On teaching lab skills…

by Jim Caryl

[ratings]

I HAVE been applying for jobs in recent weeks, far and wide. The flavour of jobs that I’ve been looking at are teaching positions, some lectureships, and others senior tutor positions. One of the aspects of my jobs that I’ve enjoyed over the years is teaching people, especially teaching people how to do molecular cloning and protein biochemistry. I’ve looked after many final year project students, summer students, grad students and junior postdocs over the years, and enjoyed access to a diverse array of projects, seemingly linked by the need to clone, manipulate DNA in weird and wonderful ways and engineer protein.

Ever tried sticking a 5 nm gold nanoparticle onto a protein using an engineered cysteine? I have. Don’t ask.

As a grad student I spent many years demonstrating, which is a job that you can either throw yourself in to, or alternatively turn up, grunt a few times at the undergrads and take your money; I was of the former persuasion, though I certainly had plenty of the latter in my time as an undergrad.

It was always great fun having control of a bench of undergrads for a full year as you dragged them kicking and screaming through procedures and experiments, the like of which many of them will ever have to do again (even as research scientists). However, what sticks in my memory most of all were those times when the little darlings didn’t quite click with what they were supposed to be doing; there were sometimes truly spectacular lapses in common sense.

One incident took place during a microbiology skills practical. The class were to be learning about oil-immersion microscopy. They were told how the refraction of light through a glass sample slide prevents the use of higher resolution magnifications, but one way round this is to use oil with the same refractive index as glass. By using an oil layer between the lens and the slide, the refraction is lost and we can achieve higher magnification.

“Sir….?” (yes, they were freshers, still in ‘school-mode’)

“Jim. Yes? What’s the problem?”

“It doesn’t work, the samples are all fuzzy”

“Have you focussed them correctly?”

“The microscope won’t focus at all, it’s broken.”

“….so tell me again what you did exactly.”

It turned out they had taken oil-immersion rather literally and, having removed the high magnification lens from the microscope and filled it to the top with oil, they’d screwed the lens back onto the microscope and now had some problems.

“….! Erm, the oil goes on the top of the cover slip, on the glass slide you’re looking at, NOT in the microscope itself.”

As I said, great memories. Next time I’ll tell you about the group of lads who eagerly, and with great attention, streaked E. coli out to single colonies – directly onto the bench top (even though there were a stack of agar plates for them to use). The mind beggars.

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