Thursday, 25 March 2010

Voted off

Well, I got voted off of I'm A Scientist. Never mind! It was good fun trying to answer all the questions, and chatting to school kids about science. And hats.

This post serves to provide something for anyone who still didn't get a chance to ask me questions in the competition to ask me, now that I'm out. Please feel free to comment with questions!

Wednesday, 24 March 2010

Survived the first eviction

Well, I survived the first eviction. Woo! I feel a bit bad for Sarah, though. What she does is really interesting, but I think computer science is a harder sell than disease-curing biosciences, or gee-whizzy space stuff. I hope she prompted some of the kids to think about things like computer science as proper science. She pointed them to Project Euler, too, and maybe some of the more keen ones will get started with the problems there. Which reminds me, I should try some more of them too. My solved problems page is looking a little weak.

Saturday, 20 March 2010

Get me out of here?

We're half way through I'm a Scientist Get Me Out of Here. From Monday, the students will start voting us off. Eek! Hopefully I won't be gone on the first day. They've just fixed the website so that you can see all the questions that we've been asked and what answers we've given. Mine are here. It's sort of a shame, but completely reasonable, that people not in the competition can't comment. Feel free to comment here though :-)

Monday, 15 March 2010

I'm A Scientist Get Me Out Of Here

The two-week run of I'm A Scientist Get Me Out Of Here started today, and I've had quite a few questions from the kids taking part so far. Have a look at the lithium zone on their site to see what questions I, and the other scientists, have been asked. It's been pretty interesting to find out what sort of things the student are interested in. Everything from "was it really hard work to get where you are now?" to "do you harm animals in your work?" (quick answers: kinda and no)

Tuesday, 2 March 2010

The new alchemists

One of the cool things doing nuclear physics is that it has realised the old alchemists' dream of turning lead into gold - or indeed any element into any other. While one of my colleagues has genuinely turned lead into gold, some of the most exciting work in nuclear physics comes from trying to make new elements.

The chemical elements start with element 1 - Hydrogen - with one proton in the nucleus, then on to element 2 - Helium - with two protons and so on. The heaviest element that you can dig out of the earth (in trace amounts) is Plutonium, with 94 protons. Beyond lead (element 82) all known nuclei are unstable against decay into lighter nuclei with characteristic lifetimes ranging from tiny fractions of a second to many trillions of years. As one gets, though, to heavier and heavier elements, the lifetimes get shorter and any nuclei heavier then plutonium that might have existed on the Earth have long decayed. This doesn't stop us trying to make new elements in the laboratory, though, to better understand the forces between neutrons and protons, and to try to understand what isotopes may have been made in nuclear reactions in stars.

These "superheavy" elements are made by colliding two lighter nuclei together and hoping that they fuse together. One then looks for the alpha particles that come from the decay and the resulting residual nucleus which one can hopefully identify as a known nucleus. Indirectly, by studying the decay chain, one gets a "genetic fingerprint" for the original superheavy nucleus. Recently, however, a group based at the GSI facility in Germany has actually measured a superheavy nucleus' mass directly, rather than by inferring it from the decay. By trapping it in a magnetic field and observing how fast it oscillates round the trap, one can determine its mass very accurately. Knowing the mass is important, as it is a measure of the stability of the nucleus. This helps us point to the possibility that there is a more stable region of superheavy nuclei inaccessible to experiment as yet, but containing nuclei long lived enough to make an appreciable amount of material from.

The work is published in Nature, and the IoP's Physics World blog has already reported it. It's perhaps not as earth-shattering, but before the Nature paper appeared, a PhD student of mine, and myself submitted a theoretical paper on the likely appearance of especially superheavy nuclei with very large numbers of neutrons. Fingers crossed the referees will return with positive comments!