Sunday, January 8, 2012

The Universe is not quite so Super

The past year has been an important one for Physics. Over the last few months the LHC has steadily gathered data and, just before the year's close, there was the announcement that it may have found evidence of the elusive Higgs boson. This announcement dominated science headlines for several days, even though the evidence was far from conclusive. Interestingly, however, there has been little, if any, mention of the things the LHC has not discovered. This may seem a rather odd point because, surely, discovering something ought to be far more important than not discovering something? So why do I feel otherwise?

Over the past forty years many of the major theories developed in particle physics, including SuperString theory, have been based on a hypothesis known as SuperSymmetry. SuperSymmetry is, mathematically speaking, a beautiful theory which, if true, could tie together many concepts concerning particles, forces and the nature of space and time. There is, however, no evidence that the theory is correct. The theory does, though, make a number of testable predictions, some of which should have come to light in results from the LHC. Naturally, the fact that no evidence has emerged has concerned some - so much so that many are now tweaking the theory in order to make it fit the evidence - or rather, lack of evidence.

I would love there to be evidence of SuperSymmetry but, under the circumstances, am inclined to say that, all things considered equal, the simplest theory is most likely to be the correct one, and the simplest theory on this case, given the lack of evidence, is that SuperSymmetry is wrong.

So perhaps it is time to abandon this theory and look elsewhere for an answer to questions of particle physics? However, many Physicists have too much tied up on this to give up so easily: After all, if the theory of SuerSymmetry is wrong, then so must any theory that incorporates it, including SuperStrings. Imagine if you had devoted your entire career to researching a theory just to see it evaporate before your eyes - wouldn't you do what you could to save it?

Personally I believe that many Physicists have committed the folly of believing that they could discover an ultimate theory of everything and have venture too far along untrodden paths. There has, to my mind, been no significant advancements in theoretical particle physics in the last forty years. Perhaps we should go back to the basics again and look at incrementally improving our models once more rather than lunging blindly towards some final theory? Whatever happens, there is still a huge gulf in our understanding that needs filling - one which may well exist for many generations to come.

Sunday, December 11, 2011

Leaving jokes aside

I have a theory:
You can tell a lot about a person by the sort of jokes they laugh at.

At one level this may seem fairly obvious, but I'm not talking here about labelling people who laugh at dirty jokes as perverts and those who laugh at racist ones as fascists. My theory is that jokes can reveal a huge amount about the way someone thinks on a deep level.

Take my favourite joke, for example. Before I tell it I ought to explain that most people who hear it don't find it remotely funny. A select few, however, find it hilarious and giggle everytime they think about it for days upon end.

What do you call a fly without wings?
A walk.

Did you laugh? Maybe you did; maybe you didn't. The joke is, for me at least, a very visual one and I believe that it is mainly people with a strong visual mind who tend to find it most funny. Certainly when I told the joke recently
to my top A level set (which consists of some cry visual learners) a high proportion of them laughed, and a couple almost collapsed. The same
Joke told to a group of non-physicists, however, produced a much more muted reaction. Coincidence? Or could there be something to my theory? Do visual jokes appeal most to visual thinkers? Do Jokes that play upon words appeal more to auditory thinker?

On a final note, when someone first said "Sarcasm is the lowest form of wit" were they being sarcastic?

Thursday, November 3, 2011

Seeing the light

Galileo was one of the first people to attempt to measure the speed of light. He failed.

Looking back with hindsight it is easy to regard his attempt as a little naive: It consisted of people stood on hill tops, flashing lanterns at each other and measuring how long it took for the flashes of light to travel around the circuit formed by these people. Clearly the reaction times of each of these individuals was a big factor in the reliability of the results and consequently Galileo was left to conclude that the time taken by the light was swamped by the uncertainties due to reaction times.

But was Galileo naive for even trying it? Many people certainly think so. But suppose we replaced the lanterns with air horns and, instead of measuring the speed of light, used a similar method to measure the speed of sound? Would that be naive? To most people the speed of sound is also pretty fast - afterall, when talking to each other we don't notice a time lapse between lips moving and hearing sounds - the speed of sound, to all intents and purposes, appears to be infinite! And yet, the Galilean method is capable of yielding pretty good results.

I like discussing Galileo's experiment with my students for several reasons, but mainly so that they can appreciate the differences between uncertainties and systematic errors and how data can be analysed in the light of such factors. Human reaction time actually has both a systematic component and an uncertainty: T systematic error (of about 0.2 seconds) is due to the physical time it takes for someone to react, whilst the random uncertainty is due to the fact that sometimes people reaction slightly faster and at other times they react slightly slower. The uncertainty can be estimated quite easily by repeating the experiment many times and looking at the spread of results. By repeating an experiment many times and taking an average the affect of the random uncertainty can also be reduced, just leaving the systematic error.

Suppose you were now to carry out the experiment using a different set of hills, so as to vary the distance that the light pulses travel. By doing so you could soon plot a graph of distance against time. The y-intercept of this line would give you the systematic error, whilst the gradient should yield your speed.

Clearly, when carried out for light, the gradient of the resulting line would be very great and have a huge uncertainty, but carried out using sound it should yield a reasonable estimate whilst teaching some very important scientific principles.

Why don't you try it out? I'm certainly planning to do so.

Wednesday, October 26, 2011

Changing the game

Eighteen months ago my device of choice was the iPad. It was a running joke amongst some of my colleagues that mine never left my side. I was scornful of smart phones for the simple reason that, whilst they were great for doing things such as receiving email, they were hopeless when it came to sending it - a fault that the larger keyboard of the iPad helps to overcome. Consequently I took my iPad everywhere: It enabled me to reply to messages within minutes of receiving them; the calendar helped me keep track of meeting and appointments; it enabled me to carry (nearly) all of my textbooks around with me, along with various useful apps; it also gave me a means of sharing and editing documents on the go. I had started to find it indispensable.

The thing that has changed this, at least in part, is the iPhone 4s. Apple have referred to Siri as being a "Game changer" and I am inclined to agree - but not in the way most people think. In my opinion the "Personal Assistant" part of it is largely a gimmick - the really useful part is the voice recognition that is built into all apps using the standard keyboard. Of course voice recognition is nothing new - not even on smart phones - but it is the close integration here that makes the difference. On laptops voice recognition has gone out of favour in recent years largely due to the fact that, even at 98% accuracy, the time taken to correct mistakes makes it inconvenient compared to a traditional keyboard. But on a smart phone, with the inherent limitations of any keyboard small enough to fit on such a device, voice recognition suddenly makes document creation a reality (well, in a quiet environment it does). Sure, there are still mistakes that require correction (proof reading is essential if you are to avoid some of the embarrassing errors I've almost made!) but the time taken to correct them is small compared to how long it would take to type out the message on the phone's keyboard.

All of which brings me to an important point: ICT is currently changing extremely fast - both in terms of what we use it for and the way in which we use it to do the things we want. So why do ICT lessons in most school still focus on software packages which could very well be obsolete by the time our current pupils leave school? In my experience traditional ICT lessons are very uninspiring - the pupils who want to know already know and the ones that don't couldn't really care. Wouldn't it be better to use ICT lessons to discuss matters such as how ICT is shaping the world, its likely future and the dangers associated with ICT in a social context? Pupils can pick up all the other skills, such as spreadsheets and word processing, as and when they need them, such as when they need to start analysing data and plotting graphs in science, or to write up a laboratory report.

By the way, this Blog was dictated using Siri. (And only four mistakes - unless you happen to spot some I missed!)

Thursday, October 20, 2011

The death of experiments?

When I set up my website,, it was not intended to replace experimentation in the classroom but merely to present a means of sharing good practise with colleagues in other schools. Shortly after posting my first videos, however, I stumbled across something potentially very interesting: When, on an occasion, an experiment failed to work as I had intended I turned to one of my video clips. To my surprise my pupils seemed more engaged in the video then they had been in the original experiment, even though the video was one of me performing the very same experiment in the very classroom we were in.

Now I have absolutely no intention of ever abandoning experiments, nor do I suggest that other people do the same, but this experience does suggest something very revealing: In this media obsessed age do pupils respond better to videos of experiments than to experiments performed live before they're very eyes? Perhaps it's worth giving this a little thought.

Saturday, October 8, 2011

Better the devil you don't

During the past couple of years I have observed teachers delivering a variety of lessons. Surprisingly, perhaps, most of these lessons have been in subjects very different to Physics.

The idea of a non-specialist teacher observing a lesson and, furthermore, providing feedback may seem a little strange if not, even, of little benefit. My experiences, however, over the past couple of years have transformed my own opinion of this.

Let's face it, it doesn't take an expert to recognise an outstanding teacher - or, for that matter, a failing one. But can a non-specialist actually provide meaningful feedback in a subject very different to their own? Well I would argue that not only can they do so, but they might be able to offer better quality feedback than a colleague from the same department. The problem with colleagues is that they often come along with their own preconceptions about how certain topics should be taught and their own expertise in a subject can, sometimes, also blind them to the problems that the pupils may face during lessons. A non-specialist, on the other hand, may be better able to empathise with the experience of pupils and, coming without the preconceptions of the experts, may be able to make novel suggestions that wouldn't occur to other teachers.

This approach has worked very well for me over the past few years - so much so that nowadays I readily welcome non-physicists into my own lessons and, furthermore, often find their advice and feedback more helpful than that of my closest colleagues.

Saturday, October 1, 2011

Why I like being lazy

About a year ago one of my colleagues told me I was working too hard. I thanked him for what I thought was a compliment upon my ability to get things done. However, he went on to explain that by doing too much for other people they were actually doing less themselves and that in doing less they were actually learning less.

The notion that by doing less you can get pupils to do more is one that is explained in Jim Smith's "The Lazy Teacher's Handbook" - it's well worth a read. All too often experienced teachers make the mistake of saying too much and providing too much guidance to pupils. Why not try doing to opposite: Shut up and back off - it has become a favourite piece of guidance that I now pass on to others. You might be surprised by how much your pupils achieve.