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calling all chemistry teachers...

... & other devotees of things that go 'bang!'

Years ago now, I stood in for the HoD Science at a Manawatu high school. He was a chemist, & loved doing demonstrations. So before he went on leave, he walked me through some of his party tricks so that I'd get them right. I still remember him asking me if my hands sweated when I got nervious. Why? I said. Well, he said, if they do you won't be able to do this... & proceeded to roll a little bit of sodium into a ball before putting it into a deflagrating spoon! (He then proceeded to ignite the stuff & lower it into a gas jar full of chlorine.) I thought, ulp! His piece de resistance was to fill several condoms with hydrogen, attach them by strings to the ends of the seat rows in the assembly hall, & then proceed down the aisle & light them one by one. The kids loved it.

He probably wouldn't do these 'tricks' these days, though. In some ways this is probably a good thing (the memory of the balls of sodium is still with me!), & there are good arguments for not using bangs & explosions just for their own sake in the classroom. Students will remember them, but there doesn't seem much point if they don't also gain an understanding of the underlying scientific principles. But at the same time, chemistry could get a bit staid without them :-)

Where is this going? Well, I've just come across (courtesy of Ben Goldacre again) the most wonderful set of chemistry & physics demonstrations, all on video. Equipment, methods, explanations, it's all there. As Ben says, it's a bit tedious having to sit through the same introductory clip on each of them, but it's only for 20 seconds or so. My current favourite isthe balding gentleman with a stack of foil cupcake cases on his head - he touches a van der Graaf generator (while standing on a rubber mat), it's then turned on, & the cake cases fly off his head in a steady stream! (Apparently you need a bald volunteer to help with this one. I imagine that in someone with a full head of hair, the cake cases & the hair could develop an entanglement problem.) Mind you, the whoosh! bottle isn't bad either :-)

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