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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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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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Generational Guilt

Posted in Biographical, Education, Politics with tags , , , , , , on November 23, 2012 by telescoper

Exhausted near the end of an exceptionally busy week, I found myself taking a short break after a two-hour lecturing session when a student knocked at my door to ask for some advice about applying for PhDs. I was happy to oblige, of course, but after he’d gone it struck me how much tougher things are for today’s generation, compared with how easy it was for me.

I got a scholarship to the local grammar school (The Royal Grammar School in Newcastle upon Tyne) by passing the 11+ examination back in 1974. I got a good education that most pupils at the School had to pay for (or at least their parents did). I got good 0 and A levels, and then passed the post A-level examination to get me into Cambridge. Through contacts at school I got a job for nine months working for a British Gas research station in Cramlington, during which time I earned a nice wage. I went to Cambridge with a healthy bank balance on top of which I received a full maintenance grant. There were no tuition fees then either. When I graduated I was solvent and debt-free.

When I applied for PhDs I did so with no real idea about what research I might do. I wasn’t an outstanding undergraduate student and my personal statement was vagueness personified, but I got a place nonetheless. The stipend was modest, but one could live on it. I never had money worries as a PhD. Nor have I since. It all seems so simple, looking back.

Today’s students have no such luck. The Direct Grant system that paid my school fees was discontinued shortly after I benefited from it. I’m sure I wouldn’t have got into University had I gone to the local comprehensive. Then maintenance grants were discontinued and fees introduced (then rapidly increased from £1000 to first £3000 and then £9000). Graduates now are usually burdened with huge debts. Moreover, when students apply for postgraduate study are nowadays often expected to not only to know precisely what they’re going to do but also be outstandingly good

The pressure we put on graduates now is out of all proportion to what I experienced. The reason? There are more of them overall, so there are more with first-class degrees chasing PhD funding. Many students who are much better than I was at the same stage of my career won’t make it just because of the arithmetic. Many will be discouraged by the finances too. It’s tragic that talented young people should be denied the chance to fulfil their ambitions by not having wealthy parents.

I’m often impressed (and even inspired) by those students who show a determination to pursue academic ambitions despite all the difficulties, but at the same time I feel guilty that it was so much easier in my day. Mine is the generation that decided to transfer the cost of higher education onto students and their families. Mine is also the generation that wrecked the economy by living beyond our means for too long.

To all those young people whose ambitions are thwarted by circumstances beyond their control all I can say is I’m sorry we oldies stole your future.

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In the Dark on Youtube

Posted in Education with tags , , , on November 12, 2012 by telescoper

Once again I find myself too busy to do a substantial post this lunchtime. However, I’ve been rescued by  Prof.  Philip Moriarty who tipped me off about the following video from the series “Sixty Symbols” which features this blog in a supporting a role as a source of old examination papers. The theme is the dire state of mathematics education in British schools, something I’ve moaned about on many occasions myself, so I thought I’d post it here. You’ll get a flash of my organ  about 6 minutes and 15 seconds  into the clip, so if you don’t want to see it please watch with your eyes closed.

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Three Tips for Solving Physics Problems

Posted in Cute Problems, Education with tags , , , , , on November 2, 2012 by telescoper

I spent quite some time this morning going over some coursework problems with my second-year Physics class. It’s quite a big course – about 100 students take it – but I mark all the coursework myself so as to get a picture of what  the students are finding easy and what difficult. After returning the marked scripts I then go through general matters arising with them, as well as making the solutions available on our on-line system called Learning Central.

Anyway, this morning I decided to devote quite a bit of time to some tips about how to tackle physics problems, not only in terms of how to solve them but also how to present the answer in an appropriate way.

I began with the Feynman algorithm for solving physics problems:

  1. Write down the problem.
  2. Think very hard.
  3. Write down the answer.

That may seem either arrogant or facetious, or just a bit of a joke, but that’s really just the middle bit. Feynman’s advice on points 1 and 3 is absolutely spot on and worth repeating many times to an audience of physics students.

I’m a throwback to an older style of school education when the approach to solving unseen mathematical or scientific problems was emphasized much more than it is now. Nowadays much more detailed instructions are given in School examinations than in my day, often to the extent that students  are only required to fill in blanks in a solution that has already been mapped out.

I find that many, particularly first-year, students struggle when confronted with a problem with nothing but a blank sheet of paper to write the solution on. The biggest problem we face in physics education, in my view, is not the lack of mathematical skill or background scientific knowledge needed to perform calculations, but a lack of experience of how to set the problem up in the first place and a consequent uncertainty about, or even fear of, how to start. I call this “blank paper syndrome”.

In this context, Feynman’s advice is the key to the first step of solving a problem. When I give tips to students I usually make the first step a bit more general, however. It’s important to read the question too.

The middle step is more difficult and often relies on flair or the ability to engage in lateral thinking, which some people do more easily than others, but that does not mean it can’t be nurtured.  The key part is to look at what you wrote down in the first step, and then apply your little grey cells to teasing out – with the aid of your physics knowledge – things that can lead you to the answer, perhaps via some intermediate quantities not given directly in the question. This is the part where some students get stuck and what one often finds is an impenetrable jumble of mathematical symbols  swirling around randomly on the page.

Everyone gets stuck sometimes, but you can do yourself a big favour by at least putting some words in amongst the algebra to explain what it is you were attempting to do. That way, even if you get it wrong, you can be given some credit for having an idea of what direction you were thinking of travelling.

The last of Feynman’s steps  is also important. I lost count of the coursework attempts I marked this week in which the student got almost to the end, but didn’t finish with a clear statement of the answer to the question posed and just left a formula dangling.  Perhaps it’s because the students might have forgotten what they started out trying to do, but it seems very curious to me to get so far into a solution without making absolutely sure you score the points.  IHaving done all the hard work, you should learn to savour the finale in which you write “Therefore the answer is…” or “This proves the required result”. Scripts that don’t do this are like detective stories missing the last few pages in which the name of the murderer is finally revealed.

So, putting all these together, here are the three tips I gave to my undergraduate students this morning.

  1. Read the question! Some solutions were to problems other than that which was posed. Make sure you read the question carefully. A good habit to get into is first to translate everything given in the question into mathematical form and define any variables you need right at the outset. Also drawing a diagram helps a lot in visualizing the situation, especially helping to elucidate any relevant symmetries.
  2. Remember to explain your reasoning when doing a mathematical solution. Sometimes it is very difficult to understand what you’re trying to do from the maths alone, which makes it difficult to give partial credit if you are trying to the right thing but just make, e.g., a sign error.
  3.  Finish your solution appropriately by stating the answer clearly (and, where relevant, in correct units). Do not let your solution fizzle out – make sure the marker knows you have reached the end and that you have done what was requested.

There are other tips I might add – such as checking answers by doing the numerical parts at least twice on your calculator and thinking about whether the order-of-magnitude of the answer is physically reasonable – but these are minor compared to the overall strategy.

And another thing is not to be discouraged if you find physics problems difficult. Never give up without a fight. It’s only by trying difficult things that you can improve your ability by learning from your mistakes. It’s not the job of a physics lecturer to make physics seem easy but to encourage you to believe that you can do things that are difficult.

So anyway that’s my bit of “reflective practice” for the day. I’m sure there’ll be other folk reading this who have other tips for solving mathematical and scientific problems, in which case feel free to add them through the comments box.

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Credentialism and Overexamination

Posted in Biographical, Education with tags , , , , , , , , on September 30, 2012 by telescoper

Only time for a quick post this morning as I have to go into the department to get my things ready for tomorrow, when the Autumn Semester starts and I have to begin lecturing (at 9am on a Monday morning). Anyway, the text for today’s sermon is provided by Ed Smith’s Left Field column in the New Statesman, the latest issue of which I read yesterday. His topic is the rise of credentialism and the resulting excessive amount of examination in the British school system:

It is now widely accepted that British pupils are excessively over-examined. Teachers are so busy focussing on examinations that there is little time left for education. Exam-led cramming has become the year-round norm – like an election campaign that consumes the whole political cycle. Exams are obviously necessary. But there is an optimal amount of assessment and it has been far exceeded. Grade inflation – notwithstanding this year’s controversial “crackdown” – is simply accepted as a fact.

It’s well said, and it’s not just the school system that suffers from disproportionate emphasis on assessment over education. It’s rife throughout the university system too, starting with the reliance on A-level grades as criteria for assessing students’ suitability for university study, through the “modular” undergraduate degree programmes with examinations twice a year for three or four years.

We examine far too frequently and the effect of this has been to turn the entire education system into a meaningless exercise in box-ticking.

It is an unfortunate irony: in our age of credentialism, exams have never mattered more. And yet they have never been more unreliable as gauges of academic quality.

I’ve felt for some time that in my discipline, Physics (and Astronomy) A-levels are virtually useless as indicators of the suitability of a student for doing an undergraduate degree. Some of the very best students I’ve ever had the pleasure to teach came into my university with modest A-level scores; and some students who came in with perfect grades at school never adjusted to the different, more independent type of study required of an undergraduate.

As Ed Smith points out, the increased emphasis on examination grades hasn’t expanded opportunity either.  It may appear to be fairer to base university entrance or award jobs on examination results rather than, say, interviews, but this has just led to a system that can be easily gamed – private tutors, cramming, re-sits to improve grades, and so on. He rightly concludes that the “correlation between exam results and intelligence has been steadily weakening”.

So what’s the alternative? Smith mentions the admissions process at Harvard University, which famously ignores high-school grades and relies on its own interview system. Interviews can be very biased if carried out in an inappropriate way. Subjecting a young person to a 30-minute grilling  in a room with a complete stranger can be enormously stressful for applicants who are shy, and would also play into the hands of those whose educational background has involved specific training for such ordeals. But one thing I’ve found by talking to students face-to-face is that it doesn’t take very long to identify precisely those things that the examination system does not: imagination, enthusiasm for the subject,  and a flair for thinking on your feet:

One teacher told me with regret that she had to advise her most academic pupil not to display her full intellectual range: in order to secure all the ticks, first you have to stop thinking freely.

If you don’t believe this, take a look at this GCSE Science Examination. A truly intelligent student would struggle to find any correct answer for many of the questions on that paper!

This is why we still place so much emphasis on interviews in the postgraduate admissions system: we take it for granted that all applicants for PhD places will have good undergraduate degrees. What marks out an excellent candidate for a position as  research student, however, is not the ability to pass exams but a mixture of creative flair and almost obsessive determination to surmount the difficult challenges involved in independent research. The correlation between these characteristics and degree results is by no means strong.

The problem for a UK University in adopting the Harvard approach is that credentialism is now running the system. Students apply to universities largely on the basis of their predicted A-level grades, lowering their sights if their predicted grades would not be expected to get them into a more “presitigious” department. But departments that take in students with low A-level scores also get marked down in the league tables for taking in “weaker” students. We’re all aware that A-levels are basically useless, but both sides are  bound so tightly into the system that there seems to be no escape.

So what’s the answer? I don’t know if there is one, but I’d love to see what would happen if all universities abandoned A-levels and instead set their own entrance examinations and interviews. It would be a huge amount of work, but it would make a refreshing change if universities could gather useful information rather than relying on the uninformative guff produced by the national examination boards.

And here is Smith’s closing remark that rings very true to me for personal reasons,

There is a further dimension to the problem of credentialism. It encourages life’s winners to underestimate their good fortune and to over-rate the extent to which they deserve their success. Far from advancing talent over privilege, credentialism has strengthened the grip of people already at the top.

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Blowing Smoke

Posted in Education, The Universe and Stuff with tags , , , , on July 18, 2012 by telescoper

I’ve been trying to make myself useful over the last few days thinking about the new module I’m supposed to start teaching in October. I’m a bit daunted by it to be honest. The title is The Physics of Fields and Flows and it will be taken by students when they return to start their second year after the summer break.  It’s twice the size of our usual modules, which means a lot of teaching and it’s all new for me, which means a lot of preparation.

The idea behind introducing this module was to teach a number of things together which previously had been taught in separate modules, specifically electromagnetism and vector calculus, or not at all, e.g. fluid mechanics. I’m not sure when or why classical fluid mechanics dropped out the syllabus, but I think it’s an essential part of a physics curriculum in its own right and also helps develop a physical understanding of the mathematics used to describe electric and magnetic fields. It’s one of the unhappy side-effects of modular teaching that it hides the important underlying connections between apparently disparate phenomena which are the essence of what physics is about.

Another thing I reckon we don’t do enough of these days is use lecture demonstrations. That’s harder to do these days because we tend to use pooled lecture theatres that don’t have the specialist equipment that they might have if they were dedicated to physics lectures only.  Practical demonstrations are now usually given second-hand, by using video clips.  That’s fine, but not as good as the real thing.

Anyway, it struck me that it would be quite easy to arrange a demonstration of the transition between laminar and turbulent flow using the simple and relatively inexpensive equipment shown in the rather beautiful image. Unfortunately, however, demonstrating this sort of thing isn’t allowed on University premises even for scientific purposes…

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More Order-of-Magnitude Physics

Posted in Cute Problems, Education with tags , , , on June 27, 2012 by telescoper

A very busy day today so I thought I’d just do a quick post to give you a chance to test your brains with some more order-of-magnitude physics problems. I like using these in classes because they get people thinking about the physics behind problems without getting too bogged down in or turned off by complicated mathematics. If there’s any information missing that you need to solve the problem, make an order-of-magnitude estimate!

Give  order of magnitude answers to the following questions:

  1. What is the tension in a violin string?
  2. By how much would the temperature of the Earth increase if all its rotational energy were converted to heat?
  3. What fraction of the Earth’s water is in its atmosphere?
  4. How much brighter is sunlight than moonlight?
  5. What is the mass of water in a soap bubble?

There’s no prize involved, but feel free to post answers through the comments box. It would be helpful if you explained a  bit about how you arrived at your answer!

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Gove Agreement

Posted in Education, Politics, Uncategorized with tags , , , on June 25, 2012 by telescoper

I’ve had the same worry about finding myself in agreement with Michael Gove, at least on a few things; see here, for example. Anyway, this piece makes some very good points about the corruption of the GCSE system.

Michael de Podesta's avatarProtons for Breakfast

What do you do when someone with whom you basically disagree, says something sensible? Michael Gove has placed me in this situation three times now.

Firstly he abolished the Qualifications and Curriculum development Authority (QCDA).  Secondly he pointed out at that school IT lessons are at best uninspiring. And now he has gone and acknowledged that our system of competitive exam boards has driven down GCSE standards.

You may not have noticed this because he also called for GCSEs to be replaced with ‘O’levels. I sympathise with his motivation – to raise the bar for the most academically able pupils – but I think he is wrong on this. It would be enormously disruptive, enormously divisive, and there is actually nothing inherently wrong with GCSEs.

The problem with GCSEs lies in the ‘almost corrupt‘ link between publishers and their ‘pet’ exam boards. The BBC…

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Teaching Physics

Posted in Education, The Universe and Stuff with tags , , on March 22, 2012 by telescoper

More on this weeks’ theme, from the inestimable xkcd…

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