Archive for Physics

Essays in Physics

Posted in Biographical, Education with tags , , , , , , on March 6, 2015 by telescoper

In the course of a rare episode of tidying-up in my office I came across this. You can click on it to make it bigger if it’s difficult to read. It was the first paper of my finals examination at the University of Cambridge way back in 1985. Yes, that really was thirty years ago…

wpid-wp-1425648226410.jpeg

As you can probably infer from the little circle around number 4, I decided to write an Essay about topic 4. I’ve always been interested in detective stories so this was an easy choice for me, but I have absolutely no idea what I wrote about for three hours. Nor do I recall actually ever getting a mark for the essay, so I never really knew whether it really counted for anything. I do remember, however, that I had another 3-hour examination in the afternoon of the same day, two three-hour examinations the following day, and would have had two the day after that had I not elected to do a theory project which let me off one paper at the end.

I survived this rigorous diet of examinations (more-or-less) and later that year moved to Sussex to start my DPhil, returning here couple of years ago as Head of the same School in which I did my graduate studies. To add further proof that the universe is cyclic, this year I’ve taken on the job of being External Examiner for physics at the University of Cambridge, the same place I did my undergraduate studies.

Anyway, to get back to the essay paper, we certainly don’t set essay examinations like that here in the Department of Physics & Astronomy at the University of Sussex and I suspect they no longer do so in the Department of Physics at Cambridge. I don’t really see the point of making students write such things under examination conditions. On the other hand, I do have an essay as part of the coursework in my 2nd Year Theoretical Physics module. That may seem surprising and I’m not sure the students like the idea, but the reason for having it is that theoretical physics students don’t do experimental work in the second year so they don’t get the chance to develop their writing skills through lab reports. The essay titles I set are much more specific than those listed in the paper above and linked very closely to the topics covered in the lectures, but it’s still an opportunity for physics students to practice writing and getting some feedback on their efforts. Incidentally, some of the submissions last year were outstandingly good and I’m actually quite looking forward to reading this year’s crop!

What is the Scientific Method?

Posted in The Universe and Stuff with tags , , on February 25, 2015 by telescoper

Twitter sent me this video about the scientific method yesterday, so I thought I’d share it via this blog.

The term Scientific Method is one that I find it difficult to define satisfactorily, despite having worked in science for over 25 years. The Oxford English Dictionary  defines Scientific Method as

..a method or procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.

This is obviously a very general description, and the balance between the different aspects described is very different in different disciplines. For this reason when people try to define what the Scientific Method is for their own field, it doesn’t always work for others even within the same general area. It’s fairly obvious that zoology is very different from nuclear physics, but that doesn’t mean that either has to be unscientific. Moreover, the approach used in laboratory-based experimental physics can be very different from that used in astrophysics, for example. What I like about this video, though, is that it emphasizes the role of uncertainty in how the process works. I think that’s extremely valuable, as the one thing that I think should define the scientific method across all disciplines is a proper consideration of the assumptions made, the possibility of experimental error, and the limitations of what has been done. I wish this aspect of science had more prominence in media reports of scientific breakthroughs. Unfortunately these are almost always presented as certainties, so if they later turn out to be incorrect it looks like science itself has gone wrong. I don’t blame the media entirely about this, as there are regrettably many scientists willing to portray their own findings in this way.

When I give popular talks about my own field, Cosmology,  I often  look for appropriate analogies or metaphors in television programmes about forensic science, such as CSI: Crime Scene Investigation which I used to watch quite regularly (to the disdain of many of my colleagues and friends). Cosmology is methodologically similar to forensic science because it is generally necessary in both these fields to proceed by observation and inference, rather than experiment and deduction: cosmologists have only one Universe;  forensic scientists have only one scene of the crime. They can collect trace evidence, look for fingerprints, establish or falsify alibis, and so on. But they can’t do what a laboratory physicist or chemist would typically try to do: perform a series of similar experimental crimes under slightly different physical conditions. What we have to do in cosmology is the same as what detectives do when pursuing an investigation: make inferences and deductions within the framework of a hypothesis that we continually subject to empirical test. This process carries on until reasonable doubt is exhausted, if that ever happens. Of course there is much more pressure on detectives to prove guilt than there is on cosmologists to establish “the truth” about our Cosmos. That’s just as well, because there is still a very great deal we do not know about how the Universe works.

 

 

Funding for Masters in Science

Posted in Education with tags , , , , , , , , on February 11, 2015 by telescoper

My recent post about postgraduate scholarships at the University of Sussex has generated quite a lot of interest so I thought I’d spend a few moments today trying to answer some of the questions I’ve been asked recently, by current and prospective students (or parents thereof).

I’ll start by explaining what the difference is between the different forms of Masters degrees in science that you can get in the United Kingdom, chiefly the distinction between an MSc  and one of the variations on the MPhys or MMath we have here in the School of Mathematical and Physical Sciences here at the University of Sussex. I have to admit that it’s all very confusing so here’s my attempt to explain.

The main distinction is that the MSc “Master of Science” is a (taught) postgraduate (PG) degree, usually of one (calendar) year’s duration, whereas the MPhys etc are undergraduate (UG) degrees usually lasting 4 years. This means that students wanting to do an MSc must already have completed a degree programme (and usually have been awarded at least Second Class Honours)  before starting an MSc whereas those doing the MPhys do not.

Undergraduate students wanting to do Physics in the Department of Physics & Astronomy at the University of Sussex, for example, can opt for either the 3-year BSc or the 4-year MPhys programmes. However, choosing the 4-year option does not lead to the award of a BSc degree and then a subsequent Masters qualification;  graduating students get a single qualification usually termed an “integrated Masters”.

It is possible for a student to take a BSc and then do a taught MSc programme afterwards, perhaps at a different university, but there are relatively few MSC programmes for Physics  in the UK because the vast majority of students who are interested in postgraduate study will already have registered for 4-year undergraduate programmes. That’s not to say there are none, however. There are notable MSc programmes dotted around, but they tend to be rather specialist; examples related to my own area include Astronomy and Cosmology at Sussex and Astrophysics at Queen Mary. Our own MSc in Frontiers in Quantum Technology is the only such course in the United Kingdom.

To a large extent these courses survive by recruiting students from outside the UK because the market from home students is so small. No department can afford to put on an entire MSc programme for the benefit of just one or two students. Often these stand-alone courses share modules with the final year of the undergraduate Masters, which also helps keep them afloat.

So why does it matter whether one Masters is PG while the other is UG? One difference is that the MSc lasts a calendar year (rather than an academic year). In terms of material covered, this means it contains 180 credits compared to the 120 credits of an undergraduate programme. Typically the MSc will have 120 credits of taught courses, examined in June as with UG programmes, followed by 60 credits worth of project work over the summer, handed in in September, though at Sussex some of our programmes are split 90 credits coursework and 90 credits of project.

The reason why this question comes up so frequently nowadays is that the current generation of applicants to university (and their parents) are facing fees of £9K per annum. The cost of doing a 3-year BSc is then about £27K compared to £36K for an MPhys. When rushing through the legislation to allow universities to charge this amount, the Powers That Be completely forgot about PG programmes, which have accordingly maintained their fees at a relatively low level, despite the fact that these are not controlled by government. For example, the MSc Astronomy at Sussex attracts a fee of about £6K for home students and £17K for overseas students. These levels are roughly consistent with the UG fees paid by  home students on the previous fee regime (approx £3.5K per annum, bearing in mind that you get 1.5 times as much teaching on an MSc compared to a year of an MPhys).

Being intelligent people, prospective physicists look at the extra £9K they have to pay for the 4th year of an MPhys and compare it with the current rate for an entire MSc and come to the conclusion that they should just do a BSc then switch. This seems to be not an unreasonable calculation to make.

However, there are some important things to bear in mind. Firstly, unlike UG programmes, the fee for PG programmes is basically unregulated. Universities can charge whatever they like and can increase them in the future if they decide to. See, for example, the list at Sussex University which shows that MSc fees already vary by more than a factor of four from one school to another. Incidentally, that in itself shows the absurdity of charging the same fee for UG degrees regardless of subject…

Now the point is that if one academic year of UG teaching costs £9K for future students, there is no way any department can justify putting on an entire calendar of advanced courses (i.e. at least 50% more teaching at an extremely specialist level) for less than half the  income per student. Moreover undergraduate courses in laboratory-based sciences attract an additional contribution of around £1.4K (“the unit of resource”) paid by the government to the University concerned via HEFCE.  The logical fee level for MSc programmes is mininum of about 1.5 times the UG fee, plus the unit of resource applied to full calendar year, which is a whopping £15.6K (similar to the current whopping amount already paid by overseas students for these programmes). It’s therefore clear that you cannot take the current MSc fee levels as a guide to what they will be in three years’ time, when you will qualify to enter a taught PG programme. Prices will certainly have risen by then. I doubt if there will be a sudden step-change, but they will rise.

The picture has changed significantly since the Chancellor of the Exchequer announced in the Autumn Statement last year that loans of up to £10,000 would be made available to students on postgraduate (Masters) courses from 2016/17 onwards.  Welcome though this scheme may be it does not apply to students wanting to start a Masters programme this September (i.e. for Academic Year 2015/16).

I’d say that, contrary to what many people seem to think,  if you take into the full up-front fee and the lack of student loans etc, the cost of a BSc + MSc is  already significantly greater than doing an MPhys, and in future the cost of the former route will inevitably increase. I therefore don’t think this is a wise path for most Physics undergraduates to take, assuming that they want their MSc to qualify them for a career in Physics research, either in a university or a commercial organization, perhaps via the PhD degree, and they’re not so immensely rich that money is no consideration.

The exception to this conclusion is for the student who wishes to switch to another field at Masters level,  to do a specialist MSc in a more applied discipline such as medical physics or engineering. Then it might make sense, as long as you can find a way to deal with the need to pay up-front for such courses.

Now comes the plug for Sussex. Last week the University of Sussex unveiled a huge  boost to the University’s flagship Chancellor’s Masters Scholarships means that 100 students graduating this summer with a first-class degree from any UK university will be eligible to receive a £10,000 package (non-repayable)  to study for a Masters degree at Sussex. There are also specific schemes to support students who are already at Sussex; see here.

I’m drawing this to the attention of readers of this blog primarily to point out that the Department of Physics & Astronomy at the University of Sussex is one of relatively few UK universities to have a significant and well-established programme of Masters (MSc) courses, including courses in Physics, Particle Physics,  Cosmology, and Astronomy. In particular, as I mentioned above, we are the only Department in the United Kingdom to have an MSc in Quantum Technology, an area which has just benefitted from a substantial cash investment from the UK government.

Wisely, the University of Sussex has introduced special measures to encourage current Integrated Masters students to stay on their degree rather than bailing out into a BSc and taking a Masters. However, this scheme is a great opportunity for high-flying physics graduates from other universities to get a funded place on any of our MSc programmes to start later this year. Indeed, the deal that is being offered is so good that I would recommend students who are currently in the third year of 4-year MPhys or MSci integrated Masters programmes, perhaps at a dreary University in the Midlands, to consider ditching  your current course, switching to a BSc and graduating in June in order to take up this opportunity. The last year of an integrated Masters consists of 120 credits of material for which you will have to be a further £9K of fees; a standalone Masters at Sussex would involve 180 credits and be essentially free if you get a scholarship.

Think about it, especially if you are interested in specializing in Quantum Technology. Sussex is the only university in the UK where you can take an MSc in this subject! This is a one-off opportunity, since (a) this scheme will be replaced by loans from 2016/17 and (b) the fees will almost certainly have risen by next year for the reasons I outlined above.

In conclusion, though, I have to say that, like many other aspects of Higher Education in the Disunited Kingdom, this system is a mess. I’d prefer to see the unified system of 3 year UG Bachelor degrees, 2-year Masters, and 3-year PhD that pertains throughout most of continental Europe.

P.S. In the interest of full disclosure, I should point out an even worse anomaly. I did a 3-year Honours degree in Natural Science at Cambridge University for which I was awarded not a BSc but a BA (Bachelor of Arts). A year or so later this – miraculously and with no effort on my part – turned into an MA. Work that one out if you can.

Helping Blind Physicists

Posted in Education with tags , , , , on February 4, 2015 by telescoper

The Department of Physics & Astronomy at the University of Sussex has been supporting some fantastic research into the accessibility of science education. Daniel Hajas, a blind second year physics undergraduate student has been working with Dr. Kathy Romer, Reader in Astrophysics, on a research project related to innovative assistive technology.

Daniel came up with the idea of an audio-tactile graphics display (TGD) that should allow representation of graphical information in audio and tactile modalities, mostly focusing on figures used in mathematical sciences such as graphs, geometric shapes etc. The TGD is a device  with approximate dimensions of a tablet that can sit on a table top and can be connected with a PC using either a wired or wireless solution.

During the summer of 2014, Daniel wrote a research proposal, attended an assistive technology oriented conference and since the beginning of this academic year has been searching for partners/funding. Daniel and Kathy recently submitted an application to the Inclusive Technology Price (ITP).

Since October they have made contact with IT and cognitive science experts from the Sussex IT department and are also in contact with an LHC Sound project (CERN) team member to assist with sonification. Daniel and Kathy plan to establish collaboration with experts from various fields, find research partners and funding. Such an interdisciplinary research requires collaboration of various Sussex Departments if not other Universities from across the UK.

Daniel's 3D Vector Board

Daniel’s 3D Vector Board

Daniel has also been busy inventing the ‘3D vector board’, a small plastic board with two flexible rubber stripes perpendicular to each other which can be can moved around such that they show the axes of a coordinate system. The board has a grid on it with 1×1 cm squares. At the junctions four little holes are drilled in the corner of the squares. This allows the vectors (metal sticks of different length) to be fixed on the board. Since there are horizontal, diagonal and vertical sticks i.e. the sticks are either in the plane, perpendicular to or in an angle respect to the plane of the board 3D vector scenarios can be modelled easily.

Although Daniel intended to use the board solely for his own purposes, feedback suggests this relatively simple tool could be used efficiently in education for demonstrational purposes. Both visually impaired and sighted students could benefit from it. Sketches on paper or black boards only allow 2D representations. The 3D vector board might also work well in illustrating aims of the TGD project. Although the main goal is to develop a very advanced high-tech assistive device over a period of years, Daniel and Kathy might also come up with a number of low-tech ideas to improve accessibility of mathematical sciences for visually impaired students.

See Daniel’s project website for further details about his research.

R.I.P. Charles Townes, the physicist whose work touched all our lives

Posted in The Universe and Stuff with tags , , , , on January 28, 2015 by telescoper

Just a short post to mark the passing of a truly great physicist, Charles H. Townes, who died yesterday at the age of 99.

Charles Townes, pictured in 2013

Charles Townes, pictured in 2013

Townes came to fame for his pioneering work on the theory and applications of the maser , which he then followed up by designing the first laser. Lasers are used in many common consumer devices such as optical disk drives, laser printers, barcode scanners and fibre-optic cables. They are also used in medicine for laser surgery and various skin treatments, and in industry for cutting and welding materials.

The work of Charles Townes in physics has thus had an enormous impact on everyday life; he was awarded the Nobel Prize for is his work on quantum electronics, especially lasers and masers.

It’s very sad that he didn’t quite make his century, especially because this year is the International Year of Light, which will involve many activities and celebrations relating to his work on lasers. Much of our experimental work in Physics here in the Department of Physics and Astronomy at the University of Sussex involves lasers in various ways, and we will find an appropriate occasion to celebrate the life and achievements of a truly great physicist. Until then let me just express my condolences to the friends, family and colleagues of Charles Townes on the loss not only of an eminent scientist but of an extremely nice man.

R.I.P. Charles Townes, physicist and gentleman (1915-2015).

The Map is not the Territory

Posted in History, The Universe and Stuff with tags , , , , , , , , on January 27, 2015 by telescoper

I came across this charming historical map while following one of my favourite Twitter feeds “@Libroantiguo” which publishes fascinating material about books of all kinds, especially old ones. It shows the location of London coffee houses and is itself constructed in the shape of a coffee pot:

Coffee
Although this one is obviously just a bit of fun, maps like this are quite fascinating, not only as practical guides to navigating a transport system but also because they often stand up very well as works of art. It’s also interesting how they evolve with time  because of changes to the network and also changing ideas about stylistic matters.

A familiar example is the London Underground or Tube map. There is a fascinating website depicting the evolutionary history of this famous piece of graphic design. Early versions simply portrayed the railway lines inset into a normal geographical map which made them rather complicated, as the real layout of the lines is far from regular. A geographically accurate depiction of the modern tube network is shown here which makes the point:

tubegeo

A revolution occurred in 1933 when Harry Beck compiled the first “modern” version of the map. His great idea was to simplify the representation of the network around a single unifying feature. To this end he turned the Central Line (in red) into a straight line travelling left to right across the centre of the page, only changing direction at the extremities. All other lines were also distorted to run basically either North-South or East-West and produce a regular pattern, abandoning any attempt to represent the “real” geometry of the system but preserving its topology (i.e. its connectivity).  Here is an early version of his beautiful construction:

Note that although this a “modern” map in terms of how it represents the layout, it does look rather dated in terms of other design elements such as the border and typefaces used. We tend not to notice how much we surround the essential things, which tend to last, with embellishments that date very quickly.

More modern versions of this map that you can get at tube stations and the like rather spoil the idea by introducing a kink in the central line to accommodate the complexity of the interchange between Bank and Monument stations as well as generally buggering about with the predominantly  rectilinear arrangement of the previous design:

I quite often use this map when I’m giving popular talks about physics. I think it illustrates quite nicely some of the philosophical issues related with theoretical representations of nature. I think of theories as being like maps, i.e. as attempts to make a useful representation of some  aspects of external reality. By useful, I mean the things we can use to make tests. However, there is a persistent tendency for some scientists to confuse the theory and the reality it is supposed to describe, especially a tendency to assert there is a one-to-one relationship between all elements of reality and the corresponding elements in the theoretical picture. This confusion was stated most succintly by the Polish scientist Alfred Korzybski in his memorable aphorism :

The map is not the territory.

I see this problem written particularly large with those physicists who persistently identify the landscape of string-theoretical possibilities with a multiverse of physically existing domains in which all these are realised. Of course, the Universe might be like that but it’s by no means clear to me that it has to be. I think we just don’t know what we’re doing well enough to know as much as we like to think we do.

A theory is also surrounded by a penumbra of non-testable elements, including those concepts that we use to translate the mathematical language of physics into everday words. We shouldn’t forget that many equations of physics have survived for a long time, but their interpretation has changed radically over the years.

The inevitable gap that lies between theory and reality does not mean that physics is a useless waste of time, it just means that its scope is limited. The Tube  map is not complete or accurate in all respects, but it’s excellent for what it was made for. Physics goes down the tubes when it loses sight of its key requirement: to be testable.

In any case, an attempt to make a grand unified theory of the London Underground system would no doubt produce a monstrous thing so unwieldly that it would be useless in practice. I think there’s a lesson there for string theorists too…

Now, anyone for a game of Mornington Crescent?

 

That Was The REF That Was..

Posted in Finance, Science Politics with tags , , , , , , on December 18, 2014 by telescoper

I feel obliged to comment on the results of the 2014 Research Excellence Framework (REF) that were announced today. Actually, I knew about them yesterday but the news was under embargo until one minute past midnight by which time I was tucked up in bed.

The results for the two Units of Assessment relevant to the School of Mathematical and Physical Sciences are available online here for Mathematical Sciences and here for Physics and Astronomy.

To give some background: the overall REF score for a Department is obtained by adding three different components: outputs (quality of research papers); impact (referrring to the impact beyond academia); and environment (which measures such things as grant income, numbers of PhD students and general infrastructure). These are weighted at 65%, 20% and 15% respectively.

Scores are assigned to these categories, e.g. for submitted outputs (usually four per staff member) on a scale of 4* (world-leading), 3* (internationally excellent), 2* (internationally recognised), 1* (nationally recognised) and unclassified and impact on a scale 4* (outstanding), 3* (very considerable), 2* (considerable), 1* (recognised but modest) and unclassified. Impact cases had to be submitted based on the number of staff submitted: two up to 15 staff, three between 15 and 25 and increasing in a like manner with increasing numbers.

The REF will control the allocation of funding in a manner yet to be decided in detail, but it is generally thought that anything scoring 2* or less will attract no funding (so the phrase “internationally recognised” really means “worthless” in the REF, as does “considerable” when applied to impact). It is also thought likely that funding will be heavily weighted towards 4* , perhaps with a ratio of 9:1 between 4* and 3*.

We knew that this REF would be difficult for the School and our fears were born out for both the Department of Mathematics or the Department of Physics and Astronomy because both departments grew considerably (by about 50%) during the course of 2013, largely in response to increased student numbers. New staff can bring outputs from elsewhere, but not impact. The research underpinning the impact has to have been done by staff working in the institution in question. And therein lies the rub for Sussex…

To take the Department of Physics and Astronomy, as an example, last year we increased staff numbers from about 23 to about 38. But the 15 new staff members could not bring any impact with them. Lacking sufficient impact cases to submit more, we were obliged to restrict our submission to fewer than 25. To make matters worse our impact cases were not graded very highly, with only 13.3% of the submission graded 4* and 13.4% graded 3*.

The outputs from Physics & Astronomy at Sussex were very good, with 93% graded 3* or 4*. That’s a higher fraction than Oxford, Cambridge, Imperial College and UCL in fact, and with a Grade Point Average of 3.10. Most other departments also submitted very good outputs – not surprisingly because the UK is actually pretty good at Physics – so the output scores are very highly bunched and a small difference in GPA means a large number of places in the rankings. The impact scores, however, have a much wider dispersion, with the result that despite the relatively small percentage contribution they have a large effect on overall rankings. As a consequence, overall, Sussex Physics & Astronomy slipped down from 14th in the RAE to 34th place in the REF (based on a Grade Point Average). Disappointing to say the least, but we’re not the only fallers. In the 2008 RAE the top-rated physics department was Lancaster; this time round they are 27th.

I now find myself in a situation eerily reminiscent of that I found myself facing in Cardiff after the 2008 Research Assessment Exercise, the forerunner of the REF. Having been through that experience I’m a hardened to disappointments and at least can take heart from Cardiff’s performance this time round. Spirits were very low there after the RAE, but a thorough post-mortem, astute investment in new research areas, and determined preparations for this REF have paid dividends: they have climbed to 6th place this time round. That gives me the chance not only to congratulate my former colleagues there for their excellent result but also to use them as an example for what we at Sussex have to do for next time. An even more remarkable success story is Strathclyde, 34th in the last RAE and now top of the REF table. Congratulations to them too!

Fortunately our strategy is already in hand. The new staff have already started working towards the next REF (widely thought to be likely to happen in 2020) and we are about to start a brand new research activity in experimental physics next year. We will be in a much better position to generate research impact as we diversify our portfolio so that it is not as strongly dominated by “blue skies” research, such as particle physics and astronomy, for which it is much harder to demonstrate economic impact.

I was fully aware of the challenges facing Physics & Astronomy at Sussex when I moved here in February 2013, but with the REF submission made later the same year there was little I could do to alter the situation. Fortunately the University of Sussex management realises that we have to play a long game in Physics and has been very supportive of our continued strategic growth. The result of the 2014 REF result is a setback but it does demonstrate that the stategy we have already embarked upon is the right one.

Roll on 2020!

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