Blowing Smoke

I’ve been trying to make myself useful over the last few days thinking about the new module I’m supposed to start teaching in October. I’m a bit daunted by it to be honest. The title is The Physics of Fields and Flows and it will be taken by students when they return to start their second year after the summer break.  It’s twice the size of our usual modules, which means a lot of teaching and it’s all new for me, which means a lot of preparation.

The idea behind introducing this module was to teach a number of things together which previously had been taught in separate modules, specifically electromagnetism and vector calculus, or not at all, e.g. fluid mechanics. I’m not sure when or why classical fluid mechanics dropped out the syllabus, but I think it’s an essential part of a physics curriculum in its own right and also helps develop a physical understanding of the mathematics used to describe electric and magnetic fields. It’s one of the unhappy side-effects of modular teaching that it hides the important underlying connections between apparently disparate phenomena which are the essence of what physics is about.

Another thing I reckon we don’t do enough of these days is use lecture demonstrations. That’s harder to do these days because we tend to use pooled lecture theatres that don’t have the specialist equipment that they might have if they were dedicated to physics lectures only.  Practical demonstrations are now usually given second-hand, by using video clips.  That’s fine, but not as good as the real thing.

Anyway, it struck me that it would be quite easy to arrange a demonstration of the transition between laminar and turbulent flow using the simple and relatively inexpensive equipment shown in the rather beautiful image. Unfortunately, however, demonstrating this sort of thing isn’t allowed on University premises even for scientific purposes…


5 Responses to “Blowing Smoke”

  1. Alex Rogers Says:

    Such a demonstration would have extra appeal to astronomers as the particles in cigarette smoke are of the same size as dust in the interstellar medium.

    • telescoper Says:

      I bet the ISM doesn’t pay as much tax…

    • Bryn Jones Says:

      I can remember Mayo Greenberg giving a cigarette smoke demonstration at a conference in Cardiff around 1994 about dust in galaxies. He lit a cigarette and held it above an overhead projector to show that small quantities of tobacco smoke can absorb light effectively, drawing parallels with interstellar dust.

      Mike Disney then pointed out that there was a smoke detector immediately above the projector. He warned it might set off fire alarms, and might even trigger water sprinklers. That brought a sudden end to the demonstration.

  2. Invite Cyril Isenberg to give his (brilliant) talk on the science of soap bubbles. I dare say he’ll light a cigarette during it, regardless of rules.

  3. Anton Garrett Says:

    What a drag!

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