Monday, 30 July 2012

What Einstein Kept Under His Hat – Robert L. Wolke ****

First things first – this book has nothing to do with Einstein, for which I ought to dock it several stars for gratuitous use of the great man’s name, but I can’t because it’s such a good book. And it’s about the chemistry of food.
The format is simple. Robert Wolke gives us a series of questions about food that have a chemistry-based answer and… he answers them. Interspersed there are a fair number of recipes, vaguely relevant to the question. And that’s about it. But it’s the way he tells them.
Firstly, Wolke is genuinely funny. I would advise any science writer not to use humour, because on the whole it just doesn’t work. The writer comes across as smug and/or silly. But for some reason, Wolke’s funnies (painful though some of them are) hit the spot for me. Take this from the opening:
What are the first two things a server says to you as soon as you’ve been seated in a restaurant? (1) “Hello, my name is Bruce/Aimee and I’ll be your server.” (2) “May I bring you something to drink?”
Thus far, I have been successful in repressing the replies: (1) “Glad to meet you. My name is Bob and I’ll be your customer.” Or (2) “Thanks, but I came here primarily to eat.”
That sets the tone nicely. (He goes on to point out it would be useful to know your server’s name if it were socially acceptable to yell it across the room when you wanted service… but it isn’t.) Wolke breaks down the food into various sections (drinks, dairy, vegetables) etc. and just piles on the wonderful (and sometimes silly) questions that enable him to explore the subject. I don’t know if he makes the questions up like most magazines (I don’t really care) – but the format works really well and I genuinely learned a lot about how food and cooking work from the viewpoint of a chemist.
A couple of minor moans. It is quite American in feel, with reference to various products Europeans will never have heard of, but it really doesn’t make much difference to the readability and sheer fun of this book. I admit I didn’t read the recipes, but I’m sure they’re nice too. I did notice one oddity. Sometimes (but not always) the recipe calls for ‘kosher salt’. This sounds as bizarre a concept as organic salt. I wish he had a) explained what it was and b) debunked the ‘expensive salts taste better’ myth – and c) pointed out the meaningless of the concept of kosher salt.
Overall, though, a real find. Great summer reading – it’s very light to read – but some genuinely interesting scientific concepts put across well.
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Review by Brian Clegg

Monday, 23 July 2012

Nature’s Nanotech #2 – The magic lotus leaf – Brian Clegg

The second in our Nature’s Nanotech series.
Living things are built on hidden nanotechnology components, but sometimes that technology achieves remarkable things in a very visible way. A great example is the ‘lotus leaf effect.’ This is named after the sacred lotus, the Nelumbo nucifera, an Asian plant that looks a little like a water lily. The plant’s leaves often emerge into the air covered in sticky mud, but when water runs over them they are self cleaning – the mud runs off, leaving a bare leaf exposed to the sunlight.
Water on a Lotus leaf – image from Wikipedia
Other plants have since been discovered to have a similar lotus leaf effect, including the nasturtium, the taro and the prickly pear cactus. Seen close up, the leaves of the sacred lotus are covered in a series of tiny protrusions, like a bad case of goose bumps. A combination of the shape of these projections and a covering of wax makes the surface hydrophobic. This literally means that it fears water, but more accurately, the leaf refuses to get too intimate with the liquid. This shouldn’t be confused with hydrophobia, a term for rabies!
Water is naturally pulled into droplets by the hydrogen bonding that links its molecules and ensures that this essential liquid for life exists on the Earth (without hydrogen bonding, water would boil at around -70 Celsius). This attraction is why raindrops are spherical. They aren’t teardrop shaped as they are often portrayed. Left to their own devices, water drops are spherical because the force of the hydrogen bonding pulls all the molecules in towards each other, but there is no equivalent outward force, so the water naturally forms a sphere.
The surface of the lotus leaf helps water stay in that spherical form, rather than spreading out and wetting the leaf. The result is that the water rolls off, carrying dirt with it, rather like an avalanche picking up rocks as it passes by. Because of the shape of the surface pimples on the leaf, known as papillae, particles of dirt do not stick to the surface well, but instead are more likely to stick to the rolling droplets and be carried away. As well as letting the light through to enable photosynthesis, this effect is beneficial to the leaves as it protects them against incursion by fungi and other predatory growths.
Although the papillae themselves can be as large as 20,000 nanometres tall, the effectiveness of these bumps is in their nanoscale structure, with multiple tiny nobbly bits that reduce the amount of contact area the water has with the surface to a tiny percentage. After the effect was discovered in the 1960s, it seemed inevitable that industry would make use of it and there have been several remarkable applications.
One example that is often used is self-cleaning glass – which seems very reasonable as the requirement is identical to the needs of the lotus leaf – yet strangely, what is used here is entirely different. Pilkington, the British company that invented the float glass process, has such a glass product known as Activ. This has a photo-catalytic material on its surface that helps daylight to break down dirt into small particles, but it also has a surface coating that works in the opposite way to the lotus leaf. It’s an anti-lotus leaf effect.
The coating on this glass, a nanoscale thin film, is hydrophilic rather than hydrophobic. Instead of encouraging water to form into droplets that roll over the glass picking up the dirt as they go, this technology encourages water to slide over the surface in a sheet, sluicing the dirt away. In practice this works best with heavy rainfall, where the lotus effect is better at cleaning surfaces with less of a downpour – but both involve nanoscale modification of the surface to change the way that water molecules interact.
Increasingly now, though, we are seeing true lotus leaf effect inspired products, that make objects hydrophobic. A process like P2i’s Aridion technology applies a nano-scale coating of a fluoro-polymer that keeps water in droplets. The most impressive aspect of this technology is just how flexible it is. Originally used to protect soldiers clothing against chemical attack , the coatings are now being applied to electronic equipment like smartphones, where internal and external components are coated to make them hydrophobic, as well as lifestyle products such as footwear, gloves and hats. Working like self-cleaning glass would be disastrous here. The whole point is to keep the water off the substance, not to get it wetter.
We are really only just starting to see the applications of the lotus leaf effect come to full fruition. For now it is something of a rarity. Arguably it will become as common for a product to have a protective coating as it for it to be coloured with a dye or paint. Particularly for those of us who live in wet climates like the UK, it is hard to see why you wouldn’t want anything you use outdoors to shrug water off easily. I know there have been plenty of times when I have been worriedly rubbing my phone dry on my shirt that I would have loved the lotus leaf effect to have come to my rescue.
Seeing nanotechnology at work in the natural world doesn’t have to help us come up with new products. It could just be a way of understanding better how a remarkable natural phenomenon takes place. In the next article in this series

 I will be looking at a mystery that was unlocked with a better understanding of nature’s nanotech – but one that also has significant commercial implications. How does a gecko cling on to apparently smooth walls?

Sunday, 22 July 2012

Ignorance: How it drives science – Stuart Firestein *****

This is a delightful little book that really gets you thinking. I stress the ‘little’ part not as a negative, but as a good thing. There is nothing worse than fat, bloated popular science books where the author feels they have to get 120,000 words to be taken seriously. This is the sort of book that can be read in a couple of hours – but you will get so much more out of it than one of those tedious doorstops.
The premise underlying the book is in once sense extremely simple, yet is fundamental to an understanding of what science is and what scientists do. And it is an understanding that is totally at odds with the typical way science is portrayed both in university lectures and popular science books. As Stuart Firestein points out, what is important is not the facts, but rather the area of ignorance. The interesting part and the fundamental heart of science is not about what we know, but about what we don’t know and where we want to look next.
Take this lovely quote: ‘Working scientists don’t get bogged down in the factual swamp because they don’t care all that much for facts. It’s not that they discount or ignore them, but rather that they don’t see them as an end in themselves. They don’t stop at the facts; they begin there, right beyond the facts, where the facts run out.’
When I give my talk based on my book Before the Big Bang, I end by talking about dark matter and dark energy, and how our lack of any real idea of what these are means we know very little about the majority of what makes up the universe. And, I stress, this isn’t a bad thing – this is what makes science interesting. Stuart Firestein takes this viewpoint and puts it at the heart of science.
If I have any moan, the introductory section is just a touch repetitive on the central role of ignorance in science, but I think it’s such an important aspect that so few people recognise that it’s well worth hammering home. I also, despite the case histories he gives, find it difficult to follow his explanation for the process of selecting the right bits of ignorance to work on. But overall this is a great book and recommended reading for both scientists and anyone with an interest in science.
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Review by Brian Clegg

Monday, 16 July 2012

Nature’s Nanotech – Brian Clegg

When we think of nanotechnology, it’s easy to jump to the conclusion that we are dealing with the ultimate in artificial manufacturing, the diametric opposite of something that’s natural. Yet in practice, nature is built on nanotechnology. From the day-to-day workings of the components of every single biological cell to the subtle optics of a peacock feather, what we see is nanotechnology at work.
Not only are the very building blocks of nature nanoscale, but natural nanotechnology is a magnificent inspiration for ways to make use of the microscopic to change our lives and environment for the better. By studying how very small things work in the natural world we can invent remarkable new products – and this feature is the first in a series that will explore just how much we can learn and gain from nature’s nanotech.
As I described in The Nanotechnology Myth the term ‘nanotechnology’ originates from the prefix nano- which is simply a billionth. Nanotechnology makes use of objects on the scale of a few nanometres, where a nanometre is a millionth of a millimetre. For comparison, a human hair is around 50,000 nanometres across. Nanotechnology encompasses objects that vary in size from a large molecule to a virus. A bacterium, typically around 1,000 nanometres in size, is around the upper limit of nanoscale items.
A first essential is to understand that although nanotechnology, like chemistry, is involved in the interaction of very small components of matter, it is entirely different from a chemical reaction. Chemistry is about the way those components join together and break apart. Nanotechnology is primarily about their physics – how the components interact. If we think of the analogy of making a bicycle, the ‘chemistry’ of the bicycle is how the individual components bolt together, the ‘nanotechnology’ is how, for example, the gear interacts with the chain or pushing the pedals makes the bike go.
This distinction is necessary to get over the concern some people raise about nature and nanotechnology. A while ago, when I wrote my book on environmental truth and lies, Ecologic, I had a strange argument with a representative of the Soil Association, the UK’s primary organic body. In 2008 the Soil Association banned nanoparticles from their products. But it only banned man-made nanoparticles, claiming that natural ones, like soot, are fine ‘because life has evolved with these.
This is a total misunderstanding of the science. If there are any issues with nanotechnology they are about the physics, not the chemistry of the substance – and there is no sensible physical distinction between a natural nanoparticle and an artificial one. In the case of the Soil Association, the reasoning was revealed when they admitted that they take ‘a principles-based regulatory approach, rather than a case-by-case approach based on scientific information.’ In other words their opposition was a knee-jerk one to words like ‘natural’ and ‘artificial’ rather than based on substance.
Of themselves, like anything else, nanoparticles and nanotechnology in general can be used for bad or for good. Whether natural or artificial they have benefits and disadvantages. A virus, for example, is a purely natural nanotechnology that can be devastatingly destructive to living things. And as we will see, there are plenty of artificial nanotechnologies that bring huge benefits.
In nature, nanotechnology is constructed from large molecules. A molecule is nothing more than a collection of atoms, bonded together to form a structure, which can be as simple as a sodium chloride molecule – one atom each of the elements sodium and chlorine – or as complex as the dual helix of DNA. We don’t always appreciate how significant individual molecules are.
I had a good example of this a few days ago when I helped judge a competition run by the University of the West of England for school teams producing science videos. The topic they were given was the human genome – and the result was a set of very varied videos, some showing a surprising amount of talent. At the awards event I was giving a quick talk to the participants, looking at the essentials of a good science video. I pointed out that they had used a lot of jargon without explaining it – a common enough fault even in mainstream TV science.
Just to highlight this, I picked out a term most of them had used, but none had explained – chromosomes. What, I asked them was a chromosome? They told me what it did, but didn’t know what it was, except that it was a chunk of DNA and each human had 46 of them in most of their cells. This is true, but misses the big point. A chromosome is simply a single molecule of DNA. Nothing more, nothing less. One molecule.
Admittedly a chromosome is a very large molecule. Human chromosome 1 is the biggest molecule we know of, with around 10 billion atoms. Makes salt look a bit feeble. But it is still a molecule. The basic components of the biological mechanisms of everything living, up to an including human beings are molecules. Chromosomes provide one example, effectively information storage molecules with genes as chunks of information strung along a strip of DNA. Then there are proteins, the workhorses of the body. There are neurotransmitters and enzymes, and a whole host of molecules that are the equivalent of gears to the body’s magnificent clockwork. These are the building blocks of natural nanotechnology.
So with a picture of what we’re dealing with we can set out to see nature’s nanotech in action and the first example, in the next feature in this series, will show how nanotechnology on the surface of a leaf has inspired both self-cleaning glass and water resistant trainers.

Saturday, 14 July 2012

The Star Book – Peter Grego ****

This attractive landscape format book combines an excellent introduction to the stars and basic astronomy with a set of star maps, plus in depth looks at some of the stars featured, with a  bonus section on the solar system.
Amazon says it’s a hardback, but in fact it’s a paperback with a rather ingenious cover – you can’t tell from the photo, but the words ‘The Star Book’ are punched through as a series of holes that show the white paper of the next page beneath. Like many astronomy/space books, the cover lacks shelf appeal because it is mostly black, but at least there is some original thought here.
Unlike many books in this format which tend to concentrate on the pictures, there is a good deal of excellent text by Peter Grego, so there was no feeling that you were only getting the star maps and star ‘biographies’, something these days much more suited to an iPad or smartphone app. Instead, the opening 30 or so pages give a very good introduction that would be valuable to any beginning astronomer.
Throughout the pages are on good semi-glossy paper, so the full colour illustrations are better quality than is sometimes achieved. Overall, this book was a very pleasant surprise. It may not be a typical, end-to-end read popular science book but combines genuinely readable, interesting and informative text with a host of practical maps and data. Good stuff.
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Review by Brian Clegg

Tuesday, 10 July 2012

Radioactivity – Marjorie C. Malley ****

Don’t judge a book by its cover, my old gran used to say (and some of the covers of the books she read certainly proved she believed what she said), but in practice it is difficult advice to follow. Covers have a huge impact on our approach to a book – and combined with an old-fashioned feeling title this one screamed ‘dull textbooky kind of thing at me.’ Luckily, though, I resisted the urge to lose it at the bottom of the review pile, because Radiationhas a lot going for it.
Marjorie Malley divides her book into three main sections. The first, biggest, and best gives us the history of the discovery of radioactivity and the development of the theory of what was going on. The second, which is quite interesting, looks at the applications of radioactivity. And the third, which isn’t very interesting at all, seems to be a sort of ‘put radioactivity into context’ that did very little for me. But that doesn’t matter, because that first section is so good.
It’s not that the material itself was all that new to me. I had read plenty, for example, about the Curies and their work, or about Rutherford. But what I found absolutely fascinating – and it’s something I’ve hardly ever come across in popular science writing – is the way that Malley makes us time travellers, g the feel for exactly what people were thinking and saying as work on radioactivity progressed. Instead of getting a sanitised story with a logical building of ideas, we travelled down all sorts of dead ends and incorrect theories. At times it could be quite confusing, not knowing which bits would later be proved correct, but it gave a much better feel for the nature of such scientific discovery than a typical book on the subject.
As a science writer myself I’m in awe of the work that must have gone into getting that changing perspective as we move through the timeline. It’s magnificent. So even though the middle section on applications is rushed and the final section did nothing for me, I’d still highly recommend this slim book for a great insight into an important period and series of events in the history of science.
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Review by Brian Clegg

Saturday, 7 July 2012

The Violinist’s Thumb – Sam Kean ****

I was a great fan of Sam Kean’s The Disappearing Spoon, so it was excellent to see a followup in The Violinist’s Thumb. The violinist in question was Paganini who had a genetic disorder that enabled him to bend his thumb back far beyond the usual limit. And this is an indirect hint about the subject of the book – DNA and our genetic code.
This is, without doubt, a very good book. A quote from New Scientist on the front compares Sam Kean’s writing to that of Bill Bryson – I think this delusional, and possibly a little unfair on Kean. I’d say he is, as a pure writer, better than Bryson, but lacks Bryson’s superb comic touch. Kean attempts humour, but it certainly isn’t up to Bryson – the comparison just doesn’t make sense. The good news is that once again Kean has brought an aspect of science alive with a ton of excellent anecdotes about the individuals involved, in this case in everything from studying the fruit flies that form the fingerprint on the cover of the book to cracking our genetic code in the Human Genome Project.
Along the with, if, like me, you aren’t a biologist you will certainly learn plenty. It might seem trivial but the best thing I went away with was the realisation that in DNA’s base pairs it’s easy to remember that A goes with T and C with G, because the curved letters go together and the straight ones similarly. However, I simply didn’t enjoy it as much as Disappearing Spoon. That book was a page turner that I couldn’t wait to get back to – this was a bit of plough through experience.
This is mostly not Kean’s fault (except for the fact the book is too long, but that might have been imposed on him). It’s the subject. It simply doesn’t have the variety that arose from looking at different elements – here you are on the same single subject throughout. And sometimes, because of this, the entertaining side stories weren’t helpful because I lost track of the theme they interrupted. I also found that because it is a single topic, I really wanted a lot more depth, but Kean continues to skip on, focussing on storytelling not content, telling us things without really explaining them. On a technical issue I would also say that Kean leaves epigenetics too late and should have integrated it more into the rest – as it stands its importance really doesn’t come across.
Overall it’s an excellent book – highly readable and with lots of great stories. It’s just that Kean’s style isn’t quite as suited to this topic as it was to the elements, and so this title is rather overshadowed by its predecessor.
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Review by Brian Clegg

Who Invented the Computer? – Ian Watson

Ian Watson is the author of The Universal Machine and featured in a recent Four Way Interview.
Saturday June 23 2012 was the centenary of the birth of Alan Turing, the troubled genius who invented the modern computer. Why though do so few people recognize his name and his great achievements?
In 1936 English mathematician Alan Turing, published a paper, On Computable Numbers, with an application to the Entscheidungsproblem. This became the foundation of computing. In it Turing presented a theoretical machine that could solve any problem that could be described by instructions encoded on a paper tape. A Turing Machine could calculate square roots, whilst another might solve Sudoku puzzles. Turing demonstrated you could construct a single Universal Machine that could simulate any Turing Machine. One machine solving any problem for which a program could be written – sound familiar? He’d invented the computer.
Then, computers were people who did calculations. As the Allies prepared for WWII they faced a shortage of computers for military calculations. When men left for war the shortage got worse so the US mechanized the problem building the Harvard Mark 1; it could do calculations in seconds that took a person hours. The British also needed mathematicians to crack the Nazi’s Enigma code.
Turing worked at Bletchley Park, perhaps better know as “Station X,” where code-breaking became an industrial process; 12,000 people working 24/7. Although the Polish had cracked Enigma before the war the Nazis had made Enigma more complicated; there were 10114 permutations. Turing designed a machine, called the Bombe, that searched through the permutations and by war’s end the British were reading all Enigma traffic. Historians agree that Turing shortened the war by as much as two years and Churchill would later say that Turing had made the single biggest contribution to Allied victory in the war.
As the 1950s progressed business was quick to use computers and as the technology advanced business computing became an industry. These computers were all universal machines – you could program them to do anything.
There will positively be no internal alteration [of the computer] to be made even if we wish suddenly to switch from calculating the energy levels of the neon atom to the enumeration of groups of order 720. It may appear somewhat puzzling that this can be done. How can one expect a machine to do all this multitudinous variety of things? The answer is that we should consider the machine to be doing something quite simple, namely carrying out orders given to it in a standard form which it is able to understand. – Alan Turing
By the 1970s a generation was born who grew up with “electronic brains;” they wanted their own personal computers. The problem was they had to build them. In 1975 a college dropout called Steve Wozniak built a simple computer around the 8080 microprocessor, which he hooked up to a keyboard and TV. His friend, Steve Jobs, called it the Apple I, and found a Silicon Valley shop that would buy 100 for $500 each. Apple had its first sale and Silicon Valley’s start-up culture was born. Another dropout, Bill Gates, realized that PCs needed software and that people would pay for it – Microsoft would sell them programs.
Turing had another vision, one day computers would think? But, how would you know a computer was intelligent? He devised the Turing Test; a judge sitting at a computer terminal types questions to two entities: a person and a computer. The judge decides which entity is human. If the judge is wrong the computer passes the test and is intelligent.
Artificial intelligence (AI) is entering your daily life. Car satnavs and Google search use AI, Apple’s iPhone can understand your voice and intelligently respond, car manufacturers are developing autonomous cars. Turing’s vision of AI will soon be a reality.
In 1952 Turing was prosecuted for being gay and was sentenced to chemical castration. This caused depression and he committed suicide by eating an apple he’d poisoned. Outside of academia Turing remained virtually unknown because his WWII work was top secret. Slowly word of Turing’s genius spread; in 1999 Time Magazine named him as one of the “100 Most Important People of the 20th Century,” stating: “The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine.” and in 2009 the British Prime Minister issued a public apology:
…on behalf of the British government, and all those who live freely thanks to Alan’s work, I am very proud to say: we’re sorry. You deserved so much better.
Finally Alan Turing is getting the recognition he deserves for inventing the computer, his Universal Machine that has transformed our world and will profoundly influence our futures.

Thursday, 5 July 2012

Congratulations to our editor on Inflight Science

Congratulations to our editor for his book Inflight Science making it to the heady heights on Kindle to rank alongside assorted Shades of Grey:

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Sunday, 1 July 2012

Nature’s Nanotech #3 – Hanging with the Gecko – Brian Clegg


The third in our Nature’s Nanotech series. 
If you’ve ever seen gecko walking up a wall, it’s an uncanny experience. Okay, it’s not a 40 kilo golden retriever, but we are still talking about an animal weighing around 70 grams that can suspend itself from a smooth wall as if it were a fly. For a gecko, even a surface like glass presents no problems. This is nature’s Spiderman.
It might be reasonable to assume that the gecko’s gravity defying feats were down to sucker cups on its feet, a bit like a lizard version of a squid, but the reality is much more interesting. Take a look at a gecko’s toes and you’ll see a series of horizontal pads called setae. Seen close up they look like collections of hairs, but in fact they are the confusingly named ‘processes’ – very thin extensions of the tissue of toe which branch out into vast numbers of nanometer scale bristles.
These tiny projections add up to a huge surface area that is in contact with the wall or other surface the gecko decides to encounter. And that’s the secret of their glue-free adhesion. Because the gecko’s setae are ideally structured to make the most of the van der Waals force. This is a quantum effect resulting from interaction between molecules in the gecko’s foot and the surface.
We are used to atoms being attracted to each other by the electromagnetic force between different charged particles. So, for example, water molecules are attracted to each other by the hydrogen bonding we saw producing spherical water droplets in the previous feature. The relative positive charge on one of the hydrogen atoms is attracted to the relative negative charge on an oxygen. But the van der Waals force is a result of additional attraction after the usual forces that bond atoms together in molecules and hydrogen bonding have been accounted for.
Because of the strange quantum motion of electrons around the outside of an atom, the charge at any point undergoes small fluctuations – van der Waals forces arise when these fluctuations pair up with opposite fluctuations in a nearby atom. The result is a tiny attraction between each of the nanoscale protrusions on the foot and the nearby surface, which add up over the whole of the foot to provide enough force to keep the gecko in place.
Remarkably, if every single protrusion on a typical gecko’s foot was simultaneously in contact with a surface it could keep a heavy human in place – up to around 133 kg. In fact the biggest problem a gecko has is not staying on a surface, but getting its foot off. To make this possible its toes are jointed unusually and it seems to secrete a lubricating fluid that makes it easier to detach its otherwise dry but sticky pads.
Not surprisingly, there is a lot of interest in making use of gecko-style technology. After all, master this approach and you have a form of adhesion that is extremely powerful, yet doesn’t deteriorate with repeated attaching and detaching like a conventional adhesive. A number of universities have been researching the subject.
The first publication seems to have been from the University of Akron in Ohio, where a paper in 2007 described a gecko technology sticky tape with four times the sticking power of a gecko’s foot, meaning fully deployed gecko-sized pads could hold up around half a tonne. With these on its feet, a 40 kilogram golden retriever would have no problem walking up walls – the only difficulty would be managing to apply enough force to detach its paws as it walked. In the tape, the gecko’s setae are replaced by nanotubes of carbon fibre which are attached to a sheet of flexible polymer, acting as the tape.
The great thing about carbon nanotubes, which are effectively long, thin, flexible carbon crystals, is that they can be significantly narrower than the smallest protrusions from a gecko’s foot. A typical nanotube has a diameter of a single nanometer – pure nanotechnology – maximising the opportunity for van der Waals attraction. Within a year, other researchers at the University of Dayton (Ohio again!) were announcing a glue with ten times the sticking power of the gecko’s foot.
Such adhesives are available commercially on a small scale, offering the ability to stick under extreme temperature conditions and to surfaces that are wet or flexible that would defeat practically any conventional adhesive. We can expect to see a lot more gecko tapes (like the Geckskin product) and gecko glues in the future.
There have been other theories to explain the mechanism of the gecko’s foot, including a form of capillary attraction, but the best evidence at the moment is in favour of van der Waals forces. This seems to be borne out by the problem geckos have sticking to Teflon – PTFE has very low van der Waals attractiveness. To find out more about the gecko’s foot (and other technological inspirations from nature) I would recommend the aptly titled The Gecko’s Foot by Peter Forbes.
The action that keeps a gecko in place is a dry application of natural nanotechnology, but the more you look at the nanotech biological world, the more you realize it’s mostly a wet world. In the next feature in this series we’ll look at why conventional ‘dry’ engineering often won’t work on nanoscales and how we need to take a different look at the way we build our technology, bringing liquids into the mix.