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Aaaarrrhh first year Marcus Wilson Jul 21

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It’s no secret that I don’t like teaching first year classes.  I find third year undergraduates far easier to teach. I think the main reason for this is that with the third years I don’t have such a large gap between my knowledge of the subject and theirs. That means that I don’t need to think so much about whether I am using words they are not familiar with, or whether my explanation draws on contexts and phenomena that the class hasn’t seen before. I know others take the opposite view – third year classes are harder because the material is more advanced – but to me that’s not a problem. What is a problem is communicating, and it is easier for me to do so with students who are closer to my ways of thinking.  Plus third years tend to speak a lot more and let you know when they don’t follow something, so it is less easy to lose a whole class without knowing it.

On Monday I did a first year tutorial in which I ended up in a horrible tangle  trying to explain something that to me is really simple. To be fair on myself, I think the question that I had to explain (which came from a website) was badly put together, but I should have done rather better than I did. First year teaching takes real practice (I think it does, anyway) . I’m very envious of people like Alison Campbell who excel in teaching large groups of first years.

As part of my PGCert in Tertiary Teaching, I experimented last semester with a method of finding out whether my class (a second year one in this case) is with me or not. (See for example Turpen and Finkelstein, Physical Review Special Topics, Physics Education Research 5, 020101 (2009) ) It’s a well-used method in physics teaching, though I gave it a bit of adeptation for my class. Essentially its formative assessment – ask the class multiple choice questions at the beginning of the lecture relating to last lecture’s material and have the class discuss it in pairs - not to test them for the sake of allocating marks, but for me to know where their understanding is at.  It worked well, I think – there were questions that the class struggled with that I thought they’d have grasped easily. That has got to be good overall for the students, because it allows me to go and unpick their reasoning and correct misconceptions. In a subject like physics, where so often one concept is built on another, the teacher (me) needs to know whether the students have that foundation or not – if not, there really is no point going on.

That’s another reason why I find third years easier to teach – by the time they reach third year, they have grasped those underlying concepts (if not, they’d be failing bigtime in second year). That means less preparation on my part is required. Maybe I’m just lazy.

Look after your graduates Marcus Wilson Jul 15

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I heard a snippet of Stephen Joyce on the radio this morning saying that the government may link funding of tertiary education to graduate employment – i.e. the amount of money given to The University of Waikato to support its teaching would be linked to the success of its graduates in securing employment. 

On the face of it, I think that’s perfectly reasonable. Of course, I have heard no details, and that is where the issues are likely to be. A government spends a huge fraction of its income on education, and it is utterly sensible (I would say with my tax-payer’s hat on ‘essential’ ) that it carefully considers what value it is getting from its expenditure. But I can think of a few issues here.

What would be meant by graduate employment? Would the proverbial job at McDonalds count as graduate employment? Does the job have to be closely aligned with the actual degree course undertaken? If so, how close? Who defines that? University and polytechnic courses can teach skills that aren’t tied to the actual academic material – our science graduates should be able to do things like write a coherent written report and give presentations – and those skills are useful in a great range of jobs, not just sciency ones.

All that remains to be defined. But one positive spin-off I can see for the universities is that it will force them to keep good track of their graduates. My two old universities (Cambridge and Bristol) send me frequent magazines and emails (in the case of Cambridge) letting me know what’s happening – and one reason is that happy graduates that still feel part of their former university have a habit of giving them money. And some graduates  will go on to earn rather large salaries (I wish), and become a useful source of income for their institution.  In fact, Cambridge is exceptionally skilled at asking for donations – I get at least one phone call a year from someone pursuing this point (in a very nice way) – even now that I am in New Zealand (though just once the caller didn’t register the time-zone difference … he didn’t get a happy graduate on the end of the phone at midnight).

More money from graduates means there is less reliance on government income, which means there is less for us lecturers  to fret about when ministers hint at changes to the funding system. I wait to see what will happen

Peak Oil, peak platinum, peak physics Marcus Wilson Jul 14

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I guess most of us now are familiar with the concept of Peak Oil. At some point (maybe about now) oil production will peak, then it will be in decline as reserves run out. The only way around this issue is to reduce our use of it, which means, for example, reconsider our transport options.

At cafe scientitique last week, Shaun Hendy drew our attention to some other resources that are looking decidedly finite. The specific ones he drew on are platinum and palladium, which are used for high-tech applications. Since demand for high-tech equipment is growing rather faster than our demand for oil, one might speculate we could be hitting peak platinum before peak oil, and perhaps even that peak platinum might hit our civilized western mobile-phone-and-ipod-and-general-gadget-loving cities harder than peak oil. The price of platinum  certainly has gone up sharply in the last few years, and nearly all of it comes from a single source in South Africa (imagine the politics if nearly all our oil came from a single source…) We may have to become more clever in recycling high-tech equipment.

Another ‘peak’ example, though of a slightly different form, I read about in this month’s Physics World magazine. The world is running short of Helium 3.  (That’s the isotope of helium that has two protons and one neutron in its nucleus.) Helium 3 has previously been in abundant supply as a by-product of nuclear weapons development – tritium (an isotope of hydrogen), which is produced in nuclear-weapons reactors, decays into Helium 3.

Why is this an issue? Well, helium 3 has some seriously odd properties when it gets cold (e.g. see Wikipedia) which means that amongst other things it can be used to cool systems to very low temperatures (much less than 1 Kelvin). And low temperatures are important for investigating basic physics, such as quantum effects – for example there is minimum thermal noise to mask what is going on. Some condensed matter physicists are getting a little worried that not enough is being produced. Recently, supplies have been sidetracked into screening the US borders for smuggling of nuclear material (ironically, the very stuff that produced the helium 3 in the first place; helium 3 captures neutrons very easily so can be used as the basis of a detector). 

The most pessimistic condensed matter physicists might even go as far to say that we have reached ‘peak physics’, unless we are able to get a decent supply of Helium 3 back to the physics labs. It’s not an issue I’d thought about until reading the article.  I suspect there may be several other materials that also fall into this ‘peak’ category; you might be able to think of a few.

 

Hands on science Marcus Wilson Jul 09

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Yesterday we had a one-day symposium here at the University on ‘Science in the Public’ – we brought together nearly 30 people from across the country (OK – across the North Island to be precise), all of who were involved in science communication in some manner.  It was a fascinating day as we learned about what others were doing and ways we could make our own efforts better.

We ended the day with a tour of Exscite at Waikato museum  (Hands-on science exhibits) and a cafe scientifique, in which Shaun Hendy talked about nanotechnology.

There is heaps that I could blog about, but for now, I’ll just pick up on one theme. We had a great talk by Peter Hodder, looking amongst other things at some of the history of science exhibitions in New Zealand.  They are not a new thing – 100 years or so ago there were some big events, partly because the scientists setting them up and performing (e.g. public chemistry experiments to wow the audience) needed the income that the public brought in.  I was impressed by the lengths that some exhibits went to – e.g. a recreation in Christchurch of Te Whakarewarewa thermal area in Rotorua – including ‘working’ geysers – albeit supplied through a pump and cold water.

Then in the 1920s, when the government began to realize that science was worth investing in, scientists seemed to lose the desire (they now had proper salaries) and perhaps the ability to communicate with the public through such impressive exhibits. Scientists seemed to become men-in-white-coats working away from the public gaze on something way too technical for the ordinary person to understand.

More recently, in the last 20 years or so, the hands-on exhibits have made a comeback. But, especially in NZ, it’s been in a rather ad-hoc manner. I was rather taken by the graph that Peter showed comparing the amount of funding given to the main centres in NZ to establish interactive science exhibits in their museums with the population in that centre.  Absolutely no relation at all – some places (e.g. Dunedin I think) got well supplied, others (e.g. Hamilton) got a whole lot less. (N.B.. I might be wrong with those place names, I’m going from memory here… I looked particularly at Dunedin, since its a museum I’ve visited a lot, and Hamilton, since it’s where I live and work.)

Another issue in NZ is that each museum has to rely on repeat visitors to be financially viable, so that means refreshing its exhibits at a high rate. That’s costly. There is some relience on touring exhbitions to bring in the money, but, by the time they hit the small centres (e.g. Hamilton) they can be looking a bit worse for wear and sometimes out of date.  That can be contrasted with, say, the Science Museum in London which has (or had, on my last visit a couple of years ago) some very tired looking things that have been there a long time – but, if you are in a city of 10 million people with a never-ending supply of tourists, then that’s not really a problem.

Interactive, hands-on stuff doesn’t have to be confined to museums though.  We also heard about a great project, LENScience, in which school children can get interactive (if not ‘hands on’ !) with real scientists - both ‘live’ (in the same room) or via video-link and live text link and so forth.  That’s another blog entry though.

A new element! Marcus Wilson Jul 03

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One of my PhD students this week brought to my attention a new element. Well, a new element to me anyway. Samarium (Sm) which featured in a paper she’d been reading (in the context of magnetism), nestles neatly between promethium and europium in the lanthanides of the periodic table (I know, because I’ve just gone and looked it up). Little wonder it had escaped my attention all these years.

I’m taking a few days’ holiday next week before the students arrive back so probably no blog posts for a week I’m afraid.

Group intelligence Marcus Wilson Jun 30

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Last night I half-watched the programme on TVOne about swarms. (I say half-watched because I was mostly listening to it while doing the washing up). It is certainly fascinating how large groups of fairly simply behaving creatures can have a ‘group intelligence.’ This kind of organization of small units into a larger entity is well studied in physics. Ants are particularly fascinating – an individual ant doesn’t possess a great deal of intellectual capacity, but a whole colony seems to have some extra intelligence of its own.  At one point the programme compared an individual ant to a brain cell, and the whole colony to a brain. Like single ants, brain cells on their own aren’t particularly complicated systems – you can describe them with just a few equations (I know – I do that in some of my research). Basically if you poke them with enough current they ‘fire’, and if two cells that touch through a synapse fire at commensurate times, they can either strengthen or weaken that synapse between them. They can also ‘leak’ a bit of current from one cell to a neighbour. All very simple really. But stick lots together and you have a brain. (It could be your brain).

But here’s where we get a problem with the analogy – we humans are conscious (for 16 hours a day, give or take)  - I know I am as I write this, and I assume you are as you read it. But can a colony of ants be conscious?  I find it hard to believe.  What would that mean for the ethics of putting down poison to kill off the colony that’s taken up residence in your house? Are you killing a being with a high-level of consciousness?   Here’s the problem for neuroscientists – what is it about the collection of cells in your brain that results in consciousness? Basically no-one has a clue. There are some ideas discussed, but getting any scientific evidence is going to be tricky. We can certainly say things like how consciousness correlates to the pattern of firing activity, for example the voltages  picked up on the electroencephalogram (electrodes stuck on the scalp), and anaesthetists will often use the electroencephalogram to give them clues as to whether a patient is actually unconscious, but what is it about these firing events that leads to consciousness? Or what is it about consciousness that leads to those firing events? Or what is the unknown process that influences both the firing of cells and consciousness? I don’t know.

What I’m saying here, is that consciousness isn’t necessarily just a by-product of throwing lots of interacting brain cells together and so we should be a bit careful about saying a colony of interacting ants is ‘intelligent’, if that means we get the picture that there is some conscious thinking related to the colony. 

The Blue Brain project, based at Lausanne in Switzerland, is (in simple terms) an attempt to simulate an entire region of a rat brain on a computer. The idea is that the computer simulation will respond in the same way as the rat brain. But will the computer simulation be conscious? I wouldn’t think so.

As another example, think of plants. My colleague Alison Campbell has described some ‘intelligent’ (and quite surprising) plant behaviour. Plants that hunt, plants that communicate with others. Sounds like the triffids are already here.

Patience in experimenting Marcus Wilson Jun 28

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I’ve spend most of today in our new teaching lab, grappling with a piece of experimental equipment. Over the break between our A and B semesters (i.e. now) we’re moving our 2nd and 3rd year undergraduate physics lab out of one room and into another. It’s a small part of a large plan to use the available space to full advantage, and it means lots of things are moving about at the moment. A bit like moving house, with our deadline being two Monday’s time, when semester starts, and everything has to be up and running.

For the most part, we can move a piece of equipment from one room to another, set it up, and have it work without too much difficulty. But there are three or so pieces of equipment that are a location-sensitive. The one I’ve been working with today is a NMR / MRI machine.  It’s just a baby – not the size you find in hospitals – but it is an excellent teaching tool – one of the best bits of kit I think our third years get to play with.

Rather than have a huge coil to generate a magnetic field (what you need for nuclear magnetic resonance), as happens in the hospital, this machine uses the earth’s magnetic field. Convenient, yes, but a bit awkward too, because the field in the lab isn’t exactly nice and uniform. Walk around the room with a compass, and you’ll see the needle drift several degrees – there is, after all, a whole lot of steel in the building, and that is going to influence the magnetic fields in its vicinity.  Now, to use the NMR in the lab, I need to know what size of the magnetic field (because strength of the field controls the resonant frequency). Although the old lab and the new lab are close by, the strength of the earth’s field in the two of them proved surprisingly different, and it took me a while to get any signal on the machine at all.

Setting the machine up in its new location is rather like tuning a radio with a poor quality aerial when you don’t know the frequency of the radio station you want, nor do you quite know the direction of the transmitter, in a room with a lot of electrical noise. It takes a lot of patience, looking at different frequencies, until you pick up a little signal in amongst the noise. (This, being a physics lab, is just loaded with electrical noise – that’s another problem).  It’s an example of how, with noisy data, you can still get a ’signal’, but you need to average over lots and lots of trials to see it. It’s just basic statistics really; the more averages you take (in my case, the more times I sample the data), the easier it is to see a signal buried in the noise, because the noise slowly ‘averages out’ to zero, while the signal doesn’t. But with a weak signal, it takes some time. 

With a lot of patience, I got there – found my NMR signal. Then I could slowly tune up the apparatus to work with that signal, and finally at the end of the afternoon I have it working tolerably well.  But basically it took a day to do it. 

In research, we often need far longer than a day to tune-up our equipment, and a good experimenter will have lots and lots and lots of patience. ( I do not claim for one moment to be one of these – as an undergraduate I chose my papers very carefully to keep practical work to an absolute minimum – and then went on to do a PhD which just involved pen-and-paper and a computer – ironic that I now teach our experimental physics papers). Patience is certainly a virtue for a physicist. 

 

 

The essence of physics Marcus Wilson Jun 24

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Exams are looming, and I’ve had a constant stream of students coming to me this week asking me questions.

One question I’ve had has been asked by two students independently, relating to an example calculation done in a text book. The question goes like this: "I’ve been going through this example, and I get the answer 0.159, but the book says its 160. I don’t get it"

To be honest, I’m a bit saddened that students weren’t able to figure this one out for themselves. Experience tells me that when I am a factor of 1000 out, it’s almost always because of an issue with the units – somewhere a ‘milli-something’ or a "kilo-something" has been overlooked. It is what comes from extracting numbers from a question and putting them into the calculator without thinking about what numbers are being used.  And, indeed, if the students had looked at the units the textbook answer was given in, they would have spotted that the book’s 160 mA m-1 is exactly the same as the 0.159 A m-1 the student has. (Here also we have a significant figures issue).

The students’ question says it all.."I get the answer 0.159".  But 0.159 what?  

Units and dimensions are fundamentally key to physics. There’s probably no other area where they are so critical. One could even say that units is what physics is all about. Describing physical quantities. Units are so important that there is a whole area of branch of physics devoted to establishing them in practical terms - metrology – and international committees dedicated to doing such boring (but essential) things as deciding on what one ampere actually means. Without this, physics will fall apart. This is one reason why lecturers like me bleat on about paying attention to the units.

Claims on the electromagnetic spectrum Marcus Wilson Jun 23

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I wrote a couple of weeks ago about the value of electromagnetic spectrum real-estate. It proved quite topical – as I wrote it I had no idea that Stephen Joyce was about to release an emphatic "no" to requests from the Maori Council for rights to the 4G spectrum (See e.g. the TVNZ coverage of this story).

What’s this about?  Well, when NZ television viewers (which I guess is most of us) are finally forced to throw away their otherwise perfectly good analogue sets in a few years time, and go digital, the frequencies currently used to broadcast the analogue signals (the ‘4G’ band) become available for other uses. They’re earmarked for mobile phone and internet, and will be of significant value to the people who have the rights to use them.

So who controls organizations’ rights to use this spectrum (i.e. transmit things)? The government says it is them, and solely them. And I would imagine that’s the way it is in almost all countries with effective governments. A free-for-all of the airwaves doesn’t work; you can’t have two broadcasts on the same frequency in the same region or your receiver will pick up a combination of both, which isn’t likely to be very meaningful.

Apparantly the spectrum has been declared as taonga by the Waitangi Tribunal (implying that there should be some Maori ownership / control of it), but previous governments have refused to recognise this. (N.B. For you non-New Zealanders, taonga, broadly speaking, can be translated as ‘treasure’). In the TVNZ article Joyce is quoted as saying  "Because spectrum was not in use at the time that the treaty was signed [1840] and was not known at the time that the treaty was signed, it’s difficult to argue it was taonga". 

That’s reasonable enough, but one could also argue that just because people didn’t know of the existence of something doesn’t mean it didn’t exist.  If a new oil-field were discovered on Maori-owned land somewhere, one could expect a very reasonable claim to be made by the owners on the contents.  In 1840, no-one knew that this entity (’the spectrum’) existed (Hmm.. could debate that one, I mean people knew that the visible spectrum wasn’t all there was and that infra-red existed), let alone the potential value of it, but it was still there. Maybe not as a treasure (can you treasure something you don’t know exists?) but certainly as something of value.

One could counter that by saying that the government is duty bound to act in the best interests of its citizens (ha ha, yeah, right)  including Maori, and, in this case, proper development of the 4G band should ensure massive benefit to the country. Since NZ is on the edge of nowhere, a good internet etc is likely to be more useful to NZ than it is to many other countries. And I would like to think that the government is in the best position to deliver on that.

The more I think about it the more thorny this one is.

 

Why conventional astronomy is rubbish Marcus Wilson Jun 21

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My father-in-law sent me this link at the weekend. It’s to a book published in 1914 (that’s nineteen fourteen, not sixteen fourteen, or nine fourteen), describing how children of the day are being taught lies with regard to the shape and movement of the earth in the solar system.

Does the Earth Rotate? No.  By William Edgell.

http://web.archive.org/web/20080122142029/http://www.litotes.demon.co.uk/dTeR/doesTheEarthRotate.html

It is quite, quite hilarious. It illustrates how, once a person has got an idea in their head (in this case that the Earth is flat and motionless), they will hold to it tenaciously and will distort and misinterpret data that would tell them otherwise, if only they were prepared to look at it at face value.

Edgell makes some wonderfully fanciful interpretations of phenomena that would otherwise tell him that the earth is curved. The fact that ships disappear over the horizon, hull first, is pretty strong evidence of earth curvature. Edgell dismisses this effect as due to sea mist that is thickest closest to the sea surface and therefore obscures the hull first. Funny how he makes no mention of the fact that this phenomenon is most clearly seen on a very clear day, when there is no mist.

New Zealand gets mentioned a lot, presumably because it is at the opposite side of the globe (if you hold to that wrong interpretation) to England. Edgell notes that this fallacious understanding would imply that kiwis are upside down, and asks the reader to think whether this is reasonable.

But the most interesting thing I can see is Edgell’s comment that in New Zealand the pole star subtends an angle of 40 degrees to the horizon. Now, I have lived in NZ for six years or so, and I can say that I have never, ever, ever seen the pole star from here. For good reason. And I don’t expect ever to do so. I can only think that he has misinterpreted a comment from an astronomer about the pole star in New Zealand being 40 degrees below the horizon. (Which is why I’m never likely to see it here.) He has clearly never travelled to New Zealand, or the equator, or, from the sounds of things, very far at all, or he might have noticed just how the stars change.

But, hey, that doesn’t stop you being an expert in world geography, does it?

I wonder if Mr Edgell ever changed his mind later on?

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