07Dec11 Diamagnetism DemoOn Wednesday, some of our physics class went to a lecture about superconductivity, where I accidentally put my finger in liquid nitrogen. The demonstration was a magnet levitating above a dish of yttrium barium copper oxide superconductors (which required cooling to -150C in order to actually work, hence the need for liquid nitrogen). Superconductors are materials with zero electrical resistance, so once a current is flowing in one, it can keep going for billions of years. A magnet placed near a superconductor will induce a current in the superconductor with an associated magnetic field that directly opposes it, and hence the magnet levitates. But as the superconductor had warmed up, the magnet fell down and became attached to it. So when I tried to lift the magnet, the superconductors and dish of liquid nitrogen came with it, and the rest is history.

But putting my finger in liquid nitrogen was actually not as bad as standing beside the Abercorn Basin later that day in a December gale, looking for a female Long-tailed Duck!

07Dec11 Lagan Ferry Docks

When I arrived at the Lagan, walking under the M3, I though I’d found it – a black-and-white bird swimming and diving in the river beside the Odyssey Arena. On closer inspection it was actually a kind of auk which I’d never seen before.

07Dec11 Guillemot

There were two of them, both with a distinctive black eye line through their white faces. I headed on round the path, past a young cormorant fishing in the Abercorn Basin, past the Titanic Museum, down the road to the Titanic dock before I realised I had overestimated the amount of time I had, and had to turn back.

07Dec11 Titanic Museum Belfast

Returning to the Odyssey, I found three of the auks now present – plus a mottled-white Tystie… and then I had my doubts. Were the unidentified auks simply Tysties in winter plumage?

Looking at my RSPB Birds of Britain and Europe, it turns out all Tysties / Black Guillemots have mottled-white plumage in winter, and the black-and-white auk I saw was actually a Guillemot – my 110th British bird!

But wait! That’s not all I saw at the Lagan…

07Dec11 Starling Murmuration

To be continued…

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