Archive for Physics

Does the fine structure constant vary?

Posted in The Universe and Stuff with tags , , on November 16, 2016 by telescoper

No.

Thinking of Applying for a PhD Place in Physics or Astronomy?

Posted in Education with tags , , , , , , on October 12, 2016 by telescoper

This morning I am to give a short talk to interested students within the School of Physics & Astronomy here at Cardiff University about postgraduate research in which I aim to pass on some, hopefully useful,  information about how to go about applying for PhDs  in Physics  and Astronomy. Since I’ve finished writing the talk more than the usual few minutes before I have to deliver it, I thought I’d jot down here a few general remarks that might be useful to people elsewhere who are thinking of taking the plunge when they graduate. I’m aiming this primarily at UK students applying for places in the UK; special considerations apply for students wanting to do graduate research abroad.

What is a PhD? The answer to that is relatively easy; it’s a postgraduate research degree. In order to obtain a PhD you have to present a thesis like that shown on the left (which happens to be mine, vintage 1988), typically in the range 100-250  pages long. A thesis has to satisfy two conditions for the award of the degree: it should contain original research, which is publishable in an academic journal; and it should present a coherent discussion of that original work within the context of ongoing work in the area of study. In Physics & Astronomy, the PhD is pretty much a prerequisite for any career in academic research, and it usually takes between 3 and 4 years to complete. After submission of the thesis you will have to undergo a viva voce examination conducted by two examiners, one internal and one external. This is quite a tough test, which  can last anywhere between about 2 and about 6 hours, during which you can be asked  detailed questions about your research and wide-ranging questions about the general area.

The Money Side. In the UK most PhDs are supported financially by the research councils, either EPSRC (most physics) or STFC (nuclear & particle physics, astronomy). These generally award quotas of studentships to departments who distribute them to students they admit. A studentship will cover your fees and pay a stipend, currently £14296 pa. That doesn’t sound like a lot, but you should at least remember that it is a stipend rather than a wage; it is therefore not taxed and there is no national insurance payable. There is a fee (currently £4121) payable for a PhD course, but that only comes into play if you are planning to fund yourself. If you receive a studentship it will normally cover the fee as an additional component. What I mean by that is you don’t need to pay it out of the stipend, it is separate. In top of that, research council funding also supplies a Research Training Grant which covers, e.g., travel and small items of equipment so you don’t need to pay for those out of your stipend either.

How do I choose a PhD? During the course of a postgraduate degree you are expected to become an expert in the area in which you specialize. In particular you should reach the point where you know more about that specific topic than your supervisor does. You will therefore have to work quite a lot on your own, which means you need determination, stamina and enthusiasm. In my view the most important criterion in your choice of PhD is not the institution where you might study but the project. You need to be genuinely excited by the topic in order to drive yourself to keep through the frustrations (of which there will be many). So, find an area that interests you and find the departments that do active research in that area by looking on the web. Check out the recent publications by staff in each department, to ensure that they are active and to have something to talk about at interview!

Qualifications. Most universities have a formal requirement that candidates for admission to the PhD should have a “good honours degree”, which basically means at least an Upper Second Class Honours degree. Some areas are more competitive than others, however, and in many disciplines you will find you are competing with a great many applicants with First Class degrees.

How to apply successfully. The application procedure at most universities is quite simple and can be done online. You will need to say something about the area in which you wish to do research (e.g. experiment/theory, and particular field, e.g. cosmology or star formation). You’ll also need a CV and a couple of references. Given the competition, it’s essential that you prepare. Give your curriculum vitae some attention, and get other people (e.g. your personal tutor) to help you improve it. It’s worth emphasizing particular skills (e.g. computing). If you get the chance, make use of your summer vacations by taking on an internship or other opportunity to get a taste of research; things like that will undoubtedly give your CV an edge.

The Interview. Good applicants will be invited for an interview, which is primarily to assess whether you have the necessary skills and determination, but also to match applicants to projects and supervisors. Prepare for your interview! You will almost certainly be asked to talk about your final-year project, so it will come across very badly if you’re not ready when they ask you. Most importantly, mug up about your chosen field. You will look really silly if you haven’t the vaguest idea of what’s going on in the area you claimed to be interested in when you wrote your  application!

Don’t be shy! There’s nothing at all wrong with being pro-active about this process. Contact academic staff at other universities by email and ask them about research, PhD opportunities. That will make a good impression. Also, don’t be afraid to ask for advice. Although we’re all keen to recruit good PhD students for our own departments, we academics are  conscious that it is also our job to give impartial advice. Ask your tutor’s opinion.

How many places should I apply for? Some research areas are more fashionable than others so the level of competition varies with field. As a general rule I would advise applying for about half-a-dozen places, chosen because they offer research in the right area. Apply to fewer than that and you might lose out to the competition. Apply to many more and you might not have time to attend the interviews.

What’s the timetable?  Most applications come in early in the new year for entry to the PhD in the following September/October. The Christmas break is therefore a pretty good time to get your applications sorted out. Interviews are normally held in February or March, and decisions made by late March. STFC runs a deadline system whereby departments can not force students to accept or decline offers before the end of March, so there should be ample time to visit all your prospective departments before having to make any decisions.

That’s all I can think of for now. I hope at least some of these comments are useful to undergraduates anywhere in the UK thinking of applying for a PhD. If there are any further questions, please feel free to ask through the comments box. Likewise if I’ve missed anything important, please feel free to suggest additions in the same manner…

Worrying Times for UK Physics

Posted in Education, The Universe and Stuff with tags , on August 19, 2016 by telescoper

As I’m more-or-less in between jobs at the moment, this is the first August in many that I haven’t been involved the clearing and confirmation process that helps students find places at university after the A-level results are released. I know how stressful it is for admissions staff and prospective students alike, so I’m not sorry to be out of it for once!

On the other hand I did notice something worrying that seems to be the continuation of a trend I noticed last year.  I quote from a piece issued by the Institute of Physics about the number of students taking A-level physics last year:

Although there was an overall rise of 2% in the number of A-level entries, the number taking physics fell to 36,287 compared with 36,701 last year – the first time numbers have fallen since 2006. The number of girls taking physics rose by 0.5%, however.

That decline is slight, of course, and it was  obviously too early to decide whether it indicated whether or not the UK has reached “Peak Physics”. Well, this year has confirmed that trend. According to a piece by the Wellcome Trust the number of entrants for physics A-level has fallen further this year, from 36,287 in 2015 to 35,344 in 2016. The Institute of Physics has also commented.

Virtually all students who get a Physics A-level do go to university, but by no means all do physics. It is also a qualifying subject for engineering and technology programmes, as well as medicine. It’s not clear yet whether the decline in A-level entry reflects a decline in the number of students going to start physics degrees at University this year, but this seems probable. This is good news if you’re an applicant with a Physics A-level, of course, because it increases the chances of you getting a place, but it’s no so good for physics as academic discipline.

Physics departments in UK universities are already competing for a very small pool of students with a Physics A-level.  The removal of student number controls allows  large universities to recruit as many students as they like, so the competition between universities for such a small number of applicants is extremely intense. Moreover, some universities, e.g. Newcastle and Hull, have opened up physics courses that they had previously closed, and others have started  new programmes based on what was anticipated to be an overall increase in demand. To support this expansion, many institutions have recruited extra numbers of teaching faculty assuming the salary costs would be covered from tuition fees. If the decline in overall student numbers continues then the budgets of many physics departments are going to look pretty grim, with potentially serious  consequences for the long-term sustainability of physics in many institutions.

I have to confess I’m worried. The physics community urgently needs to find out what is behind this fall. It’s not restricted to physics, in fact. Both biology and chemistry have also experienced a decline in the number of A-level entrants (from 44,864 to 43,242 and from 52,644 to 51,811 respectively), but the effect on physics is likely to be greater for the reasons I discussed above.

Mathematics numbers have also fallen, but by a much smaller percentage and from a much higher level: from 92,711 to 92,163.  I‘ve argued before that there’s a case on a number of grounds for scrapping the physics A-level as a requirement for entry to university as long as the student has mathematics. That may be a step too far for some, but it’s clear that if physics is to prosper we all have to think more creatively about how to increase participation. But how? Answers on a postcard – or through the comments box – please!

 

 

Private Eye on Physics Graduation

Posted in Education, The Universe and Stuff with tags , , on July 19, 2016 by telescoper

Given the occasion I thought I’d just post this rather excellent cartoon I saw last year  Private Eye

Physics Graduation

To Cambridge Again

Posted in Biographical, Education with tags , , , on June 13, 2016 by telescoper

The annual cycle of academic life brings me once again to my duties as External Examiner for Physics at the famous Midlands University called Cambridge, so I’m getting ready to take the train there. Here’s a picture of the Cavendish laboratory where I’ll be working for the next three days:

bragg_building_110309

It hasn’t changed much since I was an undergraduate there (I graduated 31 years ago), but the area around it has certainly been heavily developed in the intervening years.

Anyway, I’d better be going. Toodle-pip!

R.I.P. Tom Kibble (1932-2016)

Posted in The Universe and Stuff with tags , , , , , on June 2, 2016 by telescoper

Yet again, I find myself having to use this blog pass on some very sad news. Distinguished theoretical physicist Tom Kibble (below) passed away today, at the age of 83.

Kibble

Sir Thomas Walter Bannerman Kibble FRS (to give his full name) worked on  quantum field theory, especially the interface between high-energy particle physics and cosmology. He has worked on mechanisms ofsymmetry breaking, phase transitions and the topological defects (monopoles, cosmic strings or domain walls) that can be formed in some theories of the early Universe;  he is  probably most famous for introducing the idea of cosmic strings to modern cosmology in a paper with Mark Hindmarsh. Although there isn’t yet any observational support for this idea, it has generated a great deal of very interesting research.

Tom was indeed an extremely distinguished scientist, but what most people will remember best is that he was an absolutely lovely human being. Gently spoken and impeccably courteous, he was always receptive to new ideas and gave enormous support to younger researchers. He will be very sadly missed by friends and colleagues across the physics world.

Rest in peace, Tom Kibble (1932-2016).

 

Examination Time Yet Again

Posted in Biographical, Education with tags , , , , , on May 12, 2016 by telescoper

Once again the return of glorious weather heralds the return of the  examination season at the University of Sussex, so here’s a lazy rehash of my previous offerings on the subject that I’ve posted around this time each year since I started blogging.

My feelings about examinations agree pretty much with those of  William Wordsworth, who studied at the same University as me, as expressed in this quotation from The Prelude:

Of College labours, of the Lecturer’s room
All studded round, as thick as chairs could stand,
With loyal students, faithful to their books,
Half-and-half idlers, hardy recusants,
And honest dunces–of important days,
Examinations, when the man was weighed
As in a balance! of excessive hopes,
Tremblings withal and commendable fears,
Small jealousies, and triumphs good or bad–
Let others that know more speak as they know.
Such glory was but little sought by me,
And little won.

It seems to me a great a pity that our system of education – both at School and University – places such a great emphasis on examination and assessment to the detriment of real learning. On previous occasions, before I moved to the University of Sussex, I’ve bemoaned the role that modularisation has played in this process, especially in my own discipline of physics.

Don’t get me wrong. I’m not opposed to modularisation in principle. I just think the way modules are used in many British universities fails to develop any understanding of the interconnection between different aspects of the subject. That’s an educational disaster because what is most exciting and compelling about physics is its essential unity. Splitting it into little boxes, taught on their own with no relationship to the other boxes, provides us with no scope to nurture the kind of lateral thinking that is key to the way physicists attempt to solve problems. The small size of many module makes the syllabus very “bitty” and fragmented. No sooner have you started to explore something at a proper level than the module is over. More advanced modules, following perhaps the following year, have to recap a large fraction of the earlier modules so there isn’t time to go as deep as one would like even over the whole curriculum.

In most UK universities (including Sussex), tudents take 120 “credits” in a year, split into two semesters. In many institutions, these are split into 10-credit modules with an examination at the end of each semester; there are two semesters per year. Laboratories, projects, and other continuously-assessed work do not involve a written examination, so the system means that a typical  student will have 5 written examination papers in January and another 5 in May. Each paper is usually of two hours’ duration.

Such an arrangement means a heavy ratio of assessment to education, one that has risen sharply over the last decades,  with the undeniable result that academic standards in physics have fallen across the sector. The system encourages students to think of modules as little bit-sized bits of education to be consumed and then forgotten. Instead of learning to rely on their brains to solve problems, students tend to approach learning by memorising chunks of their notes and regurgitating them in the exam. I find it very sad when students ask me what derivations they should memorize to prepare for examinations. A brain is so much more than a memory device. What we should be doing is giving students the confidence to think for themselves and use their intellect to its full potential rather than encouraging rote learning.

You can contrast this diet of examinations with the regime when I was an undergraduate. My entire degree result was based on six three-hour written examinations taken at the end of my final year, rather than something like 30 examinations taken over 3 years. Moreover, my finals were all in a three-day period. Morning and afternoon exams for three consecutive days is an ordeal I wouldn’t wish on anyone so I’m not saying the old days were better, but I do think we’ve gone far too far to the opposite extreme. The one good thing about the system I went through was that there was no possibility of passing examinations on memory alone. Since they were so close together there was no way of mugging up anything in between them. I only got through  by figuring things out in the exam room.

I think the system we have here at the University of Sussex is much better than I’ve experienced elsewhere. For a start the basic module size is 15 credits. This means that students are usually only doing four things in parallel, and they consequently have fewer examinations, especially since they also take laboratory classes and other modules which don’t have a set examination at the end. There’s also a sizeable continuously assessed component (30%) for most modules so it doesn’t all rest on one paper. Although in my view there’s still too much emphasis on assessment and too little on the joy of finding things out, it’s much less pronounced than elsewhere. Maybe that’s one of the reasons why the Department of Physics & Astronomy does so consistently well in the National Student Survey?

We also have modules called Skills in Physics which focus on developing the problem-solving skills I mentioned above; these are taught through a mixture of lectures and small-group tutorials. I don’t know what the students think of these sessions, but I always enjoy them because the problems set for each session are generally a bit wacky, some of them being very testing. In fact I’d say that I’m very impressed at the technical level of the modules in the Department of Physics & Astronomy generally. I’ve been teaching Green’s Functions, Conformal Transformations and the Calculus of Variations to second-year students this semester. Those topics weren’t on the syllabus at all in my previous institution!

Anyway, my Theoretical Physics paper is next week (on 19th May) so I’ll find out if the students managed to learn anything despite having such a lousy lecturer. Which reminds me, I must remember to post some worked examples online to help them with their revision.