Tuesday, 18 December 2012

Molecule vs Molecule – Brian Clegg

In a number of recent posts I’ve looked at the ways that nanotechnology coatings like those produced by P2i can be used to make everything from mobile phones to trainers water repellent – and at the natural examples of this same phenomenon – but I haven’t really considered the science behind this technology – which is all about the electromagnetic interaction of molecules.
We’re probably most familiar with this kind of interaction in an attractive way. As I write this, there is a heavy frost outside. Water is turning from liquid to solid. Yet were it not for a particular molecular interaction, this would be an impossibility because water would boil below -70 °C. There would be no liquid or solid water on the Earth and, in all probability, no life.
The interaction that makes life possible is hydrogen bonding. This is an electromagnetic attraction between a hydrogen atom in one molecule, and an atom like oxygen, nitrogen or fluorine in a second molecule. When hydrogen is bonded to one of these atoms there is a relative positive charge on the hydrogen and a relative negative charge on the oxygen (say). This happens because the hydrogen atom’s only electron is in its bond, leaving a positively charged ‘end’ to the molecule, while the oxygen atom has four outer electrons not in its bonds, which are repelled away from the electrons in the bonds, giving it a negative charge.
Put two molecules alongside each other and the positively charged hydrogen is attracted to the negatively charged oxygen in its neighbour. The two molecules are drawn towards each other. There’s a force pulling the molecules together, and that means if you want to break them apart – say to boil liquid water – then it takes more energy that it otherwise would, as you have to overcome that force. Result: a much higher boiling point.
This inter-molecular attraction also accounts for another oddity that means aquatic creatures can survive in icy cold weather. Solid water – ice – is less dense than the liquid form, so it floats, leaving the water beneath still liquid. It’s sometimes said this is a unique property of water. It’s not – acetic acid and silicon, for instance, are both denser as a liquid than a solid – but it is unusual. It happens because the six-sided shape of a water crystal won’t fit with the way the hydrogen bonds pull the hydrogen of one water molecule towards the oxygen of another. To slot into the structure, these bonds have to stretch and twist, pulling water molecules further apart than they are in water’s most dense liquid form.
Hydrogen bonding would not be a good mechanism to consider if you wanted to keep liquids off an object. It would tend, rather, to keep them in place. So to produce a water resistant coating, you are looking instead for molecules that won’t attract. I have a personal interest in this. My father was an industrial chemist and was part of the team that developed one of the world’s first fabric conditioners. He used to bring home experimental jars of turquoise gloop from work to try out at home. And the principle behind a fabric conditioner or fabric softener is the opposite of cosy hydrogen bonds.
Such conditioners work by making clothes dirty with a special kind of dirt. Conditioners leave a thin residue on the fabric fibres. These molecules have several roles, but the significant one here is that they tend to repel each other, making the detailed structure of the fibres fluff up and giving the fabric a softer, more luxurious feel, lubricating the fibres when they move against each other.
This is very much fabric conditioner on fabric conditioner interaction. But to achieve a water-repellent coating we need to combine aspects of the two effects to get an interaction between the molecules in the coating and the water molecules that we are trying to get away from a product as quickly as possible.
P2i’s nanocoating is a polymer with molecules that are long-chains which can be either hydrocarbons or poly fluorinated . These start out as individual monomers – the molecules that will eventually be bound together in a polymer – which are exposed to a low power radio signal at 13.56 MHz to produce a plasma, a gas-like collection of ionised monomers, which then polymerize directly on the object being coated. It’s not a case of applying a polymer like sticking on an outer coating, but rather of creating it in place on all surfaces of the object to be protected.
Water forming into droplets on a tissue with a P2i coating
The molecular action here is rather more subtle than in a fabric conditioner. The coated surface has a low surface energy – significantly lower than that of water. Surface energy is a way of describing how much ability the surface of a substance has to produce interactions. P2i’s coating is unusually reluctant to interact, giving it a very low surface energy, around 1/3 that of the non-stick substance PTFE (Teflon). This means that the water is much more attracted to itself, through hydrogen bonding, than it is to the surface of the material. The result is that rather than wetting the surface – spreading out as a thin layer – the water forms spherical drops, because most of the attraction the water molecules feel is towards other water molecules and with all this inward attraction the natural result in the formation of a sphere.
As the water is in self-contained droplets on the surface, it will roll off in these beads without interacting with the material. This is why you can have the kind of remarkable result shown in the Richard Hammond TV show where he pulled a ringing phone out of a toilet and it still worked. The water was not given a chance to wet the surface and short out or corrode the electronics.
We tend to think of a substance in terms of its macro properties – those that we can see and feel. But we can only properly understand what’s going on by taking a close up look. When it comes to how stuff works, it’s a molecule versus molecule world.
Images courtesy of P2i

Thursday, 13 December 2012

Thinking Statistically – Uri Bram ****

This is a delightful little book (just three chapters) introducing three of the fundamental aspects of statistics that can get us confused: selection bias, edogeneity (effectively missing external factors which are influencing the outcome) and the use of Bayesian statistics, an approach that is very powerful but makes it easy to go astray.
I wouldn’t quite describe this as a popular science book – there are probably rather too many equations – but it is excellent both as providing a bit of understanding for those making use of statistical methods (it’s all too easy to just crank the handle without understanding what you are doing and thereby come up with the wrong results) and as  an introduction for the general reader who isn’t put off by a little bit of jargon and equations in what is, nonetheless, a very readable little book.
Thinking Statistically is short enough to read in a couple of hours, and I think it’s a credit to the author that I thought ‘Oh, really, I wanted more!’ when I got to the end. Uri Bram’s aim is to get the reader taking a more statistical viewpoint. Not necessarily wheeling out the statistical big guns every time you make a decision, but at least being aware of the statistical processes you are undergoing mentally, often unconsciously.
If you would like to know a bit more about statistics, but find the whole business a bit baffling, this is a good place to start.
You may wonder what the cover has to do with statistics. So did I. The simple answer is nothing.
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Review by Brian Clegg

Wednesday, 12 December 2012

The Science of Middle Earth – Henry Gee ****

When I saw this book (subtitled “Explaining The Science Behind The Greatest Fantasy Epic Ever Told!” in the original US edition), I thought it was time to put my foot down. Okay, Douglas Adams’ delirious fantasy, The Hitchhiker’s Guide to the Galaxy was largely a science fiction parody, so Science of Hitchhiker’s made sense. Even Science of Discworld works, thanks to the conceit of treating it as the view of fantasy characters of Discworld observing our science. But Science of Middle Earth? Isn’t it all swords and sorcery? What’s more, Tolkien was famously a romantic who longed for a non-existent bucolic rural past, typified by the hobbits’ Shire (while conveniently forgetting the rampant disease, infant mortality and frequent malnutrition, that were just some of the joys of the real rural past). Didn’t Tolkien attack the whole idea of science and technology as the black vision of the likes of his number II baddy, Saruman?
Henry Gee, a senior editor of the definitive science journal Nature in his day job, makes a striking case for taking a different viewpoint. He reminds us firstly that Tolkien’s own speciality, the study of words and language, a subject that is at the heart of The Lord of the Rings and his other heavy duty fiction, is a science. He also makes it clear that Tolkien wasn’t anti-science per se (apparently Isaac Asimov was a favourite of his). What he was against was the wrong attitude to science – letting it control us, rather than the other way around. In fact, Gee argues persuasively that, for instance, the Elves in LoTR don’t use magic (they say this themselves), but technology that is so in tune with nature that it’s hard to distinguish from it.
All in all this makes for a fascinating and very unusual entry in the “Science of…” league. Firstly it’s a very literary and precise book for such a subject. There’s as much about language as there is about “normal” science, and Gee’s approach has a scholarly care that may seem a little dry to the followers of more straight forward popular science, but that works surprisingly well. After the aspects of language, a lot of space is given to the biology of Middle Earth – where did orcs come from? What is the biology of ents? – all fascinating stuff.
There is one iffy bit of science. Gee suggests that the palantiri, the long distance seeing stones that feature in the book, could be linked by quantum entanglement, allowing instant communication. The trouble is, while quantum entanglement does provide an instant link across any distance, it can only provide the result of a random outcome – it can’t instantly communicate any information [1]. (It’s just as well: if it could, it would be possible to send a message through time and disrupt causality.) It’s fine to come up with real world scientific solutions to oddities of fiction, but they ought to make sense with science as we know it.
Just occasionally, for instance when Gee was struggling to explain how the One Ring could make people invisible I wanted to shout “What’s the point? It’s just a story!” But that’s not the main reaction to this book. Any Tolkien fan will find fascinating insights into the man and a side of his interests that is wildly underrepresented in what has been written about him. And as an exercise in “Science of…” attached to a work of fiction it’s one of the best around [2].
[1] In the ebook edition this problem is highlighted and explored, but only in a note at the back of the book, which still leaves the error in the main text.
[2] The Science of Middle Earth is even better in the ebook edition [3] (would Tolkien have approved?), which has been updated from the original, though most of the updates seem to be in the end notes. So, for instance, where in the main text Gee refers to the difficulties of juggling various e-devices that don’t communicate (like PDAs – remember PDAs?), he updates this in the notes.
[3] If possible, go for the ebook edition.
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Review by Brian Clegg

Saturday, 8 December 2012

Meaning in Mathematics – John Polkinghorne (Ed.) ***

In this book a number of leading mathematicians, philosophers and physicists, each contributing a chapter, offer us a range of reflections on the philosophy of mathematics, looking at, for example, the extent to which mathematics can be considered objective, and the issue of discovery versus creation in mathematics.
I really liked the format of the book. Each chapter is followed by a brief commentary by one of the other contributors to the book, with these commentaries providing alternative ways of looking at a particular issue, and encouraging the reader to engage in the debates. Further, the chapters are bite-sized and self-contained, and I enjoyed picking up the book to read, say, a chapter or two, before coming back to it later.
There is an occasional problem with the shortness of the chapters. This is that sometimes there isn’t enough room for ideas to be gently introduced to those of us who aren’t professional mathematicians or philosophers. Despite the book’s aim of being accessible to the layperson, at times it is just too much like an academic book to be considered good popular science.
Some contributions are not as dense as others, however. Marcus du Sautoy, who has perhaps had more practice than some of the other contributors in writing popular science, has written a very easy to follow chapter. And I particularly liked his idea of reconciling creation in mathematics with discovery – whilst all mathematical ideas already exist ‘out there’, in a Platonic sense, waiting to be discovered, mathematicians are still engaged in creative processes, in the sense that they have to choose, often for aesthetic reasons, the most appealing and useful ideas from among the much more banal.
Altogether, then, this is an interesting and thought-provoking collection, which does however suffer from being a little too difficult in parts.
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Review by Matt Chorley

How Pleasure Works – Paul Bloom ****

I have to start this review with a confession and an apology to the author. When the book arrived for review in 2010 (no, not a typo), I was totally fed up with books about different human emotions. We had been absolutely drenched with the things, many of them rather tedious. So I put it to one side and forgot about it. A few days ago I needed a book to read, had nothing else to hand and discovered I’d made a big mistake – because the book is brilliant. So my apologies to Paul Bloom: the only thing I would say is that as an author I appreciate reviews however late they come and I hope he will too.
Bloom makes a wonderful exploration of what pleasure is and why we appreciate everything from basic animal desires like food and sex to much more complex enjoyment like reading a book or looking at an artwork. In doing so he digs into the real attachments we have – why, for example, we appreciate a ‘real’ original painting more than a perfect copy, even though the artwork itself is identical. And why we value a tape measure owned by J. F. Kennedy (one sold for $50,000) more than just an ordinary one off the shelf in a hardware store.
At the heart of Bloom’s argument is the rather philosophical concept of essences. Human beings have a tendency, he argues to associate invisible intangible essences with objects that change their value to us. The fact that in an objective sense these essences don’t exist doesn’t matter to us – and so from a psychological viewpoint they are important and real. If this sounds a little dull and philosophical don’t worry – Bloom’s writing is light and interesting and he makes all this stuff… a pleasure to read.
You may wonder when I think this book is so excellent why it has only got four rather than five stars. This is primarily because the subject, though fascinating, is frankly rather woolly. There is a lot in here that isn’t so much science as philosophy and guesswork (there’s  difference?). Because of that, I hesitate to give it the full whack. But it is a great read, there is fascinating material in there, and I’d really encourage you to give it a go. With the proviso of not giving it to anyone who’d be shocked by the description of S&M etc. it would make a great present too.
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Review by Brian Clegg

Monday, 3 December 2012

Turing: Pioneer of the Information Age – B. Jack Copeland *****

Alan Turing is a name that has grown in stature over the years. When I first got interested in computers all you really heard about was the Turing test – the idea of testing if a computer could think by having a conversation by teletype and seeing if you could tell if there was a computer or a human at the other end. Then came the revelations of the amazing code breaking work at Bletchley Park. Now, though, we know that Turing was much more than this, the single person who most deserves to be called the father of the computer (we allow Babbage to be grandfather).
All this and much more comes through in B. Jack Copeland’s superb biography of Turing. It’s not surprising this book (and its competitors) is on sale now. 2012 is the hundredth anniversary of Turing’s birth. And it is a timely reminder of just how important Turing was to the development of the the technology that is at the heart of much of our everyday lives (including the iPad I’m typing this on today).
If I had to find fault at all with this book, it can be a little summary in some aspects of Turing’s private life – but I suspect this reflects the lack of information from a very private man. However if, like me, you’re a bit of a computer geek it would be impossible not to be fascinated by the description of his ideas and the technology that was developed from them, beautifully written by Copeland. I’ve read plenty before about Enigma, but the section on this was still interesting, and the Tunny material (a later, more sophisticated German coding device, to crack which the Colossus computer was developed) was all new to me.
Similarly, I hadn’t realised how many firsts belong in the UK rather than the US. I knew Turing’s work led to the first stored program electronic computer – the first true computer in a modern sense – but I hadn’t realised, for instance that Turing was the first to write the code for computer generated music, with the first computer music in the world produced using that code in Manchester (contrary to the myths you are likely to see online).
Although some of the personal life information is a little sketchy, Copeland really delivers on Turing’s death. I had always accepted the story that he committed suicide with a poisoned apple as a result of the ‘chemical castration’ he chose as an alternative to prison for admitting homosexual acts. Copeland tears this myth to pieces. Turing had endured the hormone treatment with amusement – and it had finished a year before his death. By then he was fully recovered. He appears to have been happy and positive at the time of his death. He left a part-eaten apple by his bed every night. And he was experimenting on electroplating in a room adjacent to his bedroom – using a solution that gave off hydrogen cyanide. The postmortem was very poor, without testing whether the cyanide that killed him had been ingested or inhaled. The evidence seems strong that Turing’s death was an unfortunate accident, not the tragic suicide that is usually portrayed.
In the end I can strongly recommend that anyone with an interest in computing should rush out and buy a copy of this book. Well written, fascinating and overthrowing a number of myths, it’s a must-have.
Hardback:  
Review by Brian Clegg