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Should the passive voice be avoided?

Posted in Education with tags , , , , , on May 1, 2013 by telescoper

It’s another very busy day (as well as another lovely one) so I thought instead of sitting indoors this lunchtime writing a typically verbose blog item I’d just pick something out of my back catalogue and give it another airing because it deals with something that’s come up a couple of times recently.

This is the time of year when final-year students are drafting their project reports. Yesterday I was back in Cardiff giving feedback on two such articles.  I usually quite enjoy reading these things, in fact. They’re not too long and I’m usually pretty impressed with how the students have set about the (sometimes quite tricky) things I’ve asked them to do for their project work. I think the project report is quite a challenge for UK physics students because they generally haven’t had much practice in putting together a lengthy piece of writing before or during their university course, so haven’t developed a style that they feel comfortable with and are often unfamiliar with various conventions (such as reference style, punctuation of equations, etc). Some of these are explained in quite a lot of detail in the instructions the students are given, of course, but we all know that only girls read instructions….

The thing that strikes me most forcibly about the strange way students write project reports is that they are nearly always phrased entirely in the passive voice, e.g.

The experiment was calibrated using a phlogiston normalisation widget….

I accept that people disagree about whether the passive voice is good style or not. Some journals actively encourage the passive voice while others go the opposite way entirely . I’m not completely opposed to it, in fact, but I think it’s only useful either when the recipient of the action described in the sentence is more important than the agent, or when the agent is unknown or irrelevant. There’s nothing wrong with “My car has been stolen” (passive voice) since you would not be expected to know who stole it. On the other hand “My Hamster has been eaten by Freddy Starr” would not make a very good headline.

The point is that the construction of a statement in the passive voice in English is essentially periphrastic, in that it almost inevitably involves some form of circumlocution – either using more words than necessary to express the meaning or being deliberately evasive by introducing ambiguity. Both of these failings should be avoided in scientific writing.

Apparently, laboratory instructors generally tell students to write their reports in the passive voice as a matter of course. I think this is just wrong. In a laboratory report the student should describe what he or she did. Saying what “was done” often leaves the statement open to the interpretation that somebody else did it. The whole point of a laboratory report is surely for the students to describe their own actions. “We calibrated the experiment..”  or “I calibrated the experiment…” are definitely to be preferred to the form I gave above.

That brings me to the choice of pronoun in the active voice. One danger is that it can appear very bombastic, but that’s not necessarily the case. I don’t find anything particularly wrong in saying, e.g.

We improve upon the technique of Jones et al. (1848) by introducing a variable doofer in the MacGuffin control, thereby removing gremlins from the thingummy process.

But the main issue is whether to use the singular or plural form. It can be irritating to keep encountering “I did this..” and “I did that..” all the way through a journal paper, and I certainly  would feel uncomfortable writing a piece like that in the first person singular. I think it feels less egotistical to use “we”, even if there is only one author (which is increasingly rare in any case). If it’s good enough for the Queen it’s good enough for me! However, I just looked “we” up in Chambers dictionary and found

..used when speaking patronizingly, esp to children, to mean `you’.

which wasn’t at all what I had in mind!

However in the case of a student project that I’m assessing I actually want to know what the particular student  writing the report did, not what was done by person or persons unspecified or by a group of uncertain composition. So I encourage my students to put, e.g.,

I wrote a computer program in 6502 Assembly Language to solve the Humdinger equation using the Dingbat-Schnitzelgruber algorithm.

I also (sometimes) like “we” when there’s, e.g., a complicated mathematical derivation.  Going  line by line through a lengthy piece or difficult technical argument seems friendlier if you imagine that the reader is trying to do the calculation along with you as you write it:

if we differentiate the right hand side of equation (8), use the expression for x obtained in equation (97), expand y in a power-series and take away the number we first thought of we find…

The “we” isn’t necessarily an  author with delusions of grandeur (or schizophrenia), but instead denotes a joint operation between author and reader.

Anyway, to resume the thread, it seems to me that sometimes it is appropriate to use the passive voice because it is the correct grammatical construction in the circumstances. Sometimes also the text just seems to work better that way too. But having to read an entire document written in the passive voice drives me to distraction. It’s clumsy and dull.

In scientific papers, things are a little bit different but I still think using the active voice makes them easier to read and less likely to be ambiguous. In the introduction to a journal paper it’s quite acceptable to discuss the background to your work in the passive voice, e.g. “it is now generally accepted that…” but when describing what you and your co-authors have done it’s much better to use the active voice. “We observed ABC1234 using the Unfeasibly Large Telescope..” is, to my mind, much better than “Observations of ABC1234 were made using..”.

Reading back over this post I notice that I have jumped fairly freely between active and passive voice, thus demonstrating that I don’t have a dogmatic objection to its use. What I’m arguing is that it shouldn’t be the default, that’s all.

My guess is that a majority of experimental scientists won’t agree with this opinion, but a majority of astronomers and theoreticians will.

This guess will now be tested by reactivating an old poll..

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Technical Support

Posted in Education with tags , , , on April 18, 2013 by telescoper

We’re approaching the end of term here at the University of Sussex and there are lots of things that need to get finished before then, so it’s a very busy day. Just time for a quick post to pass on some great news and a comment.

One of my colleagues when I worked in the School of Physics & Astronomy at Cardiff University, Steven Baker, has won an award for being the best STEM Technician in the category of Physical Sciences in the whole country! This is an new award set up by the Higher Education Academy, so Steven is the inaugural winner of it.  Although I suspect he won’t enjoy being the centre of attenti0n very much I’m very pleased that he won this award. Among many other things he was central in setting up the  gear that enabled current 4th-year Cardiff MPhys students to have a much wider selection of modules, by accessing lectures from Swansea University by video link.

I’m also delighted that this award has been set up generally because I feel very strongly that the contribution made by support staff in university departments.  No Physics department can run with out a dedicated crew of technicians who apply their expertise in both teaching and research laboratories, but there are many more people – clerical staff, computer officers, etc – without whom many of our activities would grind to a halt. None of these support staff gets the recognition they deserve; they are often poorly paid and lack an appropriate career structure that reflects the importance of the work they do.

So Steven’s award is an occasion not just for him to celebrate, but also to remind us academics that we couldn’t do what we do without people like him doing all the difficult stuff!

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Why participation isn’t widening

Posted in Education with tags , on March 23, 2013 by telescoper

Frustrated at my ongoing indisposition – I had to miss today’s Admissions Day at Sussex University, which has put me in a very bad mood – I’ve decided to deliver a short rant about widening participation. WP is the name given to schemes to open up access to higher education to students from less advantaged backgrounds. An excellent idea, of course.

The problem is that, despite pressure from the relevant quango (OFFA) most self-styled leading universities, especially those in the Russell Group, have consistently failed to widen participation to any significant extent. Why is this?

The easy answer is that universities have to take students who are adequately prepared for undergraduate studies, which means selecting on the basis of A-level grades, which means students from private schools have an advantage.

The problem with this argument is that, at least in Physics and Mathematics, I don’t think A-levels are a reliable indicator of aptitude for undergraduate study at all. If I had my way we wouldn’t use A-levels at all.

Unfortunately we’re stuck with the current, unfair, system because any “leading” university that takes a large number of students with weak A-levels (possibly through a Foundation Programme) will be penalised in the league tables for not being selective enough. Moreover, the Government’s decision to lift the cap on places for students with AAB or better, means that recruiting students with top A-level grades is potentially the most lucrative strategy.

That the system doesn’t work the way it is supposed to is obvious. If you don’t agree, then ask yourself why it’s not the case that virtually all Oxbridge students get first class degrees, when they admit only A*/A students?

Things won’t improve until we abandon the obsession with A-level tariff points and find a way of assessing intrinsic ability.

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Alma Mater

Posted in Biographical, Education with tags , on March 22, 2013 by telescoper

During my short visit to Cambridge on Wednesday I happened to pass through Magdalene College (on my way to a couple of pints in The Pickerel). I couldn’t resist taking a pic of the Lutyens Building, where I lived in the first year (1982/3). My room was second from the far end, on the first floor. I wonder who’s in there now?

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Your PhD Questions Answered (?)

Posted in Education, The Universe and Stuff with tags , , , , , , on March 10, 2013 by telescoper

As I mentioned last week, one of the main items on the agenda at the moment is recruitment of new PhD students. As usual, this finds me having to operate on both sides of the fence,  playing a role in selecting students whilst also trying to advise students on how to target their applications, prepare for interview, and choose between offers (for those who manage to get a place).

In my field (astrophysics), the primary route for funding a PhD comes through the Science and Technology Facilities Council (STFC) which operates a national deadline (31st March) before which candidates can not be required to make a decision. This deadline sets the timescale for departments to decide too, as we clearly want to make sure all our first choice applicants get their offers before the cutoff date.

The national deadline prevents students from being pressured into making decisions before they have heard back from all the institutions to which they have applied, so in that sense it’s a good idea. On the other hand, it does mean that there’s often frantic activity on deadline day as offers are accepted or declined. Reserves have to be contacted quickly when a favoured candidate withdraws to go somewhere else and not all of them may still be available. A student who has been waiting anxiously without a first-choice offer may suddenly receive a lifeline on deadline day.

Getting offers is one thing, but deciding between them is quite another. There are many things to take into account, and the criteria are by no means clear. I’m not the only person to have been thinking about this. There are personal matters, of course. Is it a nice place? Are the people friendly? Do you think you can get on with your potential supervisor? That sort of thing. But there’s also the actual research. Is the project really what you want to do? Is is likely to open up a future career in research, or just be a dead end? Is the mixture of theory and experiment (or observation) what you would like?

One of the issues that often arises when I discuss research with potential PhD students is how structured the project  is. Some projects are  mapped out by the supervisor in great detail, with specific things to be done in a specific order with well-defined milestones against which progress can be measured. Others, especially but not exclusively theoretical ones, are much more of the nature of “here’s an interesting idea – let’s study it and see where it leads”. Most PhDs are somewhere between these two extremes, but it’s probably true that experimental PhDs are more like the former, whereas theoretical ones are more like the latter. Mine, in theoretical astrophysics, ended up evolving quite considerably from its starting point.

I’ve always been grateful to my supervisor for allowing me the freedom to follow my own curiosity. But I think it was essential to be given an initial focus, in the form of a specific project to cut my teeth on. Getting a calculation finished, written up and published gave me the confidence to start out on my own, but I did need a lot of guidance during that initial phase. We a;ll need to learn how to walk before we can run.

Another aspect of this is what the final thesis should look like. Should it be a monolithic work, focussed on one very specific topic, or can it be an anthology of contributions across a wider area?  Again, it’s a question of balance. I think that a PhD thesis should be seen as a kind of brochure advertising the skills and knowledge of the student that produced it. Versatility is a good quality, so if you can do lots of different things then your thesis should represent that. On the other hand, you also need to demonstrate the ability to carry out a sustained and coherent piece of research. Someone who flits around knocking out lots of cutesy “ideas papers” may get a reputation for being a bit of a dabbler who is unable or unwilling to tackle problems in depth. The opposite extreme would be a person who is incapable of generating new ideas, but excellent once pointed in a specific direction. The best scientists, in my opinion, have creative imagination as well as technical skill and stamina.  It’s a matter of balance, and some scientists are more balanced than others. There are some (scary) individuals who are brilliant at everything, of course., but us mere mortals have to make the most of our limited potential.

The postdoc market that lies beyond your PhD is extremely tough. To survive you need to maximize the chances of getting a job, and that means being able to demonstrate a suitability for as many opportunities as possible that come up. So if you want to do theory, make sure that you know at least something about observations and data analysis. Even if you prefer analytic work, don’t be too proud to use a computer occasionally. Research problems often require  you to learn new things before you can tackle them. Get into the habit of doing that while you’re a student, and you’re set to continue for the rest of your career. But you have to do all this without spreading yourself too thin, so don’t shy away from the chunky calculations that keep you at your desk for days on end. It’s the hard yards that win you the match.

When it comes to choosing supervisors, my advice would be to look for one who has a reputation for supporting their students, but avoid those who want to exert excessive control. I think it’s a supervisor’s duty to ensure that PhD student becomes as independent as possible as quickly as possible, but to be there with help and advice if things go wrong. Sadly there are some who treat PhD students simply as assistants, and give little thought to their career development.

But if all this sounds a bit scary, I’ll add just one thing. A PhD offers a unique challenge. It’s hard work, but stimulating and highly rewarding. If you find a project that appeals to you, go for it. You won’t regret it.

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Sussex, a month in…

Posted in Biographical, Education, The Universe and Stuff with tags , , on March 2, 2013 by telescoper

Well, although it seems like no time at all it appears I’ve now been in Brighton and working at the University of Sussex for a whole month! Here’s a picture of the street I live in in the Kemptown area of Brighton, taken this afternoon. That’s the English Channel at the end of the road, in case you don’t know where Brighton is; it’s definitely not in the Midlands.

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I’m currently on campus again, although I made a major miscalculation in that Brighton and Hove Albion are playing at home again today. Since the Amex Stadium is just over the road from the University, that means I’ll either have to go back before the final whistle blows or wait until the crowds have dispersed before returning to base.

It has been unbelievably hectic. Although I knew it was going to be hard work taking over as Head of School halfway through the academic year, several unforeseen things have come up that have made me even busier than I’d anticipated. Some of these were pleasant surprises and some weren’t, but that’s all I’m going to say for now!

Since I arrived a large part of my time has been spent on matters relating to new staff appointments, arising from a mixture of replacements and new investment across the whole School of Mathematical and Physical Sciences. That has included new staff in Applied Mathematics, Theoretical Particle Physics, Experimental Particle Physics, Atomic, Molecular and Optical Physics and of course Astronomy. There are more to come over the next few weeks, including a new group in the area of Probability and Statistics. It’s pleasant work, of course, especially when it goes well (which it definitely is) but I have to admit that the schedule of presentations and interviews is rather exhausting.

Apart from that the other principle preoccupation has been strategic planning for the next five years. On Thursday morning I had a crunch meeting with members of the University’s management team to discuss the plans for MPS, which were actually drafted before I took up my post but have since been modified quite a bit. I was more nervous before that meeting than I’ve been for many years, primarily because I did not know what to expect. It turned out to be quite pleasant, actually, and I left the meeting not only relieved but relaxed.

In the afternoon it was back to interviewing, but this time for postgraduate students. That’s also a pleasant duty, because it 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…

Anyone reading this who is nervous about doing a PhD interview (or has experienced nerves in one they’ve already had) might reflect on my experience when I was called to interview for a PhD place in Astronomy at the University of Manchester way back in 1985. I was very nervous before that, and arrived very early for my grilling. I was told to wait in a sort of ante-room as the previous interview had only just started. I started to read a textbook I had brought with me. About five minutes later, the door of the interview room opened and the interviewers, Franz Kahn and John Dyson, carried out the unconscious body of the previous candidate. It turned out that, after a couple of friendly preliminary questions, the two Professors had handed the candidate a piece of chalk and told him to go to the blackboard  to work something out, at which point said candidate had fainted. When it was my turn to be handed the chalk I toyed with the idea of staging a mock swoon, but resisted the temptation.

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. That seemed to go down well and they offered me a place … which I turned down in favour of Sussex.

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Omnibus Edition

Posted in Biographical, Education with tags , , , , on February 27, 2013 by telescoper

One of the things I’ve had to get used to about working at a University based on an out-of-town campus is that it’s no longer feasible to walk to work every morning. Fortunately there is an excellent bus service from central Brighton to Falmer, so this isn’t too much of a hardship. I’ve now invested in one of those new-fangled smart cards that makes it very economical not only for getting to work, but also for hopping on and off while pottering about town doing shopping and whatnot.

I have noticed that if I get the No. 25 bus from Old Steine before 8am it only takes about fifteen minutes to get to the University of Sussex. If I’m a bit late starting out, however, and don’t get to the bus stop until after eight in the morning, the trip can take about forty minutes. The problem is that roadworks on the A27 Lewes Road have reduced it to a single lane in each direction; there’s a critical point when the traffic builds up to rush hour levels and then solidifies. Still, I don’t mind getting in before 9am as that gives me useful time before the roll of meetings commences, so I found it quite easy to adapt to the early start.

Anyway sitting on the bus this morning I had a kind of flashback to my schooldays. The school I went to was on the opposite side of Newcastle to where I lived, so I had to take the bus every morning. I did much the same thing in those days as I am doing now, in fact – getting the bus at 7.30 to avoid the heaviest traffic, and often doing the previous night’s homework before lessons started in the morning.

The one thing that was very different in those days (and we’re talking about the Seventies now) was that the “School Run” didn’t really exist. Even the posh kids took the bus or train to School rather than being ferried back and forth by doting parents. I think it did me a lot of good travelling on the bus along with all kinds of other people rather than being transported in the hermetically sealed cocoon of a family car. The famous friendliness of Tyneside folk undoubtedly contributed to the omnibus experience and left me with a lifelong preference for public over private transport. I’ve never owned a car and have no intention of ever doing so.

Anyway, this all reminds me of the (probably apocryphal) quote from Margaret Thatcher:

A man who, beyond the age of 26, finds himself on a bus can count himself as a failure.

Whilst I’d by no means be ashamed to be counted a failure according to a Thatcherite criterion, I did once get a bit riled by a version of it when I was conducting a UCAS Admissions Day at another institution (also a campus university). A (male) parent of one of the candidates asked me why there was so little car parking space for students on the campus. I replied that undergraduates were basically not allowed to park on the campus, otherwise it would be overrun with motor vehicles and wouldn’t be so nice and spacious and green. However, I said, that’s not a problem because there was an excellent bus service that could take students to the University from town and vice versa in just a few minutes. The indignant father bristled and announced in a very loud and angry voice “No son of mine is going to get on a bus”. That was the nearest I’ve ever come to losing my temper with a parent on a university admissions day. Fortunately nothing like it has happened since.

It never would have occurred to my parents to come with me when I visited universities for interview and I would have been horrified if they had insisted on doing so. Nowadays, however, prospective students are invariably accompanied by parents, who generally ask at least as many questions as their offspring do. Is this just an extension of the School Run, or is because parents now have to foot the bill (when in my day there were maintenance grants and no tuition fees). Either way, times have definitely changed.

Anyway, I’m about to get the bus home. Tomorrow we are interviewing prospective postgraduate (PhD) students. I don’t think any will bring their parents along. And quite a few may even come on the bus.

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Advice for Prospective Physics Students

Posted in Education with tags , , , , , , , on February 25, 2013 by telescoper

Just got time for a quickie this morning before I head up to the Big Smoke for the first meeting of the Astronomy Grants Panel of the Science and Technology Facilities Council (STFC). I had thought that the last round would be my last, but I must have misbehaved somehow and my sentence has been extended accordingly.

Anyway, I thought I’d follow up Saturday’s post with a response to a question that a few prospective Physics students asked me during our Admissions Day. Those attending these days have already applied to this University but, at this stage of the annual undergraduate admissions cycle, the applicants are still deciding which University to put as their first or firm choice. I see our job in the Admissions Days simply to make available as much information as possible to the applicants to help them make a choice. Quite a few people I spoke to on Saturday, however, said that they had already made up their minds and just wanted some advice about what to do during the summer after they have finished their A-levels to help them prepare for their undergraduate studies in Physics (and/or Astronomy).

The answer I gave was pretty simple: practice your mathematics, especially your calculus! 

The justification for exhortation is that the big difference between Physics at A-level and Physics at undergraduate University level is that the latter is taught in a much more mathematical way than the former. This is because the physical laws that underpin our understanding of the natural world are expressed in a mathematical language; the more fluent you are in this language the easier you will find it to assimilate the physical concepts. To put it another way, you will find it difficult to understand the physical meaning of what is being taught if you are struggling with the mathematical meaning of the symbols being used or the manipulations needed to obtain useful solutions to the relevant equations.

Newton’s Second Law, for example,  relates the rate of change of momentum of a body to the force exerted upon it. If you’re comfortable with calculus you don’t think twice about writing d(mv)/dt for the rate of change of momentum and then constructing a differential equation which you can (hopefully) solve. You won’t absorb the importance of laws like this unless you become so familiar with the mathematics that it ceases to occupy the part of your mind that’s needed to really think.

I think that learning to do Physics is a bit like learning to play a musical instrument. Practicing such basic mathematical procedures as integration and differentiation is analogous to the five-finger exercises you have to do when learning to play the piano. The more you practice them, the greater the extent to which they become hard-wired. Your brain can therefore concentrate on the more interesting conceptual stuff – that’s really the hard part of learning Physics. We do of course do as much as we can to help with this once you’ve got to University, but doing some preparation on your own beforehand would greatly smooth the transition.

So I’d tell any prospective physics student wondering what to do this summer to get hold of as many basic calculus exercises as they can and do them whenever they get the chance. It may not be the most exciting way to spend your post A-level holiday, but it is the single thing you can do that will best prepare you for life as a Physics student.

On the other hand, the advice I’d give to physicists rather later in their careers is to think very carefully before agreeing to be on committees or panels…

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Open for Mathematics, Physics, Astronomy (and Astrophysics)…

Posted in Education, The Universe and Stuff with tags , , , , , , , , on February 23, 2013 by telescoper

I’ve been here on campus at the University of Sussex all day helping out with an Admissions Day. We were all a bit apprehensive in the School of Mathematical and Physical Sciences about today simply because so many students and guests were scheduled to come that we wondered how well we could organize the large number of groups being shown around. There was also the question of the British weather. It was very cold this morning, with flurries of snow as I made my way to campus. I was wondering whether the weather might put some people off travelling, but as it happened we had a lot of visitors and although we were very busy there was a very good buzz about the place.

Notwithstanding the inclement weather this morning there are also definite signs that spring is on the way:

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Anyway, it was nice to have the chance to talk to prospective students and parents in both Mathematics and Physics & Astronomy. Although Mathematics, Physics and Astronomy are combined within the School, there are clear distinctions between the way Mathematics and Physics are taught so the topics discussed with Mathematics students tended to be different from those in Physics and Astronomy. However, a chat with one group led eventually to the question What’s the difference between Astronomy and Astrophysics? This is something I’m asked quite often, and have blogged about before, but I thought I’d repeat it here for those who might stumble across it.

The Oxford English Dictionary gives the following primary definition for astronomy:

The science which treats of the constitution, relative positions, and motions of the heavenly bodies; that is, of all the bodies in the material universe outside of the earth, as well as of the earth itself in its relations to them.

Astrophysics, on the other hand, is described as

That branch of astronomy which treats of the physical or chemical properties of the celestial bodies.

So astrophysics is regarded as a subset of astronomy which is primarily concerned with understanding the properties of stars and galaxies, rather than just measuring their positions and motions.

It is possible to assign a fairly precise date when astrophysics first came into use in English because, at least in the early years of the subject, it was almost exclusively associated with astronomical spectroscopy. Indeed the OED gives the following text as the first occurence of astrophysics, in 1869:

As a subject for the investigations of the astro-physicist, the examination of the luminous spectras of the heavenly bodies has proved a remarkably fruitful one

The scientific analysis of astronomical spectra began with a paper by   William Hyde Wollaston in the Philosophical Transactions of the Royal Society Vol. 102, p. 378, 1802. He was the first person to notice the presence of dark bands in the optical spectrum of the Sun. These bands were subsequently analysed in great detail by Joseph von Fraunhofer in a paper published in 1814 and are now usually known as Fraunhofer lines.  Technical difficulties  made it impossible to obtain spectra of stars other than the Sun for a considerable time, but  William Huggins finally succeeded in 1864. A drawing of his pioneering spectroscope is shown below.

Meanwhile, fundamental work by Gustav Kirchoff and Robert Bunsen had been helping  to establish an understanding of the spectra produced by hot gases.  The identification of features in the Sun’s spectrum  with similar lines produced in laboratory experiments led to a breakthrough in our understanding of the Universe whose importance shouldn’t be underestimated. The Sun and stars were inaccessible to direct experimental test during the 19th Century (as they are now). But spectroscopy now made it possible to gather evidence about their chemical composition as well as physical properties. Most importantly, spectroscopy provided definitive evidence that the Sun wasn’t made of some kind of exotic unknowable celestial material, but of the same kind of stuff (mainly Hydrogen) that could be studied on Earth.  This realization opened the possibility of applying the physical understanding gained from small-scale experiments to the largest scale phenomena that could be seen. The science of astrophysics was born.

One of the leading journals in which professional astronomers and astrophysicists publish their research is called the Astrophysical Journal, which was founded in 1895 and is still going strong. The central importance of the (still) young field of spectroscopy can be appreciated from the subtitle given to the journal:

Initially the branch of physics most important to astrophysics was atomic physics since the lines in optical spectra are produced by electrons jumping between different atomic energy levels. Spectroscopy of course remains a key weapon in the astrophysicist’s arsenal but nowadays the term astrophysics is taken to mean any application of physical laws to astronomical objects. Over the years, astrophysics has therefore gradually incorporated nuclear and particle physics as well as thermodynamics, relativity and just about every other branch of physics you can think of.

I realise, however, that this  isn’t really the answer to the question that potential students want to ask. What they (probably) want to know is what is the difference between undergraduate courses called Astronomy and those called Astrophysics? The answer to this one depends very much on where you want to study. Generally speaking the differences are in fact quite minimal. You probably do a bit more theory in an Astrophysics course than an Astronomy course, for example. Your final-year project might have to be observational or instrumental if you do Astronomy, but might be theoretical in Astrophysics.  If you compare the complete list of modules to be taken, however, the difference will be very small.

Over the last twenty years or so, most Physics departments in the United Kingdom have acquired some form of research group in astronomy or astrophysics and have started to offer undergraduate degrees with some astronomical or astrophysical content. My only advice to prospective students wanting to find which course is for them is to look at the list of modules and projects likely to be offered. You’re unlikely to find the name of the course itself to be very helpful in making a choice.

One of the things that drew me into astrophysics as a discipline (my current position is Professor of Theoretical Astrophysics as well as being Head of School) is that it involves such a wide range of techniques and applications, putting apparently esoteric things together in interesting ways to develop a theoretical understanding of a complicated phenomenon. I only had a very limited opportunity to study astrophysics during my first degree as I specialised in Theoretical Physics.  This wasn’t just a feature of Cambridge. The attitude in most Universities in those days was that you had to learn all the physics before applying it to astronomy. Over the years this has changed, and most departments offer some astronomy right from Year 1.

I think this change has been for the better because I think the astronomical setting provides a very exciting context to learn physics. If you want to understand, say, the structure of the Sun you have to include atomic physics, nuclear physics, gravity, thermodynamics, radiative transfer and hydrostatics all at the same time. This sort of thing makes astrophysics a good subject for developing synthetic skills while more traditional physics teaching focusses almost exclusively on analytical skills.

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The Quantum of Teaching

Posted in Education with tags , , , , on February 19, 2013 by telescoper

I’m gradually finding out enough about the way things are organized here at the University of Sussex to make some comparisons between teaching in the School of Mathematical and Physical Sciences here and in the School of Physics and Astronomy at my former employer, Cardiff University.

One difference I’ve noticed is probably something you find rather trivial, but I think it’s quite important. In the usual scheme of undergraduate teaching, which applies across most of the United Kingdom, students gain “credit” for taking and passing modules. A normal year would correspond to 120 credits, so that a three-year BSc degree involves a total of 360 credits and a four-year MPhys (or equivalent) is 480. In universities that run a two-semester teaching year the load per semester is thus 60 credits.

The question then is what is the best way to divide up that 60 credits into smaller pieces? Until recently at Cardiff the basic unit of teaching was a 10-credit module, which meant that students were typically doing six different things alongside each other. An ordinary ten-credit module would involve two lectures per week. Not all of these are lecture courses, however; there’s usually laboratory or computational work as one of the 10 credit chunks. During a recent course review it was decided to increase the size of some of the modules to 20 credits. That’s how it came to pass that I taught a new module of that size last semester (for the first and last time).

The motivation for increasing the size of modules was twofold. One is that having lots of small modules makes the overall study programme disjointed and “bitty”, with students having lots of things on the go at the same time and little opportunity to study any topics in real depth. The other is that having four hours per week instead of two allows the lecturer to use the time more flexibly, in particular with  sessions intended to develop problem-solving skills.

Although the “core” modules at Cardiff increased to 20 credits, the others remained at 10. There was a lot of discussion about increasing all modules, but in the end the new programme was left as a mixture.

Interestingly, here at Sussex the normal module size is 15 credits (and “modules” are also called “courses”), meaning that students actually only do four things at the same time in a typical semester.  In fact this was what I originally suggested when we started the teaching review at Cardiff, but it was thrown out immediately on the grounds that the University had decreed that modules must be multiples of 10 credits only. I’m not sure whether there was an educational reason for this, or just that it made the arithmetic simpler.

Anyway, I like 15 credits as a basic unit but am not sure how many other Schools and Departments run that system. I’d be interested to learn about module sizes favoured elsewhere through the comments box, and here’s a poll so you can vote:

Another difference is that although Sussex has two teaching semesters, the School of Mathematical and Physical Sciences (MPS) does not have mid-year examinations, so First Semester courses are examined in the Summer along with the Second Semester ones.  In Cardiff, modules are examined at the end of the semester in which they are taught. There are pros and cons with this. I think students who are used to mid-year examinations like the fact that the examinations are not all concentrated in one period during the summer and also that they get some feedback on their progress during the year. On the other hand, students may see an end-of-semester examination as an encouragement to close the lid on a particular module and forget about it as soon as it is over, making it harder to understand how different aspects of physics interconnect.

Students at Sussex seem keen not to have mid-year examinations, while those at Cardiff seem equally keen to retain them. I don’t know what that means, so here’s another  poll to see if there’s any clear opinion one way or another among my readers…

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