Unlike Monday’s wind power video, this one is no joke. In fact it’s testament to the strength of balloon rubber, the force of gravity, fluid mechanics, and high-speed photography. The clip lasts about 32 seconds, but the actual action is taking place in a fraction of that time. Recorded on a Photron
ultima APX at 2000 frames per second. If you view the original high-quality clip you can use the play controller to scroll through the video slowly and observe each stage of the process at your leisure.
“I do so love it when water balloons distort themselves for our viewing pleasure. This one certainly did not disappoint in that regard. The water balloon can be seen undulating in a very odd fashion prior to its equally odd compression and explosion.”
There are a lot of similarly high-speed clips on the makers’ site at http://www.lucidmovement.com/, including a burning lightbulb, a cannonball landing in a pond, compressed air blasted into water, a scanner being dropped from a great height, a jiggling electric light filament, a gasoline (petrol) fireball, a woman running etc etc. There’s a whole category on balloon fun, you get the picture (pardon the pun).
I’m playing catch up, after some offline time last week (holidays, families, and illness), so today’s post is a grab-bag of the various items (mainly books) sitting in a large pile on my desk that I thought deserved a quick mention and a link or two for more information.
First up: Why the Lion Grew Its Mane – a big floppy book with a glossy cover and some wonderful nature photography. Author Lewis Smith (a science reporter for The Times (London) describes it as a miscellany of recent scientific discoveries from astronomy to zoology, and that’s pretty much what you get. Somewhat more esoteric is the cosmic book – The Origins of the Universe for Dummies – from Financial Times writer Stephen Pincock and sci-tech writer Mark Frary. Apparently, this is an easy book about a tough question, written at a time when dark energy, dark matter and the validity of the Big Bang are all offering humanity an array of new questions about the nature of reality. Although I didn’t see mention of ‘branes.
My old friend Kyriacos “KC” Nicolaou and colleague T Montagnon are next up. I have written widely about KC’s organic odyssey over the last (almost) two decades of my career as a science writer, having become fascinated by the incredible ways in which he and his team turn simple starting materials into some of the most complex natural products. In Molecules That Changed The World, Nicolaou and Montagnon provide a brief history of the art of chemical synthesis and its impact on society from aspirin and penicillin (sample PDF chapter) to the anticancer compound Taxol.
Nothing is static in the world of health, and as Brian L Syme suggests in Seasonally Fit, improving fitness and health is not just about diet and exercise, it’s about understanding the “rules of the game”. I must confess to agreeing with many of the critics of this book that it is aimed at too wide an audience but fails to hit the spot for any single group – whether health practitioners, academics, or lay people. Nevertheless, there is a nugget of an idea here – that our health is affected by the seasons – and with a decent ghost writer could become a useful book to add to the library of anyone hoping to understand their health more fully.
Also on my desk – Achieving Sustainable Mobility by Erling Holden (a scientific study of the impact of the European Commission’s 1992 motion), Darwin’s Paradox a novel by Nina Munteneanu (about an intelligent virus), Neuromatrix from Morphonix Inc (a PC game based around rogue nanobots, a kind of Lemmings for the 21st Century).
Finally, I’m thoroughly enjoying Brain Rules by John Medina in which he presents 12 principles for surviving and thriving at work, home, and school. This is not just a book, but has an interactive and augmentative website as well as an accompanying DVD to help you get the most out of your brain.
The lemon battery, it’s a perennial kids science favourite and perfect for a rainy Saturday morning (if it’s not raining why aren’t you kids outside playing instead of surfing the Pipes on the InterWebs, huh?) Anyway, with a single lemon, a few bits of wire, a copper penny, and a zinc-galvanized nail you can generate electricity (just over one volt).
However, one lemon is not enough to light an LED or power a pocket calculator, for that you’ll need not only more voltage but a higher current, which means more power – Power (Watts) equals voltage (in Volts) multiplied by current in Amps. Four lemons produce enough power to make an LED glow dimly. But, that low current is probably not going to be enough to power your iPod, which is a higher current device. For that you will need what is called a lithium-ion battery and iPods (other mp3 players are available) usually come with such a battery built in, so there’s no need to worry about carrying a dozen lemons and a bag of nails with you for portable music.
The following video explains the ins and outs, quite literally, of making a lemon battery, it’s very methodical and shows you the precise steps needed even if the narration is a bit stiff.
More science videos from the same labs available here
Well, not quite, but the wonderfully named Dr Mark Lewney puts on a great show not only as an axe hero extraordinaire but as a high-flying physicist who can explain why his nifty chops and runs sound the way they do. I had a quick e-chat with him the other day and we obtained permission to post his Famelab video from Channel4 on Youtube. So turn your speakers up to 11 and get ready to rock, harmonically, to the physics of heavy metal geetar!
The one thing that lets Dr Rock down is the total lack of a Justin Out of off of The Darkness jumpsuit and chest wig. Oh well, can’t have everything…
On this side of The Atlantic, there is growing interest this week in Jonny Wilkinson’s balls, and more to the point how he kicks them. Wilkinson’s drop goals are testament to his keen understanding of the physics of aerodynamics, fluid mechanics, and possibly even the Bernoulli effect. Perfect fodder for a physics science project.
However, it’s not all about the shape of the ball nor the swing of the leg, according to UK research published this month. The prodigious kicking success of England rugby player Johnny Wilkinson may rely more on what he does with his arms than his legs, according to a paper published in the journal Sports Biomechanics. Scientists at Bath University analysed the kicking techniques of professional and semi-professional rugby players to see which technique is most successful.
They found that players who swing their non-kicking-side arm across their chest as they make contact with the ball are the most accurate kickers, particularly over longer distances. It could be that the increased momentum produced by this arm movement helps the kicker control the amount of rotation in their bodies so that when they kick the ball their body is facing the target for longer.
Although Wilkinson’s trademark posture in lining up for the kick is well known, it is his arm movement you should watch out for in Saturday’s Rugby World Cup final, it might just signal defeat for the Springboks. Or, maybe that’s just wishful thinking on my part. Two RWC victories in a row, could it happen, could England swing it?
This year’s Nobel Prize for Physics went to Albert Fert (France) and Peter Grünberg (Germany), who share the prize fifty:fifty for their discovery of giant magnetoresistance in which a very weak magnetic change gived rise to a major difference in electrical resistance of a system.
This effect underpins the technology that is used to read data on hard disks. It is thanks to their discovery that it has been possible to miniaturize hard disks so radically in recent years. Sensitive read-out heads are needed to be able to read data from the compact hard disks used in laptops and mp3 players, for instance.
Have you ever wondered what it would be like to make a dollar bill smoothie? Well popular science guru Steve Spangler certainly did and with the help of a super powerful neodymium magnet he demonstrates in the video below just how much iron you would get if you were stupid enough to drink the smoothie. The iron is present in certain magnetic inks used to print a fistful of dollars.
There’s iron in them there bills…you might say!
So, now you’ve watched the video, you’re probably wondering, what are neodymium, or rare earth magnets and why is it so much stronger than a standard fridge magnet? Well, unlike conventional ferric or iron magnets, neodymium magnets are composed of iron, boron, and as the name would suggest, neodymium. The general chemical formula for this alloy is Nd2Fe14B which basically means for every 14 iron atoms in the material there are two neodymium atoms and one boron atom. That special blend (pardon the pun), however, means they can be up to about twenty times stronger than conventional ceramic magnets. Check out the HowStuffWorks site for a simplistic explanation of magnetism.
I asked magnetic expert (soon to be) Dr James Stephenson, who has probably forgotten more about magnets than I ever knew, why it is that the neodymium, or neo, magnets are so much stronger. The strength of a permanent magnet is down to how strong are the individual magnetic moments of the atoms from which it is composed and that’s down to how many electrons can be aligned in each atom, he explains.
Put simply, “Rare-earth magnets, also known as nib magnets, are stronger because the individual atomic magnetic moments are stronger and that adds up to a stronger magnetic field overall,” he says. Taken individually, an isolated atom of a rare earth element, such as neodymium, has gaps in its so-called d [electron] f-shell. When Nd is alloyed with boron and iron those gaps get filled up to a maximum of 14 electrons in the f-shell of each Nd atom, this results in a very strong dipole. “In other words,” Stephenson adds, “more electrons means more current and as a result the magnetic field due to each dipole is higher.” So, there you have it.
By the way, it’s not illegal to blend a dollar bill unless you plan on trying to spend it later, but to be on the safe side bring a friend along, not only can you make sure it’s their dollar bill you blend, but you can claim it was their idea when the FBI turn up at the door too!
Sciencebase Exclusive – Careful experimentation and theoretical analysis of a double-slit experiment have finally quashed a controversy in fundamental physics — the complementarity-uncertainty debate.
Ever since the catflap to the quantum world was opened up to us and Schrödinger’s feline friend was idiomatically let out of the bag, to mix a metaphor or two, there have been more questions and controversies raised than conundrums solved in the world of the very, very small. How can something be both particle and wave, for instance? What allows particles of matter to tunnel through solid objects? And, how is the interference pattern destroyed in a double-slit experiment when measurements are performed on the path traversed by a particle?
What is a double slit experiment, you ask? Well, traditionally, Young’s double-slit experiment consists of shining a light through two narrow, closely spaced slits and observing the results on a screen placed beyond the slits.
Intuitively, you might think that the result would simply be two bright lines, aligned with the slits, representing where the light passes through the slits and hits the card. However, this is not seen in practice, instead, the light is diffracted by the slits and produces fringes corresponding to wave-like interference pattern. The fringes of light and dark regions correspond to where either the light waves constructively (add) and destructively (subtract) from each other. Two peaks in the light wave meet to make a brighter fringe whereas a dark fringe is formed when a peak and a trough coincide. This result seemingly settles a three-century conundrum about whether light is particle or wave, showing apparently that it is a wave.
However, a similar experiment carried out with beams of electrons or atoms fired through the slits produces a very similar interference pattern. How could that be? Particles are solid objects, surely? Well, the double-slit experiment shows that they are not. They produce an interference pattern, which suggests that the particles behave as waves.
The double-slit experiments work perfectly well and reveals interference patterns with light, electrons, and beams of other particles, but only if the experimenter does not try to find out through which slit a particular wave-particle passed before hitting the screen. Try to fire particles through the slits one at a time and as illustratd in the 5-minute video below, you will still see an interference pattern. It is as if each particle passes through both slits simultaneously, each slit individually and together and neither slit all at the same time; behaving some as waves…
As if this were not complicated enough, physicists reasoned that if they could discover which slit the individual particle really goes through each time in this experiment, they could solve the problem. So, they put a measuring device next to one slot and observed what happens as particles are fired through the slits one at a time. Astoundingly, the interference pattern disappears, simply having a measuring device present to observe the route taken by the particles somehow disturbs their wave-like nature and they revert to being tiny, solid objects and produce just two bands on the screen as if they were tiny marbles rather than wave. How could the particles know they were being watched.
This loss of interference has been explained by several of the biggest names in twentieth century physics, among them Niels Bohr and Richard Feynman. They suggested that whenever the path is measured within the double-slit, the momentum of the wave-particle is uncontrollably and irreversibly disturbed. Think about it, it has to be affected by the observer somehow because the very act of observing involves some kind of sharing of information either via photons, charge, energy or matter. This process “washes out” the interference fringes.
Most physicists simply accept this as being precisely what happens. It is a little vague and some might say “handwaving” because it does not pin down the nature of this washing out nor say anything about how the momentum is disturbed by the transaction between observer and observed. More precisely, it is simply what happens because of the back-reaction resulting from the Heisenberg uncertainty relation that says we cannot know simultaneously both the energy and position of any quantum wave or particle with absolute precision. While that kind of folds the argument into a loop, Feynman famously pointed out that, ‘No one has ever thought of a way around the uncertainty principle.’
But, not everyone was happy with this. In 1991, Marlan Scully, Berthold-Georg Englert, and Herbert Walther (Nature 1991, 351, 111) suggested that a microscopic pointer could be used to carry out the observation in such a way that the very act of observation would not disturb the momentum of the particle and so bypass the uncontrollable and irreversible effects suggested by Bohr that leads to interference breakdown. However, Pippa Storey, Sze Tan, Matthew Collett, and Daniel Walls (Nature, 1994, 367, 626), countered this argument, demonstrating that no matter how small the observer nor how the measurements are made, momentum is affected and the interference pattern would disappear. A long and controversial debate has raged between the two scientific factions that back either the Scully or Walls teams.
A theoretical solution was posited by Howard Wiseman and colleagues in 2003 (Phys Rev A, 2003, 311, 285) and refined in 2004 (J. Opt. B: Quant. Semiclass. Opt. 2004, 6, S506-S517). Now, in a seminal paper published today in the New Journal of Physics, Aephraim Steinberg together with Wiseman and colleagues Mir, Lundeen, Mitchell, and Garretson have applied the theory in a novel double-slit setup. Their experimental results suggest that, as is the way with all things quantum, both camps are equally correct and equally wrong. Somehow, you can have your quantum cake and eat it.
They found that by using only weak measurements, they can directly observe the momentum transfer that causes interference breakdown but equally do so without disturbing the two-slit superposition. They effectively verify both the Scully and Walls views. In terms of the Scully position, the team shows that there is no change in the mean momentum, or the mean energy, whereas with respect to the Walls work, they show that the momentum is spread, as one would expect given the uncertainty inherent in the quantum world, according to Heisenberg’s principle.
Feynman always held that the double-slit setup was central to quantum theory, but would never be fully understood. This work by Wiseman and colleagues shows that the humble double-slit experiment can still throw up new quantum mysteries to baffle us.
It is not so long ago, that the first thing that sprang to mind when one read the phrase ‘quantum dot’ was the idea of some rather esoteric and complicated aspect of avant garde physics. This is still partly true, there is some rather complex experimental work underway underpinned by even more complex theoretical work investigating the bizarre properties of tiny devices that can trap a single electron in zero-dimensions.
Practical applications of quantum dots have emerged recently in sensor science but US and Brazilian researchers hope to exploit them in a new kind of electronics, known as spintronics where electron charge and quantum spin add an extra dimension to electronic operations and computation. Spin currents might also be used to allow quantum communications take place “in-chip” in devices so small that light propagation is not practical. Such developments will open up quantum dots that can increase processing speed, storage capacity, and functionality of conventional electronics, communication, and computations and technologies.
Eduardo Mucciolo of the Department of Physics at the University of Central Florida, Orlando and Caio Lewenkopf of the Department of Theoretical Physics at State University of Rio de Janeiro, Brazil, are investigating lateral semiconductor quantum dots. They believe that such devices could be used as pumps to produce spin polarised currents, by exploring quantum phase coherence phenomena. The effect, called pure spin pumping, is analogous to charging a battery in conventional electronics. Such a spin pump might provide the much-needed circuit element for spin-based electronics.
Writing in the International Journal of Nanotechnology (2007, 4, 482-495), Mucciolo and Lewenkopf describe a lateral semiconductor quantum dot. In these systems, electrons within a two-dimensional gas are trapped within small puddles by the application of a voltage; applied voltages control the shape and size of these puddles. Electrodes can be used to vary the width of the point contacts between the electron puddle and the 2D gas. Controlling these point contacts allows quantum dots to be “opened” and “closed”.
Controlling these point contacts allows them to “open” and “close” the quantum dots. This effect dates back to the early 1990s, points out Mucciolo. “Closing and opening the propagation through a constriction, the point contact, can be used to detect spin-polarized currents,” he explains, “This is how Susan Watson and colleagues at Middlebury College managed to see spin currents coming out of their quantum dot pump in 2003.”
“Recently, our spin pump proposal passed its first experimental test,” say the researchers, who now hope that other teams will take up the challenge and investigate the potential of spin pump quantum dots.
“The main idea behind the spin pumping mechanism was actually published for the first time in Physical Review Letters in a paper I co-authored with Claudio Chamon (Boston University) and Charles Marcus (Harvard University),” adds Mucciolo. The main development since that earlier work presented in the current paper with Lewenkopf is that now they have carried out a much more detailed analysis to demonstrate the precise details, this was entirely missing from the PRL paper, Mucciolo told us. “In the J Nanotech paper we also develop a general formalism that could serve as a basis for the theoretical investigation of several aspects of spin pumps which, albeit important, have not yet been considered in the literature,” Mucciolo adds.
I’m on a photography course this week, hence the leaner, meaner Sciencebase posting regime. But, I did find time to chat with technology writer Wayne Smallman on Blah Blah Tech, who pointed out this neat video showing three distinct coloured fluids (dyed corn syrup) being poured into a vessel stirred slowly and then the flow reversed.
You might suspect it is a trick, but it is not. The three coloured liquids end up separated but are not quite as perfectly aligned as they were at the start. Why does this happen? It’s laminar (non-mixing) reverse flow, is tied to the viscous nature of the corn syrup, the smooth flow of the mix and the reverse unmix. I guess the only trick might be that the three fluids are within a thin layer inside the cylinder within which is a second concentric cylinder, the stirrer, oh that and the fact that the “experimenter” cannot actually count! But the essential thing is that corn syrup has a low Reynolds number (this approximates to high viscosity).
Such effects do occur in nature at tidal river confluences where water from different flows barely mix because of differing temperatures and salt concentration. The same phenomena could underlie the seemingly stable patterns we see on Jupiter (it’s lots of viscous layers not mixing).
Anyway, here’s the video
As to what Wayne had to say about it. “Wow, well effin’ weird, or what?!” were his first words. He figured my “science know-how” would do it more justice. Well, personally, I think it’s just effin’ weird too! Seriously, for a more detailed explanation check out this page on the Harvard website. The video has also been discussed on StumbleUpon here.
I’m playing catch up, after some offline time last week (holidays, families, and illness), so today’s post is a grab-bag of the various items (mainly books) sitting in a large pile on my desk that I thought deserved a quick mention and a link or two for more information.
The lemon battery, it’s a perennial kids science favourite and perfect for a rainy Saturday morning (if it’s not raining why aren’t you kids outside playing instead of surfing the 
Marlan Scully, Berthold-Georg Englert, and Herbert Walther (Nature 1991, 351, 111) suggested that a microscopic pointer could be used to carry out the observation in such a way that the very act of observation would not disturb the momentum of the particle and so bypass the uncontrollable and irreversible effects suggested by Bohr that leads to interference breakdown. However, Pippa Storey, Sze Tan, Matthew Collett, and Daniel Walls (Nature, 1994, 367, 626), countered this argument, demonstrating that no matter how small the observer nor how the measurements are made, momentum is affected and the interference pattern would disappear. A long and controversial debate has raged between the two scientific factions that back either the Scully or Walls teams.
Howard Wiseman and colleagues in 2003 (Phys Rev A, 2003, 311, 285) and refined in 2004 (J. Opt. B: Quant. Semiclass. Opt. 2004, 6, S506-S517). Now, in a seminal paper published today in the New Journal of Physics, Aephraim Steinberg together with Wiseman and colleagues Mir, Lundeen, Mitchell, and Garretson have applied the theory in a novel double-slit setup. Their experimental results suggest that, as is the way with all things quantum, both camps are equally correct and equally wrong. Somehow, you can have your quantum cake and eat it.
It is not so long ago, that the first thing that sprang to mind when one read the phrase ‘quantum dot’ was the idea of some rather esoteric and complicated aspect of avant garde physics. This is still partly true, there is some rather complex experimental work underway underpinned by even more complex theoretical work investigating the bizarre properties of tiny devices that can trap a single electron in zero-dimensions.