I couldn’t resist a short post to mark the success of England’s cricketers down under in successfully retaining The Ashes. After getting themselves comprehensively thrashed in the Third Test of the Ashes series in Perth, to tie the level the series 1-1 (with one match drawn), the pressure was on when the Fourth Test started on Boxing Day in Melbourne. However, it all seemed to get to the Australians more than the English: Australia were dismissed for a paltry 98 after being put into bat by England captain Andrew Strauss who won the toss. England finished the day on 157 without loss, with defeat for Australia already probable at stumps on the opening day. England batted all the second day and a bit of the third, amassing 513 all out, and then had Australia 169 for 6 at the end of Day Three. Although the last few Australian batsmen showed a bit of spirit on Day Four, they were eventually all out for 258, leaving England the victors by an innings and 157 runs, their second innings victory of the series.
Now they are 2-1 up in the series with one Test to play (at Sydney), which means they can’t lose the series and therefore keep the Ashes, which they won in England last year (2009). I hope England keep their focus and go on to win at Sydney too. I’d like to see them win the series outright. Incidentally, if I’ve done my sums right, Australia have now won 123 Ashes tests since the first in 1882, to England’s 99, so if England can win in Sydney it will be their 100th.
My Australian friends and colleagues will be wincing at this outcome, but although England have proved worthy winners this time I’m sure Australia will be back to winning ways before too long. As an English cricket fan, I’ve endured enough disappointments to make this victory especially sweet. I dare say when the Australians do reclaim the Ashes at some point in the future their supporters will feel the same. As it is in life, so it is in cricket – the good times make the bad times worth enduring.
I thought I’d mark this very special occasion with a poem called Brahma by Andrew Lang. It’s a clever parody of a poem by Ralph Waldo Emerson, and the reference to Hinduism seems to fit with the theme of a cyclic universe of sporting success and failure.
If the wild bowler thinks he bowls,
Or if the batsman thinks he’s bowled,
They know not, poor misguided souls,
They too shall perish unconsoled.
I am the batsman and the bat,
I am the bowler and the ball,
The umpire, the pavilion cat,
The roller, pitch, and stumps, and all.
At the end of day two of the Second Ashes Test between England and Australia, England were 317 for 2 in response to Australia’s 245 all out. Cook is 136 not out and Petersen 85 not out. Going well for England down under in the heat of Adelaide, I’d say. Australian captain Ricky Ponting seems to be hoping for help from above..
..although, given that this is in Australia, surely his hands are actually pointing downwards?
Just a quick post to commemorate the record-breaking First Test of the Ashes series between England and Australia in Brisbane that finished yesterday. It was notable for a number of reasons, including Australian bowler Peter Siddle’s hat-trick in England’s first innings, and some fine batting by Mike Hussey and Brad Haddin in Australia’s first innings, but chiefly for an extraordinary fightback by England’s batsmen in their 2nd innings which took them to an amazing 517 for 1 declared from a situation in which they might well have folded. Well played Messrs Strauss, Cook and Trott for all getting centuries and saving the game.
The way the press have been going on about the result you’d think England had won, but it was only a draw. There’s a long way to go – another four Tests to be precise – before the fate of the Ashes is decided. Still, England have already done better than they did last time they played an Ashes series in Australia. They lost that one 5-0!
I thought I’d post this little poem by Simon Rae to mark the occasion. There wasn’t that much evidence of high-quality spin bowling in the First Test, but A Red Ball Spins is more about the fact that although it might be winter here and the domestic season long over, somewhere in the world there’s always cricket, lovely cricket…
A red ball spins, a swallow’s flight, That every generation follows From rituals first performed in meadows To epic Tests in packed arenas.
Shadows signal the close of play Then slip through turnstiles into light: Another match, another day. Around the world the red balls spins.
Up early this morning, cold notwithstanding, to take part in an all-day workshop on Public Attitudes to Science conducted by the market-research organization IPSOS-Mori on behalf of the Department for Business Innovation and Skills (BIS) I can’t really say much about what happened since it’s an ongoing research project, but it was very interesting and particularly nice to talk to the participants (who were aged 18-24). My role was as a “science expert” so my job was to explain a bit about how the kind of science I do actually works in practice, compared with what they thought before the event.
On the way home I had to find my way back through the crowded streets of Cardiff. Today was the last day of the autumn rugby internationals, and Wales were playing New Zealand at home. There was a fantastic atmosphere in the city, as always on match days, although the combination of a rather boisterous rugby crowd with large numbers of Christmas shoppers did slow down my journey home. The game just ended, Wales 25 New Zealand 37; not as one-sided as many feared and a much better spectacle than last week’s awful match against Fiji.
I took a few pictures of Bute Park on my way to the event this morning. It looked very beautiful, but it wasn’t half cold early on. I doubt if there’ll be much rugby played on the sports fields for a while, because the ground is frozen solid at the moment!
The summer draws ever nearer to its close and autumn beckons.
The latest marker of the turning season to rush past was the last match of cricket’s County Championship, which ended yesterday. It was a disappointing finale for my local team, Glamorgan, who had a chance of winning promotion to Division 1 having spent most of the season in second place in Division 2. However, after a feeble first innings batting performance against Derbyshire – and a lot of rain here in Cardiff – they could only draw their final game. Meanwhile, third-placed Worcestershire responded to a generous declaration by first-placed Sussex by scoring 306-6 in only 55 overs to win with time to spare. Thus, Sussex and Worcestershire (who got relegated last year) get promoted back to Division 1, while Kent and Essex (who were promoted last year) get relegated. Better luck next year for Glamorgan. Nottinghamshire, by the way, won the Championship.
In the end it was quite an exciting final day of the county season but since it’s now all over until next spring it seems appropriate to mark the end of the County Championship with one of the classic cricket poems, Close of Play, by Thomas Moult.
How shall we live, now that the summer’s ended,
And bat and ball (too soon!) are put aside,
And all our cricket deeds and dreams have blended —
The hit for six, the champion bowled for none,
The match we planned to win and never won? …
Only in Green-winged memory they abide.
How shall we live, who love our loveliest game
With such bright ardour that when stumps are drawn
We talk into the twilight, always the same
Old talk with laughter round off each tale —
Laughter of friends across a pint of ale
In the blue shade of the pavilion.
For the last time a batsman is out, the day
Like the drained glass and the dear sundown field
is empty; what instead of Summer’s play
Can occupy these darkling months ere spring
Hails willows once again the crowned king?
How shall we live so life may not be chilled?
Well, what’s a crimson hearth for, and the lamp
Of winter nights, and these plump yellow books
That cherish Wisden’s soul and bear his stamp —
And bat and ball (too soon!) are put aside,
Time’s ever changing, unalterable score-board,
Thick-clustered with a thousand names adored:
Half the game’s magic in their very looks!
And when we’ve learnt those almanacs by heart,
And shared with Nyren … Cardus ….the distant thrill
That cannot fade since they have had their part,
We’ll trudge wet streets through fog and mire
And praise our heroes by the club-room fire:
O do not doubt the game will hold us still!
Just a quick post to share a picture taken at last night’s Twenty20 International in Cardiff between England and Pakistan. We had the entire spectrum of Welsh weather to contend with, but the worst of yesterday’s rain was over well before the match started and the SWALEC stadium, just ten minutes’ walk from my house, was a fine sight under a variety of peculiar cloud formations and the floodlights, as you can tell from the picture I took on my phone.
Pakistan won the toss and batted first, but didn’t make a very good fist of it and were bowled out for a mere 89 from their 20 overs. England had a little wobble during the run chase but in the end won comfortably by 6 wickets.
Unfortunately, the crowd numbered only a few thousand so the atmosphere was a bit flat and Pakistan’s poor showing with the bat made it all a bit of anti-climax, but it was still a good way to precede a nice curry. I’ve heard various theories as to why the attendance was so poor, but I think it’s pretty obvious: at £45 for a game whose format ensures it can last no longer than about three hours, tickets for this match were just too expensive. I think the authorities should think again about their pricing strategy.
I don’t know why, but last week was my most popular week ever, at least in terms of blog hits! I was going to follow up with a foray into the role of spin in quantum mechanics, but decided instead to settle for a less ambitious project for this evening.
Yesterday I walked past the cricket ground at the SWALEC Stadium in Sophia Gardens, Cardiff, during the Twenty20 international between England and Pakistan. There is another match of this type tomorrow night which I’ll actually be going to, as long as it’s not rained off, but I have too many things to do to go to both games. Anyway, England’s excellent off-spinner Graham Swann was bowling when I watched through a gap in the stands at the river end of the stadium. He seemed to be getting an impressive amount of turn, and I got wondering about how fast a bowler like “Swannee” actual spins the ball.
For those of you not so familiar with cricket here’s a clip of another prodigious spinner of the ball, Australia’s legend of legspin Shane Warne:
For beginners, the game of cricket is a bit similar to baseball (insofar as it’s a game involving a bat and a ball), but the “strike zone” in cricket is a physical object ( a “wicket” made of wooden stumps with bails balanced on the top) unlike the baseball equivalent, which exists only in the mind of the umpire. The batsman must prevent the ball hitting the wicket and also try to score runs if he can. In contrast to baseball, however, he doesn’t have to score; he can elect to play a purely defensive shot or even not play any short at all if he judges the ball is going to miss, which is what happened to the hapless batsman in the clip.
You will see that Warne imparts considerable spin on the ball, which has the effect of making it change direction when it bounces. The fact that the ball hits the playing surface before the batsman has a chance to play it introduces extra variables that you don’t see in baseball, such as the state of the pitch (which generally deteriorates over the five days of a Test match, especially in the “rough” where bowlers have been running in). A spin bowler who causes the ball to deviate from right to left is called a legspin bowler, while one who makes it turn the other way is an offspin bowler. An orthodox legspinner generates most of the spin from a flick of the wrist while an offspinner mainly lets his fingers do the torquing.
Another difference that’s worth mentioning with respect to baseball is that the ball is bowled, i.e. the bowler’s arm is not supposed to bend during the delivery (although apparently that doesn’t apply if he’s from Sri Lanka). However, the bowler is allowed to take a run up, which will be quite short for a spin bowler, but long like a javelin thrower if it’s a fast bowler. Fast bowlers – who can bowl up to 95 mph (150 km/h) – don’t spin the ball to any degree but have other tricks up their sleeve I haven’t got time to go into here. A typical spin bowler delivers the ball at speeds ranging from 45 mph to 60 mph (70 km/hour to 100 km/hour).
The physical properties of a cricket ball are specified in the Laws of Cricket. It must be between 22.4 and 22.9 cm in circumference, i.e. 3.57 to 3.64 cm in radius and must weigh between 155.9g and 163g. It’s round, made of cork, and surrounded by a leather case with a stitched seam.
So now, after all that, I can give a back-of-the-envelope answer to the question I was wondering about on the way home. Looking at the video clip my initial impression was that the ball is deflected by an angle as large as a radian, but in fact the foreshortening effect of the camera is quite deceptive. In fact the ball deviates by less than a metre between pitching and hitting the stumps. There is a gap of about 1 metre between the popping crease (where the batsman stands) and the stumps – it looks much less from the camera angle shown – and the ball probably pitches at least 2 metres in front of the crease. I would guess therefore that it actually deflects by an angle less than twenty degrees or so.
What happens physically is that some of the rotational kinetic energy of the ball is converted into translational kinetic energy associated with a component of the velocity at right angles to the original direction of travel. In order for the deflection to be so large, the available rotational kinetic energy must be non-negligible compared to the original kinetic energy of the ball. Suppose the mass of the ball is , the translational kinetic energy is where is the speed of the ball. If the angular velocity of rotation is then the rotational kinetic energy , where is the moment of inertia of the ball.
Approximating the ball as a uniform sphere of mass and radius , the moment of inertia is . Putting , cancelling on both sides and ignoring the factor of – because I’m lazy – we see that the rotational and translational kinetic energies are comparable if
or , which makes sense because is just the speed of a point on the equator of the ball owing to the ball’s rotational motion. This equation therefore says that the speed of sideways motion of a point on the ball’s surface must be roughly comparable to speed of the ball’s forward motion. Taking km/h gives m/s and m gives radians per second, which is about 100 revolutions per second. This would cause a huge deviation (about 45 degrees), but the real effect is rather smaller as I discussed above (see comments below). If the deflection is actually around 15 degrees then the rotation speed needed would be around 30 rev/s.
This estimate is obviously very rough because it ignores the direction of spin and the efficiency with the ball grips on the pitch – friction is obviously involved in the change of direction – but it gives a reasonable ballpark (or at least cricketground) estimate.
Of course if the bowler does the same thing every time it’s relatively easy for the batsman to allow for the spin. The best bowlers therefore vary the amount and angle of spin they impart on each ball. Most, in fact, have at least two qualitatively different types of ball but they disguise the differences in the act of delivery. Offspinners typically have an “arm ball” which doesn’t really spin but holds its line without appearing to be any different to their spinning delivery. Legspinners usually have a variety of alternative balls, including a topspinner and/or a flipper and/or a googly. The latter is a ball that comes out of the back of the hand and actually spins the opposite way to a legspinner while being produced with apparently the same action. It’s very hard to bowl a googly accurately, but it’s a deadly thing when done right.
Another thing also worth mentioning is that the rotation of the cricket ball also causes a deviation of its flightpath through the air, by virtue of the Magnus effect. This causes the ball to curve in the air in the opposite direction to which it is going to deviate on bouncing, i.e. it would drift into a right-handed batsman before breaking away from him off the pitch. You can see a considerable amount of such movement in the video clip, away from the left-hander in the air and then back into him off the pitch. Nature clearly likes to make things tough for batsmen!
With a number of secret weapons in his armoury the spin bowler can be a formidable opponent, a fact that has apparently been known to poets, philosophers and astronomers for the best part of a thousand years:
The Ball no Question makes of Ayes and Noes,
But Right or Left, as strikes the Player goes;
And he that toss’d Thee down into the Field,
He knows about it all — He knows — HE knows!
Strange day. After a few days dominated by departmental duties I actually started to get down to doing some research, or at least trying to remember where I was with half-a-dozen projects I haven’t looked at for a while. Hopefully I’ll get some of them finished in the next few weeks now that the students have gone for the summer, but inevitably my concentration’s disrupted a bit by the World Cup. It’s so tempting just to have a quick peek at the scores…
It was the turn of the department’s contingent of Italians to slope off to watch their World Cup match this afternoon. Strangely, though, they didn’t come back afterwards. Perhaps it was something to do with their team – the current holders of the World Cup – losing 3-2 to Slovakia and now being out of the competition.
After a somewhat disappointing start, the tournament is producing some smashing games – although perhaps not if you’re Italian! Tonight I watched a splendid performance from Japan, who beat Denmark 3-1 in great style. Many of my most recent research collaborations have involved scientists from Denmark, Italy and Japan. I know which group will be happier tonight!
More importantly, after an initial dearth it’s good to see a recent increase in the number of clichés being deployed by the comentators, especially in the final third and at the end of the day, defending deep and holding a high line. Tonight’s match even produced a mention of the Last Chance Saloon, which is one I haven’t heard for a while.
Coming home around 7pm I walked in the bright evening sunshine past the cricket ground at Sophia Gardens which is where England were playing Australia in a 50-over one-day international. In fact when I walked to work this morning, spectators were already arriving. That surprised me because the game didn’t start until 2.30pm. Quite a few Australians among them too.
I had toyed with the idea of going myself but never got round to buying a ticket. I’m not as keen on one-day cricket compared to Test matches so decided to give it a miss. As I meandered home through Bute Park, I did stop to watch a bit of the England innings from the Taff embankment from which I saw Monty hold off the Australians for a hard-earned draw at the end of last summer’s test match. The curious thing was that although the sun was shining, all the floodlights were on. I suppose that’s to get the players used to the lights in good time before they’re actually needed.
The other noticeable sign of a big cricket match was an extraordinary blend of food smells wafting up from the assorted purveyors of greasy comestibles surrounding the stadium. I can’t say the smell was particularly enticing, although it didn’t put me off my dinner.
I’ve waited to post this until the match finished, which it has now done. I could hear the roar from my garden as England won by four wickets with 5 overs to spare. No doubt the England supporters will be heading for the local pubs for a few drinks before closing time. Come to think of it….
My agenda for today was dominated by three events, each involving a different form of progression. The timing was a coincidence, I think.
First, this morning, a bunch of interviews with our first-year postgraduate research students. Like most universities, the first year of a PhD at Cardiff University is a probationary period so we get the students to write a report on what they’ve been doing and also get input from their supervisor. This is then followed up by a panel interview, with 3-4 members of staff, at which a judgement is made as to whether to allow them continue. This used to be a relatively informal thing involving supervisor and one other member of staff, but I’ve recently taken over as Director of Postgraduate Studies in the School of Physics & Astronomy and made the process a bit more rigorous, having the same panel talk to all the students. It all passed off pretty well apart from the fact that a couple of students are away and I’ll have to put them through the process later on in the summer when they get back from their observing trips and whatnot.
After a spot of form-filling and a quick lunch we went straight into another examiners’ meeting, this time for undergraduate students. We already went through the marks for graduating students a couple of weeks ago, but today we had to look at the results for our Prelim candidates, and Years 1 and 2. Here the focus for most staff is on their personal tutees, usually 4 in each year, checking they all progress as intended to the following year and presenting any special circumstances. This meeting can be quite fraught, but this year went smoothly.
Which brought us to the last issue of progression, and the one I was less optimistic about prior to the event. However, England did manage to win their game against Slovenia in the FIFA World Cup by the not entirely convincing scoreline of 1-0. That means they too progress to the next round, although how much further than that they can go is not very clear. Well done to the USA too, who beat Algeria to win the group and take their place in the last 16.
All in all, a busy but productive and satisfying day. Now I’m going to watch one more game of football and have a glass or two of wine before having an early night.
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, the translational kinetic energy is 
where 
is the speed of the ball. If the 
then the rotational kinetic energy 
, where 
is the 
, the moment of inertia is 
. Putting 
, cancelling 
– because I’m lazy – we see that the rotational and translational kinetic energies are comparable if
, which makes sense because 
is just the speed of a point on the equator of the ball owing to the ball’s rotational motion. This equation therefore says that the speed of sideways motion of a point on the ball’s surface must be roughly comparable to speed of the ball’s forward motion. Taking 
km/h gives 
m/s and 
m gives 
radians per second, which is about 100 revolutions per second. This would cause a huge deviation (about 45 degrees), but the real effect is rather smaller as I discussed above (see comments below). If the deflection is actually around 15 degrees then the rotation speed needed would be around 30 rev/s.
In the Dark 