Archive for September, 2015

PigGate Latest

Posted in Politics with tags , , on September 21, 2015 by telescoper

Unless someone has been telling porkies, it seems our Prime Minister committed a sexual act with dead pig.

I have been looking for updates on the BBC website but there’s not a sausage. There is however plenty of coverage on Sty News.

Although David Cameron apparently didn’t go the whole hog, I wonder if he has ever committed a rasher act? I think he might even be for the chop. Can anything save his bacon now? He needs to draw a loin under this very quickly.

Anyway, it’s a crackling story. On the other hand the whole thing might just be a poke in a pig pig in a poke..

Meanwhile, Conservative Party Central Office has issued new guidelines to all Tory MPs..

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Only in English

Posted in Uncategorized on September 20, 2015 by telescoper

Taking a break from work this weekend today I’ve been reading the latest edition of The Oldie magazine, and doing the crossword therein.

I noticed a reader’s letter about the importance of correct positioning of the word “only” in an English sentence, illustrated with the following example:

“The bishop gave the bun to the baboon”.

The point is that you can put the word “only” anywhere in this sentence (at the beginning, at the end, or between any two consecutive words) and the result each time is grammatically correct, but each choice yields a different meaning..

It’s a funny language, English!

A Botanic Garden of Planets

Posted in Poetry, The Universe and Stuff on September 19, 2015 by telescoper

I’ve been reading, with rapidly growing delight and astonishment, an amazing poem called The Botanic Garden , which was written by Erasmus Darwin in 1789. It is a truly wonderful work which depicts the Universe as a vast laboratory set up by a Divine Creator through verses that generate a thrilling sense of  momentum and vitality. Take this example, a passage from the First Canto, dealing with the creation of the stars and planets:

‘Let there be Light!’, proclaimed the Almighty Lord,
Astonish’d Chaos heard the potent word: – 
Through all his realms the kindly Ether runs,
And the mass starts into a million suns; 
Earths round each sun with quick explosions burst,
And second planets issue from the first; 
Bend, as they journey with projectile force, 
In bright ellipses bend their reluctant course; 
Orbs wheel in orbs, round centres centres roll, 
And form, self-balanced, one revolving Whole.

It doesn’t quite fit with modern theories of star and planet formation, but it’s certainly beautifully expressed!

How to Solve Physics Problems

Posted in Cute Problems, Education with tags , , , , , , on September 18, 2015 by telescoper

It’s Friday afternoon at the end of Induction Week here at the University of Sussex. By way of preparation for lectures proper – which start next Monday – I gave a lecture today to all the new students in Physics during which I gave some tips about how to tackle physics problems, not only in terms of how to solve them but also how to present the answer in an appropriate way.

Richard-Feynman-cornellI began with Richard Feynman’s formula (the geezer in the above picture) for solving physics problems:

  1. Write down the problem.
  2. Think very hard.
  3. Write down the answer.

That may seem either arrogant or facetious, or just a bit of a joke, but that’s really just the middle bit. Feynman’s advice on points 1 and 3 is absolutely spot on and worth repeating many times to an audience of physics students.

I’m a throwback to an older style of school education when the approach to solving unseen mathematical or scientific problems was emphasized much more than it is now. Nowadays much more detailed instructions are given in School examinations than in my day, often to the extent that students  are only required to fill in blanks in a solution that has already been mapped out.

I find that many, particularly first-year, students struggle when confronted with a problem with nothing but a blank sheet of paper to write the solution on. The biggest problem we face in physics education, in my view, is not the lack of mathematical skill or background scientific knowledge needed to perform calculations, but a lack of experience of how to set the problem up in the first place and a consequent uncertainty about, or even fear of, how to start. I call this “blank paper syndrome”.

In this context, Feynman’s advice is the key to the first step of solving a problem. When I give tips to students I usually make the first step a bit more general, however. It’s important to read the question too. The key point is to write down the information given in the question and then try to think how it might be connected to the answer. To start with, define appropriate symbols and draw relevant diagrams. Also write down what you’re expected to prove or calculate and what physics might relate that to the information given.

The middle step is more difficult and often relies on flair or the ability to engage in lateral thinking, which some people do more easily than others, but that does not mean it can’t be nurtured.  The key part is to look at what you wrote down in the first step, and then apply your little grey cells to teasing out – with the aid of your physics knowledge – things that can lead you to the answer, perhaps via some intermediate quantities not given directly in the question. This is the part where some students get stuck and what one often finds is an impenetrable jumble of mathematical symbols  swirling around randomly on the page. The process of problem solving is not always linear. Sometimes it helps to work back a little from the answer you are expected to prove before you can return to the beginning and find a way forward.

Everyone gets stuck sometimes, but you can do yourself a big favour by at least putting some words in amongst the algebra to explain what it is you were attempting to do. That way, even if you get it wrong, you can be given some credit for having an idea of what direction you were thinking of travelling.

The last of Feynman’s steps  is also important. I lost count of the coursework attempts I marked this week in which the student got almost to the end, but didn’t finish with a clear statement of the answer to the question posed and just left a formula dangling.  Perhaps it’s because the students might have forgotten what they started out trying to do, but it seems very curious to me to get so far into a solution without making absolutely sure you score the points.  IHaving done all the hard work, you should learn to savour the finale in which you write “Therefore the answer is…” or “This proves the required result”. Scripts that don’t do this are like detective stories missing the last few pages in which the name of the murderer is finally revealed.

So, putting all these together, here are the three tips I gave to my undergraduate students this morning.

  1. Read the question! Some students give solutions to problems other than that which is posed. Make sure you read the question carefully. A good habit to get into is first to translate everything given in the question into mathematical form and define any variables you need right at the outset. Also drawing a diagram helps a lot in visualizing the situation, especially helping to elucidate any relevant symmetries.
  2. Remember to explain your reasoning when doing a mathematical solution. Sometimes it is very difficult to understand what students are trying to do from the maths alone, which makes it difficult to give partial credit if they are trying to the right thing but just make, e.g., a sign error.
  3.  Finish your solution appropriately by stating the answer clearly (and, where relevant, in correct units). Do not let your solution fizzle out – make sure the marker knows you have reached the end and that you have done what was requested. In other words, finish with a flourish!

There are other tips I might add – such as checking answers by doing the numerical parts at least twice on your calculator and thinking about whether the order-of-magnitude of the answer is physically reasonable – but these are minor compared to the overall strategy.

And another thing is not to be discouraged if you find physics problems difficult. Never give up without a fight. It’s only by trying difficult things that you can improve your ability by learning from your mistakes. It’s not the job of a physics lecturer to make physics seem easy but to encourage you to believe that you can do things that are difficult.

To illustrate the advice I’ve given I used this problem, which I leave as an exercise to the reader. It is a slightly amended version the first physics problem I was set as tutorial work when I began my undergraduate studies way back in 1982. I think it illustrates very well the points I have made above, and it doesn’t require any complicated mathematics – not even calculus! See how you get on…

problem

Quantum Madness

Posted in The Universe and Stuff with tags , , on September 18, 2015 by telescoper

A very busy day lies in store so I only have time for a quick morning visit to the blog. If you enjoyed the recent guest post on the “hidden variables” interpretation of Quantum Mechanics, then you will probably enjoy reading a paper that recently appeared on the arXiv with the abstract:

Motivated by some recent news, a journalist asks a group of physicists: “What’s the meaning of the violation of Bell’s inequality?” One physicist answers: “It means that non-locality is an established fact”. Another says: “There is no non-locality; the message is that measurement outcomes are irreducibly random”. A third one says: “It cannot be answered simply on purely physical grounds, the answer requires an act of metaphysical judgement”. Puzzled by the answers, the journalist keeps asking questions about quantum theory: “What is teleported in quantum teleportation?” “How does a quantum computer really work?” Shockingly, for each of these questions, the journalist obtains a variety of answers which, in many cases, are mutually exclusive. At the end of the day, the journalist asks: “How do you plan to make progress if, after 90 years of quantum theory, you still don’t know what it means? How can you possibly identify the physical principles of quantum theory or expand quantum theory into gravity if you don’t agree on what quantum theory is about?” Here we argue that it is becoming urgent to solve this too long lasting problem. For that, we point out that the interpretations of quantum theory are, essentially, of two types and that these two types are so radically different that there must be experiments that, when analyzed outside the framework of quantum theory, lead to different empirically testable predictions. Arguably, even if these experiments do not end the discussion, they will add new elements to the list of strange properties that some interpretations must have, therefore they will indirectly support those interpretations that do not need to have all these strange properties.

You can download a PDF of the full paper here. It’s a short piece, but with a very good list of references for further reading.

Science is (even more) Vital (than ever)

Posted in Politics, Science Politics with tags , on September 17, 2015 by telescoper

It’s almost five years since I participated in a rally in London to protest against proposed cuts to the UK science budget. Since then research funding has been heavily squeezed by a “flat cash” settlement that threatens the survival our science base, with consequent damaging effects on the long-term future of the economy. This graphic, from a post by Stephen Curry, says it all:

science is still vital

Back in 2010, most of us were relieved that the outcome of the Chancellor’s spending review was a level funding in cash terms, although the decline in real terms funding since then has been enormously challenging across the board. The forthcoming spending review puts us in an even more dangerous situation. After the 2010 election the Coalition government announced a “ring fence” that protected science spending from cash cuts for the duration of the last Parliament (although this has, as the graphic above demonstrates) translated into real-terms cuts year on year. This time any commitment to a ring-fence from the Conservative government has been conspicuous by its absence. Indeed, its decision to claw back funding of STEM subjects through HEFCE has demonstrated its intention to remove even this modest protection. The government has signalled its desire to cut overall spending massively this time, and there are few places left for the axe to fall other than in research. Now the UK’s research councils are being told to budget for cuts of 20% and 40% to their core funding. This will lead to the abandonment of many international research projects and lead to large-scale redundancies across the sector, driving the best of our scientists abroad. These plans are bad not only for science, but for the economy as a whole because it is only through growth triggered by research and innovation that this country can hope to recover from the mess that it is currently in.

As scientists and as people who care about this country’s future we can not allow these cuts to go ahead. I will be attending an event at the Conway Hall in London organised by Science is Vital to campaign against these reckless plans. I encourage you to do likewise. I don’t know if the government will listen, but we have to try.

Maria Callas: “Ah, rendetemi la speme…”

Posted in Opera with tags , on September 16, 2015 by telescoper

I’m reminded that Maria Callas (“La Divina”) passed away on this day in 1977, so by way of a tribute here she is singing a famous “Mad Scene” from the Opera I saw at the Wales Millennium Centre last week, I Puritani by Vincenzo Bellini. This is a rare recording of the young Callas, aged only 25, made in 1949. It’s historically important too, because Callas stepped into this production at short notice in Venice that year, having started out on a  career as a dramatic soprano singing Wagnerian roles. Critics sneered when they heard that she had been cast as Elvira, but almost overnight she transformed the role and so began her almost single-handed revival of the entire bel canto repertoire.

One critic wrote:

Even the most sceptical had to acknowledge the miracle that Maria Callas accomplished… the flexibility of her limpid, beautifully poised voice, and her splendid high notes. Her interpretation also has a humanity, warmth and expressiveness that one would search for in vain in the fragile, pellucid coldness of other Elviras.

Her she is as Elvira, deranged by the loss of her beloved who has vanished without explanation. It’s as beautiful as it is heartbreaking. It’s not the best sound quality, but the emotional power of her voice shines through. Few singers have even come close to matching Callas in roles like this.

Qui la voce sua soave mi chiamava…e poi sparì.
Qui giurava esser fedele,  qui il giurava,
E poi crudele, mi fuggì!
Ah, mai più qui assorti insieme nella gioia dei sospir.
Ah, rendetemi la speme,  o lasciate, lasciatemi morir.

September in the Rain

Posted in Jazz with tags , , on September 16, 2015 by telescoper

Need cheering up on a rainy September afternoon? The gorgeous voice of Sarah Vaughan should do the trick!

Seven Years In The Dark

Posted in Biographical with tags on September 15, 2015 by telescoper

7th Birthday Badge Superhero

When I logged onto WordPress to write today’s post I received a message that it was the 7th anniversary of my registration with them as a blogger and thus took my first step into the blogosphere; that was way back on 15th September 2008. I actually wrote my first post that day too. Unfortunately I didn’t really know what I was doing on my first day at blogging – no change there, then –  and I didn’t actually manage to figure out how to publish this earth-shattering piece. It was only after I’d written my second post that I realized that the first one wasn’t actually live, so the two appear in the wrong order in my archive.

I’d like to take this opportunity to send my best wishes, and to thank, everyone who reads this blog, however occasionally. According to the WordPress stats, I’ve got readers from all round the world, including one in the Vatican! If you’re interested in statistics then, as of 13.30 today, I have published 2,934 blog posts, and have received 2,460,789 hits altogether; I get an average of about 1300 per day, but this varies in a very erratic fashion. The greatest number of hits I have received in a day is 8,864 (at the peak of the BICEP2 controversy). There have been 22,482 comments published on here and 1,391,901  rejected as spam or abuse; a lot goes on behind the scenes here that you really don’t want to know about!

Anyway, the numbers don’t really matter but it does mean a lot to know that there are people who find my ramblings interesting enough to look at, and sometimes even to come back for more!

 

 

 

Battle of Britain Day

Posted in Film, History with tags , , , on September 15, 2015 by telescoper

Today is the 75th Anniversary of the day that historians regard as the climax of the Battle of Britain. To commemorate this, a huge flypast will take place across the South of England. Unfortunately, the weather isn’t too great today, and I don’t think it will be quite the spectacle that was intended, although Purple, Brown and Black sections are due to fly over Brighton from RAF Goodwood and perhaps the clouds will have broken up by the time they get here. Normally Battle of Britain Day is commemorated on a Sunday, as 15th September 1940 lay on a Sunday.

I had a friend – now long dead – who served as a fighter pilot in the RAF during the Battle of Britain and I once asked him about the tactics they used. He explained that they didn’t really have any tactics. When scrambled they were usually lucky if they managed to get to the right altitude before the enemy were on them. And if they did, they just flew head on at the incoming planes and tried to shoot them down. There was little point in attacking a big formation from behind with a handful of planes, which was the usual situation: you might pick off one or two but the bombers would carry on to their target. You had to attack from the front in order to scatter them. He added that on a good day, if you were feeling exceptionally brave, you might even keep your eyes open as you screamed straight into the enemy at getting on for 400 mph.

Another event of 15th September 1940 exemplifies the almost insane courage of the RAF pilots. A formation of Dornier bombers penetrated the British air defencesa as central London, where it was engaged by planes from a number of RAF squadrons, including the Hurricane of Flight Sergeant Ray Holmes. Holmes got into position to shoot down one Dornier, but when attempted to fire he discovered he had run out of ammunition. In an act of amazing bravery he decided to ram the Dornier. He succeeded ins slicing off the plane’s tail and it came down on Victoria Station. Somewhat improbably, Holmes managed to bale out and, though injured, survived to fight again. He died in 2005.

The other thing that this event reminded me of was the film Battle of Britain. The movie is a bit dated now, largely because some of the special effects don’t really stand up to modern comparisons: no cgi when it was made, for example. The best thing about it for me, though, is the wonderful music written for the film by William Walton, especially in the following sequence where the dogfights are shown with only the music as soundtrack. This turns the shots of terrifying close-range combat into a something a lot more than an action movie. It’s a work of art.

The context of this sequence is, as far as I know, historically accurate. Over the summer of 1940 the Luftwaffe had sent raid after raid over to attack Britain, these raids increasing in size as time went on. Hugh Dowding, Head of Fighter Command at that time, refused to let his planes be drawn into a huge battle against numerically superior forces and instead kept most of his planes in reserve, sending up only a squadron or half a squadron to meet the incoming planes. Thanks to the breaking of the German Air Force Enigma code, Dowding knew that the Luftwaffe pilots had been handing in grossly exaggerated reports of how many planes they had been shooting down. Convinced that the RAF was on the brink of collapse, the Germans launched an enormous air raid on September 15th 1940 intended to deliver the knockout blow and prepare the way for invasion.

Dowding knew that they were coming, and put every available plane at the RAFs disposal into the air. The survival of this country was at stake during this battle. There were no reserves. When the Luftwaffe arrived over Britain their pilots were aghast to find the air filled with Spitfires and Hurricanes whose pilots, having been consistently outnumbered in the battles so far, relished the chance to fight for once with something close to numerical equality with the enemy. The RAF scored a decisive victory, convincing Hitler to abandon his plans for an invasion in 1940.