Saturday, 13 March 2010

Today we went to the Cambridge Science Festival. Last year we spent an entire day looking at biology stuff, largely on the back of C's interest in such things when we were in the US. This time I was keen to try chemistry. Suggestions that he might like it have been ignored up to now, so the idea was to dangle it in front of him and see whether he liked it.

We got kitted out with white lab coats and safety goggles for the first bit, and had a play with coloured slime. The slime was quite simple - PVA glue, a bit of food colouring, mix well in a ziplock bag and then add some 4% borax solution. It sets to a workable slime.

Next was the crazy chemistry section, where we started with a simple volcano using sodium bicarbonate and and vinegar. There was a slightly different type of volcano on an adjacent bench, made with water, washing-up liquid, mix well in a conical flask and throw in some dry ice. C discovered that he could make a column of soap bubbles almost as high as he could reach before the weight of the water overcame the surface tension and it collapsed. Other experiments of interest were the salt and vinegar cleaning copper coins, zinc-plating twopence pieces and some fun stuff with catalysts. C also got to melt a polystyrene cup in acetone.

We gave back the lab coats and glasses and headed for safer areas. A bit of crystal growth, plus looking at some impressively-large crystals and some really small ones under a microscope. Then another fun bit - a bunch of students with vats of liquid nitrogen, so C got to smash a daffodil and observe bananas, apples and carrots meet the same fate. Other fun was had by immersing balloons into liquid nitrogen, whereupon they would be almost deflated when removed and would re-inflate to full size as they warmed up. I assume that the gas in the balloons had condensed to liquid to make them shrink that much.

C put together a model of a menthol molecule, then we had a break for a drink and some biscuits, followed by more liquid nitrogen fun, making ice cream.

Then it was pretty much closing time - where did the time go?

The final comment is that yes, he appears hooked on chemistry, so we stopped off in a bookshop and have acquired a suitable book to start working from. Now if only we could get a proper chemistry set, as seen back in the 70s with real chemicals in it.

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