Those were the days Part 25

Old School Science

There used to be a position in the teaching profession that had a very basic job title – “senior teacher”. As opposed to the modern terms such as “assistant vice principal” or “associate head teacher”, the position of senior teacher was a post that was simple and easy to get to grips with. The position could be quantified by the fact that it merited an “E allowance” on the old pay scale.
You were experienced, respected, and on the ball if you were a senior teacher. They knew what they were doing. Some were gun slingers (do we call them behaviour managers now?), some were planners and organisers (suppose these folks are now SIMS/curriculum/timetable coordinators today), but one thing that they had in common was they were all superb classroom practitioners and had a bit of presence about them (were they old school ASTs?) All I know is I do not see them around these days – dinosaurs I suppose, killed off by the “fast trackers” and well-dressed office types.
Jim Chinnor was a senior teacher who remained in the same school long enough to teach the kids of the kids he had taught a generation before.  Physics was his specialism. He was a legend.

Jim was a pure magician when it came to holding a class’ attention.  The way he held most groups’ interest was through his anecdotes and stories that related to the science theories that he was teaching and he also loved a good practical – as most kids do.

He had a special way of demonstrating to students the principle of heat conduction in a metal bar. The bog standard way is to stick drawing pins onto a copper bar using wax or petroleum jelly. (See video below) When the bar is heated with a Bunsen at one end, the conducted heat travels down the bar and melts wax so the pins drop one by one as the heat is conducted along the bar.

Now Jim Chinnor loved the spectacular, so he adapted the method above by using white phosphorus rather than relying on waxed pins. White phosphorus burns almost spontaneously in air; it has to be stored away in a sealed container in a locker or chemical bin outside of any building.  Phosphorus was used by the RAF in the incendiary bombs dropped on German cities towards the end of World War II. It is nasty stuff and has to be treated with respect.

The brainwave that Jim had was to put small pieces of white phosphorus on the copper bar which would catch alight in turn as the warmth from the bar became enough to start the reaction of phosphorus with air. Jim made two mistakes when doing this demonstration for his students, firstly he did not set out the equipment in a fume cupboard and secondly he forgot about the stock bottle of white phosphorus and left the lid off it.

Jim was chirping away to his group when suddenly he realised that the stock bottle of phosphorus had been left open too long and the air had got to the volatile chemical. The whole bottle caught fire belching out loads of noxious fumes and because the bottle had not been put in the fume cupboard the room quickly filled with smoke. By now the bottle was too hot to pick up and put in the fume cupboard or taken outside, so a rapid evacuation took place. All the kids got out without any mishaps, but the bottle continued to burn and fumes spread up through the ceiling into the room above the lab, leading to mass panic in a German class. The fire was eventually put out, but not early enough to stop the chemical mess from spreading around the lab and the room above. The building got condemned by a HSE inspector and it was a week before the whole place got cleaned up!

Today you would not see such a practical attempted, but an “interactive” visual aid would be shown to the class instead, ie another POWERPOINT©

But watching the video below you can see why Jim tried to jazz up the demonstration a bit!

One comment

  1. Pingback: Those were the days Part 26 | Next goal wins laaaaaaads!

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