## In Praise of Natural Sciences

Posted in Biographical, Education with tags , , , , on April 24, 2016 by telescoper

The other day I was chatting with some students in the Department of Physics & Astronomy at the University of Sussex. One thing that came up was the fact that I’m basing the material for my Second Year Theoretical Physics module on the notes I took when I was a second-year undergraduate student at Cambridge over thirty years ago. I mentioned that to counter suggestions that are often made that the physics curriculum has been excessively “dumbed down” over the years. It may have been elsewhere, of course, but not on my watch. In fact, despite the misfortune of having me as a lecturer, many of the students in my class are picking up things far faster than I did when I was their age!

Anyway, that led to a general discussion of the changing nature of university education. One point was that in my day there weren’t any four-year “Integrated Masters” degrees, just plain three-year Bachelors. Teaching was therefore a bit more compressed than it is now, especially at Cambridge with its shorter teaching terms. We teach in two 12-week blocks here at Sussex. Week 11 of the Spring Term is about to start so we’re nearing the finishing line for this academic year and soon the examinations will be upon us.

The other thing that proved an interesting point of discussion was that the degree programme that I took was the Natural Sciences Tripos That meant that I did a very general first year comprising four different elements that could be chosen flexibly. I quickly settled on Physics, Chemistry and  Mathematics for Natural Sciences to reflect my A-level results but was struggling for the fourth. In the end I picked the one that seemed most like Physics, a course called Crystalline Materials. I didn’t like that at all, and wish I’d done some Biology instead – Biology of Cells and Biology of Organisms were both options – or even Geology, but I stuck with it for the first year.

Having to do such a wide range of subjects was very challenging. The timetable was densely packed and the pace was considerable. In the second year, however, I was able to focus on Mathematics and Physics and although it was still intense it was a bit more focussed. I ended up doing Theoretical Physics in my final year, including a theory project.

My best teacher at School, Dr Geoeff Swinden,  was a chemist (he had a doctorate in organic chemistry from Oxford University) and when I went to Cambridge I fully expected to specialise in Chemistry rather tha Physics. I loved the curly arrows and all that. But two things changed. One was that I found the Physics content of the first year far more interesting – and the lecturers and tutors far more inspiring – than Chemistry, and the other was that my considerable ineptitude at practical work made me doubt that I had a future in a chemistry laboratory. And so it came to pass that I switched allegiance to Physics, a decision I am very glad I made. It was only towards the end of my degree that I started to take Astrophysics seriously as a possible specialism, but that’s another story.

As we are now approaching examination season I’ve been dealing with some matters in my role as External Examiner for Natural Sciences (Physics) at Cambridge, a position I have held since last year. It’s certaintly extremely interesting to see things from the other side of the fence, thirty years on since my finals. In particular I was struck last year by how many senior physicists there are at Cambridge who actually came as undergraduates expecting, like I did, to do Chemistry but also then switched. No doubt some moved in the opposite direction too, but the point is that the system not only allowed this but positively encouraged it.

Looking back, I think  there were great educational advantages in delaying  the choice of speciality the way a Natural Sciences degree did. New students usually have very little idea how different the subject is at university compared to A-level, so it seems unfair to lock them into a programme from Year 1. Moreover – and this struck me particularly talking to current students last week – a Natural Sciences programme might well prove a way of addressing the gender imbalance in physics by allowing female students (who might have been put off Physics at school) to gravitate towards it. Only 20% of the students who take Physics A-level are female, and that’s roughly the same mix that we find in the undergraduate population. How many more might opt for Physics after taking a general first year?

Another advantage of this kind of degree is that it gives scientists a good grounding in  a range of subjects. In the long run this could encourage greater levels of interdisciplinary thinking. This is important, since some of the most exciting areas of physics research lie at the interfaces with, e.g. chemistry and biology. Unfortunately, adminstrative structures often create barriers that deter such cross-disciplinary activities.

Posted in Education with tags , , , on April 19, 2016 by telescoper

There’s been a predictably strong reaction from academic colleagues to an announcement by the University of Edinburgh that it is introducing a new staff monitoring policy that will require employees to tell management if they leave their “normal place of work” for half a day or longer.

Some have argued that this is measure is simply unenforceable and that the University concerned will have to employ extra people if all academics have to notify a management person every time they travel somewhere off campus. Perhaps the plan is to have all staff fitted with microchips like we do with pets so we can find out where they are if they go wandering off, or get temporarily adopted by friendly neighbours.

I did some time ago draft an April Fool email in which I claimed  my current employer was going to extend the attendance monitoring we perform with undergraduate students (which is partly to assess usage of teaching spaces and thus improve timetabling efficiency) to include academic staff, so we could assess usage of office space on a similar basis. I never sent the email because I thought too many would think it was real and get very angry. Although being at least slightly credible is an essential part of an April Fool, causing a riot is not.

Here at the University of Sussex academic staff are obliged to inform the University (via an official form) if they are travelling elsewhere in the course of their duties. In practice this form comes to the Head of School, which is me in in the case of Mathematical and Physical Sciences. This bit of bureaucracy is primarily for insurance purposes, but also means we have a record of where to contact people in case of emergency.

Most staff comply with this procedure  if they are travelling abroad, but they don’t always do so when they’re travelling in the UK for a day or so, e.g. for doing a PhD examination or something like that. Staff also often fail to let us know if they are working from home, which some (especially theorists and mathematicians) do a lot in order to get on with their research without interruption. Although this doesn’t often cause problems, I think it is reasonable that we should be able to get in touch with staff when they’re doing that (in case, e.g., one of their academic advisees has a problem) but it seems to me excessive that they should have to inform someone at an official level every time they work off campus for whatever reason. Leaving a contact phone number for use during working hours is quite adequate.

It seems to me that behind this move by the University of Edinburgh there’s the managerialist suspicion that everyone must be a shirker at heart. In fact one of the problems I have as a manager is not persuading staff to work longer hours, but to  stop working  excessively long hours.  I don’t think I’ve succeeded, largely because I haven’t found a way of doing my job at the same time as achieving  a sensible work-life balance.

Anyway, the point is that academic contracts do not usually specify where staff should work. There is a good reason for this, which is that the job is very diverse and replies flexible work arrangements. Academic contracts do not usually specify fixed hours of work per week, either, for the same reason. Some don’t even give a specific holiday entitlement. Staff in technical and professional service areas generally have contracts that specify both. I floated an idea at a staff that academics should file an official log of official leave. It wasn’t a popular suggestion because academic staff thought there was an implication that they were skiving by taking excessively long holidays. In fact my motivation was quite the opposite: to try to ensure that they take all the leave to which they are entitled.

## Opportunities in Mathematics, Statistics and Probability at Sussex University

Posted in Education with tags , , on April 16, 2016 by telescoper

It seems a good time for a quick post to point out that we have some jobs available in the Department of Mathematics at the University of Sussex. These posts have been made available following the University’s annual strategic planning process, in which it is one of my main responsibilities as Head of the School of Mathematical and Physical Sciences to put forward plans for future developments. The new positions are intended both to expand and diversify our research base in Mathematics and Statistics, but also to provide additional teaching effort given our expanding student numbers.

When I arrived at Sussex three years ago the number of academic staff in the Department of Mathematics was just 15. We made a number of appointments in 2013 and these further posts will take it up to 25, which is still quite small by UK standards. Our strategic plan is to get staff numbers in Mathematics up to around 30 by 2018. In fact, applications by potential undergraduates to do Mathematics courses at Sussex are up by a whopping  80% this year, and if this turns into a large increase in intake then we will be looking to make further appointments very soon.

Please follow the links for more detailed descriptions of each job and further instructions on how to apply. The closing dates for all three jobs are 17th May 2016; we plan to interview selected candidates in June or July.

Feel free pass this on to likely applicants!

## In Praise of Student-Led Teaching Awards

Posted in Education with tags , , on March 2, 2016 by telescoper

Only time for a short post today. I was at a lunchtime meeting involving both staff and students in the School of Mathematical and Physical Sciences this lunchtime, and one item on the agenda was the University of Sussex student-led teaching awards scheme, which is run jointly by the University and the Student Union.

This reminded me of an article in last week’s Times Higher which argues that such awards are “divisive” and leave staff who don’t win such awards “demoralised”.

I suppose such awards are “divisive” in the sense that they divide staff into two categories: those that win and those that don’t. The same is true of any award. You might equally well argue that we shouldn’t award degrees to students on the grounds that some students get them and others don’t.

The negative feelings expressed about these awards seem to me to be more to do with sour grapes than with any genuine concern about the effect (or lack of effect) they might have on teaching quality. Staff who are upset that they don’t win an award would be better advised to learn from their more popular colleagues than expressing resentment towards them.

Another thing that annoys me about this criticism is that it assumes that it questions the motivations for students nominating lecturers; in particular that students pick lecturers who are “showy” or “entertaining” or who set easy examinations. In my opinion this assumption does a great disservice to students. Last year several staff in my School won such awards and it was quite clear that the students picked the staff concerned because they appreciated their approach to teaching, not that their courses were easier or for any other trivial reason. It’s more than a little arrogant for staff to assume that students aren’t qualified to comment on what teaching they like.

It’s over thirty years since I finished my undergraduate degree. In the intervening time the way students study at school and university has changed, partly because of new technology. I hear far too many lecturers demanding that students should learn the way they did when they were younger. We should always be looking for better ways of helping students learn, and I think student awards are one way of identifying examples of good practice.

So, to conclude, I think this complaint is tosh.

Feel free to disagree through the comments box!

## Preparing for a PhD Interview in Physics

Posted in Biographical, Education, The Universe and Stuff with tags , , , on February 1, 2016 by telescoper

The other day I was chatting to a group of our 4th-year MPhys students about the process for applying  (and hopefully being interviewed) for a PhD. This is the time when students in the UK have started to apply and are awaiting decisions on whether they have to go for an interview. Final decisions are usually made by the end of March so those with interviews have a busy couple of months coming up.

I actually quite enjoy doing PhD interviews, because that involves giving excellent young scientists their first step on the ladder towards a research career. I’m sure it’s not so pleasant for the candidates though. Nerves sometimes get the better of the students in these interviews, but experienced interviewers can calibrate for that. And if you’re nervous, it means that you care…

The question, in case you’re interested, was to estimate the angle through which light  is deflected by the Sun’s gravity. I hadn’t done any general relativity in my undergraduate degree, so just did it by dimensional analysis which is easy because an angle is dimensionless. That gets you within a factor of a two of the correct answer which, in those days, was pretty goood going for cosmology. That seemed to go down well and they offered me a place … which I turned down in favour of Sussex.

In those days, before detailed information about research in University departments was available online, the interview generally consisted of a discussion of the various projects available and a few odd questions about Physics (and possible Astronomy) to see if the candidate was able to think on their feet (i.e. without fainting).

Nowadays it’s a bit different. You can still expect a bit of questioning about undergraduate material but that is normally preceded by the chance to talk about your final-year project. One reason for that is that selectors are interested in project work because it can provide evidence of an aptitude for research. The other is simply that it gives the candidate a chance to get over any initial nerves by talking about something that they hopefully know well, as they will have been working on it for some time.

My first piece advice for students who have been offered an interview, therefore, is to prepare a short (~10 minute) verbal summary of your project work so you’re not wrong-footed if asked to talk about it.

Students nowadays are also expected to know a bit more about the thesis topic in advance, so my second tip is to  read up a bit of background so you can talk reasonably intelligently about the proposed research. If, for example, you have decided to work on Dark Energy (as many seem to these days), you won’t come across very well if you don’t know what the main issues are. What’s the observational evidence? What kind of theories are there? What are the open questions? Same goes for other fields. It also will do no harm if you read a couple of recent papers by your prospective supervisor, for reasons of flattery if nothing else.

Anyway, I think those are the two main things. If anyone has other advice to offer prospective PhD students, please feel free to add via the comments box.

## A Question of Magnitude

Posted in Cute Problems, Education, The Universe and Stuff with tags , , , on January 30, 2016 by telescoper

A frequent complaint raised by students of Astronomy is that astronomers insist on using funny units. Chief among them is the use of magnitudes to quanitify the brightness of an object. Why not use the observed intensity (or brightness or flux) of the light from the star, which can be expressed straightforwardly in SI units, instead of faffing around with a clunky logarithmic measure? The reason we use the magnitude scale is primarily historical and based on the fact that the eye’s response to light is more-or-less logarithmic and that in the days before calculators it was easier to deal with very large and very small numbers using logarithms.Most relevant calculations involve divisions and multiplications which become subtractions and additions when you use logarithmic quantities.

It was Norman Pogson who first suggested that a magnitude scale be defined such that a difference of five magnitudes should correspond to a factor of 100 in actual brightess. This was because the brightest naked-eye stars – those of first magnitude – are about 100 times brighter than the faintest naked-eye stars, which are of sixth magnitude. That was in 1856 and we’ve been stuck with it ever since!

Although the magnitude system may appear strange, it’s not really that hard to use when you get used to it. A beginner really just needs to know a few key things:

1.  Bright things have lower magnitudes (e.g. first magnitude stars are brighter than second magnitude stars);
2.  If two stars have apparent magnitudes $m_1$ and $m_2$ respectively then $m_2-M_1=2.5\log_{10} (I_1/I_2)$ where $I_1$ and $I_2$ are respectively the fluxes received from the two stars;
3. The intensity of light falls off with the square of the distance from the source;
4.  The absolute magnitude is the apparent magnitude a star would have if it were 10 parsecs from the observer;
5. Most stars have roughly black-body spectra so their total intrinsic luminosity depends on the product of their surface area (i.e. on the square of the radius) and the fourth power of the surface temperature.

Got it?

To test your understanding you could try these little problems. To warm up you might look at I posted the first of them a while ago. Anyway, here we go:

1. A binary system at a distance of 100 pc has such a small separation between its component stars that it is unresolved by a telescope. If the apparent visual magnitude of the combined image of the system is 10.5, and one star is known to have an absolute visual magnitude of 9.0, what is the absolute visual magnitude of the other star?
2. Two stars are observed to have the same surface temperature, but their apparent visual magnitudes differ by 5. If the fainter star is known to be twice as far away as the brighter one, what is the ratio of the radii of the two stars?
3. A binary system consists of a red giant star and a main-sequence star of the same intrinsic luminosity. The red giant has a radius 50 times that of the main-sequence star. (i) If the main-sequence star has a surface temperature of 10,000 K, what is the surface tempature of the red giant star? (ii) If the two stars can’t be resolved the combined system has an apparent magnitude of 12, what are the apparent magnitudes the two component stars would have if they could be observed separately?

Answers through the comments box please! The first correct entry wins a year’s free subscription to the Open Journal of Astrophysics…

1. Absolute magnitude 5.54 (apparent magnitude 10.54)
2. 5:1
3. (i) ~1400K (ii) 12.75, 12.75

## Physics & Astronomy at Sussex – The Videos!

Posted in Brighton, Education with tags , , on January 20, 2016 by telescoper

So the annual University admissions cycle is getting into gear, which means I’ll be spending quite a few Saturdays giving talks and chatting to prospective students and their parents. As we prepare for  the first of Applicant Visit Days at the University of Sussex (on Saturday 23rd January) we’ve produced a number of videos featuring current students in the Department of Physics & Astronomy. I thought I’d share a couple here.

First here’s Anjelah, a student on our 4-year MPhys degree in Theoretical Physics. She still seems quite keen, despite having taken my Theoretical Physics module in her second year!

Here’s Joe, a 4-year MPhys (Physics) student:

And here’s another by Linn, who is on the BSc in Physics with Astrophysics degree:

You’ll notice that both of them talk about our dedicated study spaces, which the students really like. We’re one of the few Physics & Astronomy Departments in the UK – in fact the only that I know of – that has turned over the management of a large suite of rooms over to our students. We don’t just allow them to use the rooms 24 hours a day; we also give them a budget for furniture and books and they basically decide what they want and how to arrange it all. We also provide a constant supply of free tea and coffee (although I have to admit that I do pop in there from time to time and help myself too).