Archive for theoretical physics

Exam Time

Posted in Education, Maynooth with tags , , , on January 12, 2020 by telescoper

Back in Maynooth into the January examination period, I await the arrival tomorrow of the first batch of examination scripts I have to mark, so I thought I’d do a quick post on the topic of examinations.

First, for readers elsewhere, full-time undergraduate students at Maynooth what is called 60 “credits” in a year, usually split into two semesters of thirty credits each. This is usually split into 5-credit modules with an examination in each module at the end of each semester. Projects, and other continuously-assessed work do not involve a written examination, but the system means that a typical student will have at least 5 written examination papers in January and at least another 5 in May. Each examination is usually of two hours’ duration.

This is very similar to the system in most UK universities that I am aware of except that a full year’s work over there is 120 credits so there’s a conversion factor of 2:1. A 5-credit module in Ireland would be a 10-credit module in the United Kingdom, for example, but otherwise the system is similar.

One big difference between our examinations in Theoretical Physics in Maynooth and those at other institutions I’ve taught at in the UK is that the papers here – at least at a reasonably advanced level, say Years 3 and 4 – offer no choice of questions to be answered.  A typical format for a two-hour paper is that there are two long questions, each of which counts for 50 marks. Elsewhere  one normally finds students have a choice of two or three questions from four or five on the paper.

One  advantage of our system is that it makes it much harder for students to question-spot in the hope that they can get a good grade by only revising a fraction of the syllabus. If they’re well designed, two long questions can cover quite a lot of the syllabus for a module, which they have to in order to test all the learning outcomes. To accomplish this, questions can be split into parts that may be linked to each other to a greater or lesser extent to explore the connections between different ideas, but also sufficiently separate that a student who can’t do one part can still have a go at others. With such a paper, however, it is a  dangerous strategy for a student to focus only on selected parts of the material in order to pass.

As an examiner, the Maynooth style of examination also has the advantage that you don’t have to worry too much if one question turns out to be harder than the others. That can matter if different students attempt different questions, but not if everyone has to do everything.

But it’s not just the number of questions that’s important, it’s the duration. I’ve never felt that it was even remotely sensible for undergraduate physics examinations to be a speed test, which was often the case when I was a student. Why the need for time pressure? It’s better to be correct than to be fast, I think. I always try to set examination questions that could be done inside two hours by a student who knew the material, including plenty of time for checking so that even a student who made a mistake would have time to correct it and get the right answer. If a student does poorly in this style of examination it will be because they haven’t prepared well enough rather than because they weren’t fast enough.

The structure of the Maynooth examinations at more introductory level is rather different, with some choice. In my first year module on Mechanics & Special Relativity, for example, there is a compulsory first question worth 50 marks (split into several pieces) and then the students can pick two out of three shorter questions worth 25 marks each. This is a somewhat gentler approach than with the more advanced papers, partly adopted because we have quite a few students doing the General Science degree who taking Mathematical Physics as one of their 4 first-year subjects but will not be taking it further.

As their examination is not until Wednesday, I’ll have to wait until later this week to find out how my first-years have done. This will be the examination taken at University level for most of my class, so let me take this opportunity to pass on a few quick tips.

  1. Try to get a good night’s sleep before the examination and arrive in plenty of time before the start.
  2. Read the entire paper before starting to answer any questions. In particular, make sure you are aware of any supplementary information, formulae, etc, given in the rubric or at the end.
  3. Start off by tackling the question you are most confident about answering, even if it’s not Question 1. This will help settle any nerves.
  4. Don’t rush! Students often lose marks by making careless errors. Check all your numerical results on your calculator at least twice and – PLEASE – remember to put the units!
  5. Don’t panic! You’re not expected to answer everything perfectly. A first-class mark is anything over 70%, so don’t worry if there are bits you can’t do. If you get stuck on a part of a question, don’t waste too much time on it (especially if it’s just a few marks). Just leave it and move on. You can always come back to it later.

Readers of this blog are welcome to add other tips through the comments box below!

Oh, and good luck to anyone at Maynooth or elsewhere taking examinations in the next few weeks!

 

Theoretical Physics at Maynooth University Open Days!

Posted in Education, Maynooth with tags , on November 30, 2019 by telescoper

Today, Saturday 30th November 2019, is another Open Day at Maynooth University.

I used to give Open Day talks quite frequently in a previous existence as Head of School of Mathematical and Physical Sciences at the University of Sussex and now I’m at it again, giving talks on behalf of the Department of Theoretical Physics.

If you’re coming along today, please say hello either at the lecture (2.10pm)) or at the stall in the Iontas Building from 10.30 each day where you can chat about the course or anything else vaguely related to Theoretical Physics. There are other stalls, of course, but the Theoretical Physics one is obviously way more interesting than the others!

I might have time to take a few snaps during the day. If I do I’ll post them here. In the meantime here is a summary of my talk:

UPDATE: I didn’t get time to take any pictures because we were busy all morning. The subject talk in the afternoon was absolutely packed out – way more people than I’ve seen at any other open days here at Maynooth – and loads of questions at the end. Very enjoyable but rather exhausting. I think I might head home for a nap!

Open Day Friday

Posted in Biographical, Maynooth with tags , , , on November 29, 2019 by telescoper

It’s a busy day today in Maynooth with two very important jobs to do. Until lunchtime I’ll be preoccupied with an Open Day here at Maynooth University, the first of this year’s cycle. Here’s the poster advertising them (with dates included):

You’ll see that I have a new role as Poster Boy for Maynooth University, though they have understandably put me at the extreme edge of the poster (bottom right). I’ve got plenty of people helping on the stall in the Iontas Building today but I do have to give a talk to prospective students. There’s another Open Day tomorrow, for which I’ll be on the stall and doing the talk for most of the day.

Here’s a little promotional video:

Today’s  Open Day winds down by 2pm after which my second major task of the day begins. But that’s a secret, at least for the time being.

 

 

 

The Theoretical Physics Equipment Store

Posted in Education, The Universe and Stuff with tags , on November 22, 2019 by telescoper

This door, deep in the bowels of the Department of Theoretical Physics at Maynooth University, leads to a cupboard in which we keep all the equipment used in our Theoretical Physics lectures:

The door is not numbered as a security precaution because of the high value of the items contained in the cupboard. This is foolproof measure because it is the only door in the Department without a number on it, and is therefore impossible to identify. It is here that you will find, among other things, some items I used in my first-year Mechanics lectures:

  • a supply of light inelastic string;
  • frictionless pulleys (various sizes);
  • rigid rods of various lengths;
  • a large array of point masses;
  • smooth inclined planes at various angles;
  • a collection of perfectly elastic spheres;
  • bottles containing a variety of incompressible fluids of negligible viscosity;
  • jars of ideal gas.

I’m mindful, however, that we may lack some items that are in regular use in Theoretical Physics departments elsewhere, perhaps for more advanced topics,  so if anyone has ideas for things to be added to this store please suggest them through the comments box so I can ensure that we have them in stock for next semester.

 

 

In Praise of Omnibus Science

Posted in Education, Maynooth with tags , , , on April 16, 2019 by telescoper

I’m taking a few days off at the moment so this morning I had a bit of time to catch up on various things. One news item I stumbled across points out that first-choice applications to study at Maynooth University are the highest ever. Within the overall increase of about 7% there is a growth of 17% in Science subjects, which is very good news for the Department of Theoretical Physics as well as the other Departments in the Faculty of Science and Engineering.

Anyway, this spurred me to comment on what I think is one of the strengths of Maynooth University: the Omnibus Science programme.

Currently, most students doing Science subjects here enter on the Omnibus programme, a four-year science course that involves doing four subjects in the first year, but becoming increasingly specialised thereafter. That’s not unlike the Natural Sciences course I did at Cambridge, except that students at Maynooth can do both Theoretical Physics and Experimental Physics in the first year as separate choices. Other possibilities include Chemistry, Computer Science, Biology, etc.

In Year 1 students do four subjects (one of which is Mathematics). That is narrowed down to three in Year 2 and two in Year 3. In their final year, students can stick with two subjects for a Joint Honours degree, or specialise in one, for Single Honours.

I like this programme because it does not force the students to choose a specialism before they have had a taste of the subject, and that it is flexible enough to accommodate Joint Honours qualifications in, e.g., Theoretical Physics and Mathematics. It also allows us to enrol students onto Physics degrees who have not done Physics as part of the Leaving Certificate.

I think it’s a strength that students take such a broad first year rather than locking themselves into one discipline from the start. Part of the reason is that I went to do my own degree at Cambridge expecting to end up specialising in Chemistry, but enjoyed the physics far more, eventually specialising in Theoretical Physics. I’m sure there were others who went the other way too!

One problem with the Omnibus Science programme is that the range of possible final qualifications is perhaps not as clearly advertised as it could be, so some clearer signposting would do no harm.

Theoretical Physics at Maynooth University Open Day!

Posted in Education, Maynooth with tags , on April 5, 2019 by telescoper

Well, tomorrow (Saturday 6th April)  is an Open Day at Maynooth University. If you want to find out more about it you can look here where you will find this video which has some nice views of the campus:

I used to give Open Day talks quite frequently in a previous existence as Head of School of Mathematical and Physical Sciences at the University of Sussex and now I’m at it again, giving a talk on behalf of the Department of Theoretical Physics this Open Day. If you come along, please come along to my talk (at 14.10 on Saturday)!

We also have a stall in the Iontas Building from 10.30, where you can meet staff and students and talk to them about the course, or anything else vaguely related to Theoretical Physics. There are other stalls, of course, but the Theoretical Physics one is obviously way more interesting than the others!

Looking for fun pictures to put in my talk I stumbled across this:

I think that’s the only one I need, really!

Physics: Mathematical or Theoretical or Experimental?

Posted in Education, Maynooth, The Universe and Stuff with tags , , , on November 26, 2018 by telescoper

Fresh from doing two Open Day talks last week I thought I’d write a few words here about something that cropped up in the question-and-answer session.

For a start, I should explain that here at Maynooth University there are two Physics departments, one the Department of Theoretical Physics (of which I am a Faculty member) and the other the Department of Experimental Physics. These two units are in the same building but are largely separate in terms of teaching and research.

For instance, when students enter on our General Science degree programme they have to choose four subjects in the first year, including Mathematics (much as I did when I did my Natural Sciences degree at Cambridge back in the day). Picking `double physics’ (i.e. Experimental Physics and Theoretical Physics) uses up two of those choices, whereas Physics was a single choice in the first year of my degree.

To confuse matters still further, the Department of Theoretical Physics only recently changed its name from the Department of Mathematical Physics and some of our documentation still carries that title. I got asked several times at the weekend what’s the difference between Theoretical Physics and Mathematical Physics?

As far as Maynooth is concerned we basically use those terms interchangeably and, although it might appear a little confusing at first, having both terms scattered around our webpages means that Google searches for both `Mathematical Physics’ and `Theoretical Physics’ will find us.

It’s interesting though that Wikipedia has different pages for Mathematical Physics and Theoretical Physics. The former begins

Mathematical physics refers to the development of mathematical methods for application to problems in physics. The Journal of Mathematical Physics defines the field as “the application of mathematics to problems in physics and the development of mathematical methods suitable for such applications and for the formulation of physical theories”. It is a branch of applied mathematics, but deals with physical problems.

while the latter starts

Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena.

The difference is subtle,and there is obviously a huge amount in common between these two definitions, but it is perhaps that Theoretical Physics is more focused on the use of mathematics to account for the results of experiment and observations whereas Mathematical Physics concerns itself more with the development of the necessary mathematical techniques, but I’m sure there will be readers of this blog who disagree with this interpretation.

For the record here is what Wikipedia says about Experimental Physics:

Experimental physics is the category of disciplines and sub-disciplines in the field of physics that are concerned with the observation of physical phenomena and experiments. Methods vary from discipline to discipline, from simple experiments and observations, such as the Cavendish experiment, to more complicated ones, such as the Large Hadron Collider.

I’d say that theoretical physicists are more likely than mathematical physicists to be working closely with experimentalists. I count myself as a theoretical physicist (that’s what I did in Part II at Cambridge, anyway) though I do work a lot with data.

Anyway, as an experiment, I asked the audience at my Open Day talks if they could name a famous physicist. Most popular among the responses were the names you would have guessed: Einstein, Hawking, Feynman, Dirac, Newton, Schrodinger, and some less familiar names such as Leonard Susskind and Brian Greene. Every single one of these is (or was) a theorist of some kind. This is confirmed by the fact that many potential students mention similar names in the personal statements they write in support of their university applications. For better or worse, it seems that to many potential students Physics largely means Theoretical (or Mathematical) Physics.

Although it is probably good for our recruitment that there are so many high-profile theoretical physicists, it probably says more about how little the general public knows about what physics actually is and how it really works. For me the important thing is the interplay between theory and experiment (or observation), as it is in that aspect where the whole exceeds the sum of the parts.

It might seem a bit strange to have two Physics departments in one University – though it seems to work alright in Cambridge! – but I think it works pretty well. The one problem is that there isn’t a clear entry point for `Physics’ without an adjective. Students can carry Theoretical Physics and Experimental Physics through all the way to final year and get a joint honours degree (50% theory and 50% experiment) or they can pick one to do single honours, but we might attract a few more students if the former possibility were just called `Physics’. Perhaps.