If there is one statement that could go undisputed about being a lecture, its that the job is varied! Thursday (28th April) was one day that embodied that statement. It was a good day, all in all, but a very tiring and long one.
After getting to work around 8.20 am I immediately set out to forage for the last few chemicals and bits of equipment needed for events later in the day. After running round for about an hour like a headless chicken, I was in proud possession of a bottle of bromine, several wooden splints, a hot plate, two bunsen burners and variety of heatproof mats. Fortunately, my co-conspirator, R was also running around finding the odd things still needed for our demo lecture later in the day (i.e. filling balloons with hydrogen, helium, argon, nitrogen; collecting liquid nitrogen and dry ice). By 10 am I fell into a meeting (and had welcome cup of tea) to discuss recent exam and course work marks for a bunch of students. That went on a little longer than expected as we fell in to a discussion on the future of that particular course and the relative uncertainty of funding for a related course for the next year. Basically the incompatibility of Government and University timeframes will make organisation a little tricky.
As I wandered back to my office I remembered that I’d received an email from one of our finalists asking if they could ask some questions before their exam next week. I’d forgotten to reply first thing, but fortunately they were in the computer classroom near my office so I was able to drop in and answer the questions. As the clock struck noon, I charged to the lab to get set up for a session on ‘exciting chemistry demonstrations’ with a group of teachers who were accompanying some gifted and talented school children at the Salters’ Festival of Chemistry, an annual event at my university and a few others. R set up the zinc plating of copper coins experiment, while I set up for cannon fire, and the reactions of the halogens (just iodine and bromine) with aluminium in various forms. I’ll post a some videos of them at some point. I had to stop to laugh when I found R and one of the education staff sitting in the lab having a right old gossip while shredding aluminium foil for the experiment!
At 12.45 pm we were (just about) ready for the teachers. R did the old copper – ‘silver'(zinc plating) – ‘gold’ (annealed to brass” trick. Fortunately the coins that I’d hastily cleaned with hydrochloric acid worked really well. I did the reaction of aluminium powder and iodine which involves approximately a 10:1 ratio of finely ground iodine: powdered iodine, mixed on heat proof mat. One drop of water sets the reaction off and it produces a rather beautiful cloud of purple smoke (photos and perhaps video to follow, once I find some willing volunteers to do it). I’d never done the reaction before so was quite pleased with it. The second reaction, bromine (a liquid) with common household aluminium foil produced some nice white smoke and a few hisses and sparkles. Both were acceptable reactions but took a while. Cannon fire, on the other hand, that goes with a bit of a bang as you’d imagine from the title. Basically you get a basin of ethanol and hydrogen peroxide, set it alight then tip in a spatula tip of potassium permanganate (that’s the purple crystal stuff). The permanganate causes the peroxide to decompose producing bubbles of oxygen that explode on ignition in the ethanol, producing a series of sharp bangs and crackles, and a pretty pale lilac flame. The session seemed well received by the teachers and we handed out full instructions that I’d finished off and photocopied at some point earlier in the day.
Unfortunately I had to run at that point, to set up for a lecture demonstration with the children attending the Salters’ festival of chemistry! More on that in part II!