Tag Archives: Teaching

Summer days, academics and technological universities

The heatwave in the northern hemisphere may (or may not) be an ominous portend of things to come, but it’s certainly making for an enjoyable summer here in Ireland. I usually find it quite difficult to do any meaningful research when the sun is out, but things are a bit different when the good weather is regular.  Most days, I have breakfast in the village, a swim in the sea before work, a swim after work and a game of tennis to round off the evening. Tough life, eh.




                                       Counsellor’s Strand in Dunmore East

So far, I’ve got one one conference proceeding written, one historical paper revamped and two articles refereed (I really enjoy the latter process, it’s so easy for academics to become isolated). Next week I hope to get back to that book I never seem to finish.

However, it would be misleading to portray a cosy image of a college full of academics beavering away over the summer. This simply isn’t the case around here – while a few researchers can be found in college this summer, the majority of lecturing staff decamped on June 20th and will not return until September 1st.

And why wouldn’t they? Isn’t that their right under the Institute of Technology contracts, especially given the heavy teaching loads during the semester? Sure – but I think it’s important to acknowledge that this is a very different set-up to the modern university sector, and doesn’t quite square with the move towards technological universities.

This week, the Irish newspapers are full of articles depicting the opening of Ireland’s first technological university, and apparently, the Prime Minister is anxious our own college should get a move on. Hmm. No mention of the prospect of a change in teaching duties, or increased facilities/time for research, as far as I can tell (I’d give a lot for an office that was fit for purpose).  So will the new designation just amount to a name change? And this is not to mention the scary business of the merging of different institutes of technology. Those who raise questions about this now tend to get cast as dismissed as resistors of progress. Yet the history of merging large organisations in Ireland hardly inspires confidence, not least because of a tendency for increased layers of bureaucracy to appear out of nowhere – HSE anyone?

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A festschrift at UCC

One of my favourite academic traditions is the festschrift, a conference convened to honour the contribution of a senior academic. In a sense, it’s academia’s version of an Oscar for lifetime achievement, as scholars from all around the world gather to pay tribute their former mentor, colleague or collaborator.

Festschrifts tend to be very stimulating meetings, as the diverging careers of former students and colleagues typically make for a diverse set of talks. At the same time, there is usually a unifying theme based around the specialism of the professor being honoured.

And so it was at NIALLFEST this week, as many of the great and the good from the world of Einstein’s relativity gathered at University College Cork to pay tribute to Professor Niall O’Murchadha, a theoretical physicist in UCC’s Department of Physics noted internationally for seminal contributions to general relativity.  Some measure of Niall’s influence can be seen from the number of well-known theorists at the conference, including major figures such as Bob WaldBill UnruhEdward Malec and Kip Thorne (the latter was recently awarded the Nobel Prize in Physics for his contribution to the detection of gravitational waves). The conference website can be found here and the programme is here.




University College Cork: probably the nicest college campus in Ireland

As expected, we were treated to a series of high-level talks on diverse topics, from black hole collapse to analysis of high-energy jets from active galactic nuclei, from the initial value problem in relativity to the search for dark matter (slides for my own talk can be found here). To pick one highlight, Kip Thorne’s reminiscences of the forty-year search for gravitational waves made for a fascinating presentation, from his description of early designs of the LIGO interferometer to the challenge of getting funding for early prototypes – not to mention his prescient prediction that the most likely chance of success was the detection of a signal from the merger of two black holes.

All in all, a very stimulating conference. Most entertaining of all were the speakers’ recollections of Niall’s working methods and his interaction with students and colleagues over the years. Like a great piano teacher of old, one great professor leaves a legacy of critical thinkers dispersed around their world, and their students in turn inspire the next generation!


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Snowbound academics are better academics

Like most people in Ireland, I am working at home today. We got quite a dump of snow in the last two days, and there is no question of going anywhere until the roads clear. Worse, our college closed quite abruptly and I was caught on the hop – there are a lot of things (flash drives, books and papers) sitting smugly in my office that I need for my usual research.


The college on Monday evening

That said, I must admit I’m finding it all quite refreshing. For the first time in years, I have time to read interesting things in my daily email; all those postings from academic listings that I never seem to get time to read normally. I’m enjoying it so much, I wonder how much stuff I miss the rest of the time.


The view from my window as I write this

This morning, I thoroughly enjoyed a paper by Nicholas Campion on the representation of astronomy and cosmology in the works of William Shakespeare. I’ve often wondered about this as Shakespeare lived long enough to know of Galileo’s ground-breaking astronomical observations. However, anyone expecting coded references to new ideas about the universe in Shakespeare’s sonnets and plays will be disappointed; apparently he mainly sticks to classical ideas, with a few vague references to the changing order.

I’m also reading about early attempts to measure the parallax of light from a comet, especially by the great Danish astronomer Tycho de Brahe. This paper comes courtesy of the History of Astronomy Discussion Group listings, a really useful resource for anyone interested in the history of astronomy.

While I’m reading all this, I’m also trying to keep abreast of a thoroughly modern debate taking place worldwide, concerning the veracity of an exciting new result in cosmology on the formation of the first stars. It seems a group studying the cosmic microwave background think they have found evidence of a signal representing the absorption of radiation from the first stars. This is exciting enough if correct, but the dramatic part is that the signal is much larger than expected, and one explanation is that this effect may be due to the presence of Dark Matter.

If true, the result would be a major step in our understanding of the formation of stars,  plus a major step in the demonstration of the existence of Dark Matter. However, it’s early days – there are many possible sources of a spurious signal and signals that are larger than expected have a poor history in modern physics! There is a nice article on this in The Guardian, and you can see some of the debate on Peter Coles’s blog In the Dark.  Right or wrong, it’s a good example of how scientific discovery works – if the team can show they have taken all possible spurious results into account, and if other groups find the same result, skepticism will soon be converted into excited acceptance.

All in all, a great day so far. My only concern is that this is the way academia should be – with our day-to-day commitments in teaching and research, it’s easy to forget there is a larger academic world out there.


Of course, the best part is the walk into the village when it finally stops chucking down. can’t believe my local pub is open!


Dunmore East in the snow today



Filed under History and philosophy of science, Teaching, Third level

Summer hols; summer school, swimming and that book

You must be finished for the summer? Like most academics, I get asked this question every day in summer, usually by village acquaintances convinced that college closes the day the students finish their exams.

Some lecturers in the Institutes of Technology do indeed take off from June 20th to September 1st; that is their right, given the heavy teaching load during termtime. However, for those of us who try to keep up the research, the summer months are the time to get something done, just like our colleagues in the universities.

For me, this is no chore  – the sheer bliss of being able to do quiet research without classes, meetings, staff interactions and all the rest of it. Very restful. Also, we’re having a serious heatwave in Ireland this month and I’m happy to escape to the cool, quiet office every day. So I plug away happily during the day and treat myself to a swim in my village in the evenings..


Tide’s in on Lawlor’s Strand in Dunmore East

Actually, I did give some ‘cameo’ lectures this week and last, to our summer school. We have a very nice bunch of engineering, computing and business students visiting from Kiel in Germany, and I had fun trying to condense my climate science course down to a one-hour presentation for each group. I haven’t given short presentations on climate before, it was very satisfying to prepare (see here for a copy of the talk)  The other thing I noticed was that students from the continent always seem to be very mature, polite and interested. I must look into an exchange sometime, do they have Erasmus for staff?

My main task this summer is to finish my little book on cosmology. It’s based on a course I have taught for some years and it’s been a lot of fun to write. Now I’m finding that it’s one thing to write a book and quite another to get it published! Still, I have plenty of time now to be writing book proposals and writing to publishers. In the meantime, I look forward to a swim in the sea everyday after work and a walk into the village. It’s funny to live in a village where others come for summer holidays!


Tide’s out on Lawlor’s Strand in Dunmore East


Unfortunately it’s so warm, we’re beginning to get quite a few jellyfish. Hope it cools down a little next week!


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A day in the life

There is a day-in-the life profile of me in today’s Irish Times, Ireland’s newspaper of record. I’m very pleased with it, I like the title  – Labs, lectures and luring young people into scence  – and the accompanying photo, it looks like I’m about to burst into song! This is a weekly series where an academic describes their working week, so I give a day-to-day description of the challenge of balancing teaching and research at my college Waterford Institute of Technology in Ireland.


Is this person singing?

There is quite  a lot of discussion in Ireland at the moment concerning the role of  institutes of technology vs that of universities. I quite like the two-tier system – the institutes function like polytechnics and tend to be smaller and offer more practical programmes than the universities. However, WIT is something of an anomaly – because it  is the only third level college in a largeish city and surrounding area, it has been functioning rather like a university for many years (i.e. has a very broad range of programmes, quite high entry points and is reasonably research-active). The college is currently being considered for technological university status, but many commentators oppose the idea of an upgrade – there are fears of a domino effect amongst the other 12 institutes, giving Ireland far too many universities.

It’s hard to know the best solution but I’m not complaining – I like the broad teaching portfolio of the IoTs, and there is a lot to be said for a college where you do research if you want to, not because you have to!


I had originally said that the institutes cater for a ‘slightly lower level of student’. Oops! This is simply not true in the case of WIT, given the entry points for many of the courses I teach, apologies Jamie and Susie. Again, I think the points are a reflection of the fact that WIT has been functioning rather like a university simply because of where it is.

Comments on the article are on the Irish Times page

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Resistors in series and parallel

In the last post, we saw that for many materials, the electric current I through a device is proportional to the voltage V applied to it, and inversely proportional its resistance, i.e. I = V/R (Ohm’s law). If there is more than one device (or resistor) in a circuit, the current through each also depends on how the resistors are connected, i.e., whether they are connected in series or in parallel.

In a series circuit (below), the resistors are connected one after the other (just as in a TV series, one watches one episode after another). The same current runs through each device since there is no alternative path or branch, i.e.  I = I1 = I2. From V = IR, we see the voltage across each device will be different; in fact, the largest voltage drop will be across the largest resistance (just as the largest energy drop occurs across the largest waterfall in a river). The total voltage in a series circuit is the sum of the individual voltages, i.e. V = V1+V2. As you might expect, the total resistance (or load) of the circuit is the simply the sum of the individual resistances, R = R1 + R2.


Series circuit: the current is the same in each lamp while there may be a different voltage drop across each (V = V1+V2 +V3)

On the other hand, resistors in a circuit can be connected in parallel (see below). In this case, each device is connected directly to the terminals of the voltage source and therefore experiences the same voltage (V = V1=V2). Since I = V/R , there will be a different current through each device (unless they happen to be of equal resistance) .The total current in a parallel circuit is the sum of the individual currents, i.e. I = I1+I2. A strange aspect of parallel circuits is that the total resistance of the circuit is lowered as you add in more devices (1/R = 1/r1 + 1/r2). The physical reason is that you are increasing the number of alternate paths the current can take.


Parallel circuit: the voltage is the same across each lamp but the currents may be different (I = I1+I2)

Confusing? The simple rule is that in a series circuit, the current is everywhere the same because there are no branches. On the other hand, devices connected in parallel see an identical voltage. In everyday circuits, electrical devices such as kettles, TVs and computers are connected in parallel to each other because it is safer if each device sees the same voltage source; it also turns out to be more efficient from the point of view of power consumption (an AC voltage is used, more on this later).

In the lab, circuits often contain some devices connected in series, others in parallel. In order to calculate the current through a given device, redraw the circuit with any resistors in parallel replaced with the equivalent resistance in series, and analyse the resulting series circuit.



Assuming a resistance of 100 Ohms for each of the resistors in the combination circuit above, calculate the total resistance of the circuit. If a DC voltage of 12 V is applied, calculate the current in the circuit. (Ans: 133 Ω, 0.09 A)


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Current, voltage and the French resistance

Last week, our 1st science students had their first laboratory session on electrical circuits. They haven’t met electricity in lectures yet, so I spent some time explaining the concepts of current and voltage.

In essence, current is the flow of electric charge around a circuit (measured in amps) while voltage is the energy that drives the current (and is measured in volts). I find it helpful to think of the two in terms of cause and effect; a current will only flow in the circuit if a voltage is applied. In simple circuits, this energy is supplied in the form of a DC battery (or voltage source) that drives the current through some device (or resistor) in the circuit.

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The lamp (or resistor) lights as the current goes through it, completing the circuit

You might expect that there is a simple relation between voltage and current, and sure enough, the German scientist Georg Ohm discovered that, for many materials, there is a linear relationship between the two. Ohm’s law states that the current I passing through a material connected to a voltage V is given by the simple equation I = V/R. Here, 1/R is the constant of proportionality and is called electrical resistance and you can see why from the equation: a material with a very large value of R will pass almost no current (bad conductor), while a material with very small R will yield a large current for the same voltage (good conductor). So the term has exactly the same meaning as it has in ordinary speech, e.g. the French resistance. Resistance is measured in volts per amp, also known as Ohms (Ω).


Many materials have a linear relation between voltage and current – the slope of the graph is the material’s resistance

In the experiment, the students apply a series of voltages to an unknown resistance in a circuit, and record the corresponding currents. A plot of voltage versus current then allows them to verify the linearity of the relation and the resistance is estimated from the slope of the line. (Strictly speaking, one should really put the voltage on the x-axis as it is the independent variable, but the calculation is simpler if the voltage is on the y-axis).

Measuring current and voltage

All of the above is fine in principle. Yet novices find the measurements quite difficult in practice. They have problems connecting the circuit because they get confused between measuring the current that flows through a device, and the voltage across it. It’s crucial to understand the difference between the two, and I suspect the modern multimeter adds to the confusion.


The ammeter reads the current running through the resistor while the voltmeter reads the voltage across it. A plot of voltage vs current gives a measurement of the resistance

When I was a student, the current was measured by passing the current through an ammeter (marked A in the diagram), an analog device with a nice big dial calibrated in amps or milliamps. The voltage across the resistor was measured by connecting a different instrument, the voltmeter, across the terminals of the resistor; this voltmeter was a separate meter with a dial calibrated in volts (marked V in the diagram). So an ammeter was always connected in series with the resistor/device, while the voltmeter was always connected across it (in parallel).

index   voltmeter

Current is measured by passing it through the ammeter (L) while voltage is measured by connecting across the voltmeter (R)

Nowadays, identical instruments are used for both; to measure current, one passes the current through the terminals marked ‘current’ of a multimeter, and the main dial on the meter is switched to the amp scale. To measure voltage, one connects the ends of the resistor across the terminals marked ‘voltage’ on an identical multimeter, and the dial is switched to volts. It sounds simple, but it’s easy to connect to the wrong terminals, getting no readings or blowing the fuse in the meter. More subtly, I think the clever circuity inside the multimeter hides the fact that current goes through while voltage drops across. All in all, I suspect students would understand circuits better if  we went back to separate instruments for measuring current and voltage….


The mysterious multimeter. To measure current, leads are connected to the sockets marked ‘common’ and ‘amps’; to measure voltage, one connects to the sockets marked ‘common’ and ‘voltage’.


1. If a 12-V voltage is applied across a resistor of 15, what current flows in the circuit? How many electrons per second does this current represent? (Ans: 0.8 mA,  5.0 x 1015 electrons)

2. What happens to the current if one end of the resistor accidentally touches the other? (Ans: the circuit resistance drops almost to zero and the current becomes very large – don’t try this in the lab!)

3. Ohm’s law is a misnomer – it is not a universal law of nature but simply a property of some materials (many materials have a nonlinear response to voltage, including your cat).

4. It might seem from Ohm’s law that a material with zero resistance can give infinite current! No such materials are known; the relation is simply not valid for these materials. However, some materials have extremely low resistance at very low temperatures, known as superconductors. A good application of superconductivity can be found at the Large Hadron Collider, where protons are guided around the ring by magnets made of superconducting material: this reduces power consumption enormously but the snag is that the entire accelerator has to be kept at extremely low temperatures during the experiments.


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