Tuesday, 23 July 2013

How many physicists does it take to change a lightbulb?

A little while ago, the BBC solicited scientists to tell jokes on the TV as part of series.  Each episode was supposed to consist of a particular group of people, connected only in some non-comedic way, telling jokes.  It started with old jews and seems to have passed through vicars, and has now reached scientists.  Only, with scientists, the BBC went for the pejorative boffins instead.

The boffins show is on tomorrow night, at 10pm on BBC4.  Unless they've cut me out, I'll be in there.  The preview, below, starts with my colleague Paddy Regan:

Saturday, 20 July 2013

Physics & Astronomy at Surrey

I spent much of Thursday this week in a meeting to defend the proposal of the Physics Department at my University to start a degree course in Physics with Astronomy to the University accreditation committee. The word "defend" sounds a bit, well, defensive.  Really, it was not like that, but more that there are a lot of checks to me made, regarding things like syllabus coverage, reasonable methods of teaching and examining, and conforming to University and national expectations, that a panel is always convened to check that we are acting in a sensible way in proposing our new degree.  This is rather a British way of doing things, and depending on where you are in the world, you may find the "professionalisation" of degree specifications surprising or not.

Our Physics and Astronomy programme is new, because we have just appointed a new, and pretty large, astro group.  The external examiners included members from the University of Sussex, who have a more established astro programme.  Historically, we have often been confused for Sussex, perhaps since our names both match the S - U - double consonant - E - consonant at the end of the alphabet pattern.   Hopefully our move into astronomy won't make matters worse.

Anyway, the panel were impressed with our degree, and we'll therefore be teaching it from this October onwards.  It'll be pretty exciting, I think, having a larger and more general group of both staff and students, and I look forward to seeing our new telescope on top of the management school building.  I wonder what the inhabitants of that building will make of it.

The picture attached to this post is from the research website of our new group.  Take a look here to find out more.

Saturday, 13 July 2013

Do I use two-by-two matrices when I write papers?

I received an email today, with a subject, "Do you use two-by-two matrices when you write papers?"

It seems like a rather strange question, and it comes as part of an email soliciting papers for a new open access journal that I haven't heard of.  They are running a special issue on "Physics based on two-by-two matrices".  Now, these objects crop up all over the place; in rotations, for example.  In any two-level mixing problem.  Or they can be used to describe quantum mechanical particles with an intrinsic "spin" angular momentum, such as protons, neutrons and electrons, so yes - very applicable to my work in nuclear physics.  

The question sounds so generic.  "Do you use numbers?" might be as apt, yet it is also so specific - particularly concerning itself with matrices of a particular size.  I can't help but think that it is a rather contrived way to promote interest in a new journal that charges a minimum of 500CHF (about £350) to authors to publish each paper.  Perhaps I am being unduly sceptical and when the special issue comes out, I will discover that there are a slew of article showing profound links between diverse areas of physics.  That is, if I even notice the issue be released amongst the huge number of very general new journals out there.

Tuesday, 9 July 2013

Marking Errors

In a recent post, I mentioned the need to deal better with errors and statistical analysis amongst theoreticians and modellers in nuclear physics than we habitually do at present.  Apart from the fact that I'm co-oraganising a workshop on the topic, my post was spurred by a conversation I had at a workshop in Poland.  One of the comments in the recent post, about assumptions in methodology, made me think of something that I usually think about at this time of year, namely: How accurately can we measure student achievement?

We (and I mean teachers and academics in general, rather than my department at my University) set a lot of different kind of assignments for students and generally give them a numerical score for each assignment.  To make the case simple to discuss, let's restrict it to my field of Physics, where most assignments have pre-determined mark schemes, that can be very detailed and prescriptive, written at the time of setting the assignment.  I have little doubt that we can mark (quite) faithfully according to the mark scheme, and therefore give a "precise" mark (in the usual language distinguishing precision from accuracy).  On the other hand, I'm not so sure that marks are so accurate.

For example, let's say one student takes one final year module, examined by me, and another takes a different optional module examined by my fictional colleague Dr Cruel.  We have both followed the guidelines to the best of our ability in terms of matching up our assessment to learning outcomes and level descriptors, and all the other sorts of things that the educationalists have made us think about, yet the mark a student gets in my course is much higher than in Dr Cruel's course.  The student put in the same amount of work in both courses.  Is it just that they revised the wrong thing in my course?  That they found the material differently difficult?  That I am a kinder marker?  

There are probably many reasons, and to some extent, they are all just part of the system, and students (and everyone else) must accept this.  And accept that there are factors like the luck of the style of the 2013 exam being one that a certain student was hoping for and another not, or vice versa.  Still, I certainly find it hard to argue that a student having a mark of 59.2% means that a lower second degree is absolutely the obvious outcome, whereas one with 60.1% absolutely has an upper second.  Actually - I guess I don't find that hard - they are rules which are set down, but I get really frustrated by people who are adamant that we mark to an accuracy of anything below a few percent.

Wednesday, 3 July 2013

The Unstable Nucleus

A new nuclear physics blog has hit the streets:  Ex-Surrey (and Cardiff) student and now York post-doc Dr Gemma Wilson's The Unstable Nucleus is live and definitely worth a read.  She has already beaten me by choosing a much less unwieldy name than "blog of the isotopes" with which I have encumbered myself.  I have added Gemma's blog to my reading list, and I heartily recommend it to others!

Also, while I'm at it, if you're not reading Miss Atomic Bomb, then you are missing the other great academic nuclear physics blog that's out there, and while I'm at it, I shall put in a word for Nuclear Secrecy which is a good read, more on the history and sociology of the nuclear age.

Information and Statistics in Nuclear Theory

This post is partly an advert for a workshop I'm co-organising in Glasgow on 19-20 August.  It's called "ISNET: Information and Statistics in Nuclear Experiment and Theory".  It's all about the linked processes in (nuclear) physics of performing experiments to measure some property of a system, and developing theoretical models of the same system, and in particular how to properly quantify things like the errors and uncertainties associated with the models.  These uncertainties have not always been treated with the same rigour in theoretical work as they are in experimental, but that is increasingly changing.  If you're a nuclear physicist and fancy coming along, please visit the workshop website and register.  There is no fee for the workshop, but also no support, so your institution will need to cover local expenses.

The other part of the post is to report on some broader issues related to the workshop.  I'm in Cracow, in Poland, at another workshop (this one on things we can do if a new nuclear research facility is built).  At the end of my talk, I advertised our workshop in Glasgow, and had a very interesting conversation with Thomas Duguet from Saclay afterwards.  Amongst many other interesting things, we discussed the problem of publications only giving the story of successful investigations.  Often (or perhaps always), both in experiment and theory, the process of arriving at the point at which you have some positive result to report, has involved a lot of getting things wrong, dead ends, trying fruitless methods, before finally getting a result.  Sometimes the result is only negative, in that only the absence of a hoped-for result is "discovered".  It is certainly not the case that these things never make it into print - there are plenty of results setting bounds on the existence of physical states through experiments that have been performed and not seen anything, but there is surely a lot of work out there that is never reported.  

There are all sorts of potential effects of this.  What will a historian of science conclude when they plumb the literature many years from now?  These parts of the scientific process will be hidden.  What happens to the career of a young scientist who does sterling work that only leads to ruling out the existence of something.  How will they be compared on the job market to someone who discovers something?  Then there is the waste of repeated labour - trying to do something that someone else has already explored exhaustively, but not reported that it didn't work.  Partly because of these issues, Thomas has been discussing with journal editors about starting a new series of articles which document the process of doing science, pitfalls and all.  

Monday, 1 July 2013

Sofia to Krakow

I feel rather tired.  Yesterday I was in Sofia and today I am in Krakow.  I spent the morning yesterday working in my hotel room until it was time to check out around 11.  Then my friend and colleague, Nikolay, picked me up to go to the Bulgarian National Museum.  His family came too, and we had a nice time eating together before going to the museum.  They were really friendly and the children were keen to speak English with me, which was nice.  I say children - one is about to go to university and the other not far behind, so "children" is perhaps not the right word.  Well, obviously, they are the children of my friend but ... well.  The museum was in a pretty grand building built by the communist authorities to impress visitors.  Lots of marble and grand rooms with ornate ceilings.  

The contents of the museum are all Bulgarian-related, starting from the earliest signs of human habitation in the form of stone tools and burial mounds (In the English translations, they used the word "tell" which I didn't recognise in that context, but is plausibly correct according to the Chambers Dictionary app on my phone).  Then there were artefacts from Thracian times through Roman, Byzantine, Old Bulgarian, Ottoman, and Bulgarian, stopping at the end of the second world war, just before the communist days.  I think the most impressive things were the Thracian gold items know as the Panagyurishte Treasure.  The fineness of the craft beat most things that came later in the museum.  The picture on the wikipedia page does not do them credit.  I'm afraid I didn't take a picture, though I can't claim that my phone would have done a better job than the wikipedia article photographer.

After the museum, I was dropped off at Sofia Airport.  I had to hang around for a while before Air Berlin were ready to check anyone in, but it all worked out okay, and I flew with them via Berlin Tegel to Krakow.  I arrived at around 11pm, made it to the hotel and fell asleep, only to wake up quite early as I was fretting (unnecessarily) about being fully prepared to talk at the conference here.  I finished tinkering with my talk, and headed to the planned excursion to the museum of the University.  It's an old university, with much history to celebrate, and their museum is pretty cool.  It's in a building of the university which is still sometimes used for formal events, and there are lots of artefacts, from things used to teach astronomy at the time Copernicus was there, through to donated items from famous Krakow residents, like Oscar and Nobel Prize medals.  We waited in the cloister for the famous clock to ring the hour, which then started a slightly silly mechanical display of characters moving around it.

Then to the conference.  It was pretty gruelling, in that it started after lunch, with two session of three hours each, with a coffee break in the middle.  Three hours per session is quite a lot to deal with, and what with being a bit tired from travelling I really struggled to fight the seminarcolepsy for the first hour or so before perking up.  I gave my talk in the second half.  It was okay - perhaps not as well-prepared as my talk in Bulgaria, but fine.  Really, I can't complain about my delivery, but I'd rather have done more calculations that I hadn't already talked about elsewhere.  Oh well.  I finished the evening by finding a nice vegetarian restaurant close to my hotel and coming back to listen to the Archers omnibus from yesterday and to write this.  

Since it's nice to include a picture in these posts, I include a picture of people taking a picture of the famous clock.