjunct microbiology lab teacher, proved to be very different from NVCC. The course content was strictly regulated, there were weekly prep sessions, the methods of evaluation were standardized, and, oddly enough, the vast majority of the students were female.
I found myself giving lab quizzes for the first time. These were a real eye-opener since I saw how little the lab students really understood.
I’d found that it was best to keep on the move during lab so I would be accessible to my students and they could ask me any questions as they came up.
Doing her Best
My eye was caught by a young lady, Deepti. In attempting to transfer a colony of bacteria from one plate to another, she heated the wire loop used to pick up bacteria to red heat and placed it on the colony. She hadn’t waited for it to cool, so there was a sizzling sound, and the agar growth medium spattered. Deepti blushed as she noticed me watching. She then reheated the loop, but remembering that it should be allowed to cool, she blew on it before applying it to the new agar, closed the plate, and placed it in the incubator.
Not Good Enough
“Deepti, do you think anything will grow on that plate?”
“Of course, but it’ll take 48 hours.”
“Lead me through what you did.”
“Well, I heated the loop so it would be sterile.”
“Good,” I encouraged her, “and then what?”
“I picked up a colony from the plate.”
“Did you make a mistake?”
She hesitated, but remembered that I’d been watching. “Well, yes, I forgot to let the loop cool, so the agar spattered.”
“Right, and what do you think that might have done to your bacteria?”
Deepti thought for a while, “I guess it might have killed them.”
I smiled, “I think you’re right. Now, what did you do next?”
Sterility not Guaranteed
“I heated the loop in case it had become contaminated.”
“Yes, and if there were any live bacteria on it, what happened to them?”
“They died?” she said, looking a bit worried.
“Yes, so now you have a sterile loop. Then, what did you do?”
“Well, I learned from my mistake and blew on the loop to cool it before putting it onto the new plate.”
“So, do you think it was still sterile after you blew on it?”
Color slowly seeped up Deepti’s face, “I hadn’t thought of that.”
“Okay, so if you get growth on that plate, will it be what you wanted?”
Deepti shook her head, “No, I killed the bacteria I want and inoculated the plate with contaminants from my breath.” Deepti repeated the procedure, this time without mistakes.
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