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Physics on film

physicsworld.com's multimedia channel features exclusive video interviews with leading figures in the physics community.

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March 2011 Archives

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Courtesy: Jason Rowe/Kepler Mission/NASA

By James Dacey

Since it was launched just over two years ago, NASA’s Kepler mission has discovered 1235 planet candidates, including the recent hoard of six planets orbiting the same star. Pretty impressive, since before NASA’s planet hunter took to the skies we knew of just 330 planets most of which were solitary gas giants.

Today, NASA’s astronomy picture of the day is an attempt to visualize this glut of exoplanets and the range of different stars they orbit. The intriguing image, created by Jason Rowe from the Kepler science team, shows all 1235 candidate planets in transit with their parent stars ordered by size from top left to bottom right.

The Kepler telescope looks for slight dimming in the light of a star as a planet sweeps across our line of vision from Earth. In Rowe’s depiction, these transits are seen as silhouettes on the stellar discs, which reflect the true relative scales of the planets to their suns. Some dots are particularly small but you can get a clearer view if you click through to the original image.

Moving pictures

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By Joe McEntee

Where to start? What to watch? What to watch it on? In the brave, new cross-platform world of iPads, smarter smartphones, Internet-enabled TVs and the like, channel surfing is no longer just a matter of putting your feet up and grabbing the remote.

Consider the latest service offering from New Journal of Physics (NJP), an open-access journal co-owned by the Institute of Physics and the Deutsche Physikalische Gesellschaft and published by IOP Publishing (which also publishes physicsworld.com).

With the launch of its video-abstracts channel last month, NJP is shaping up as a prime destination for a new wave of scientifically minded channel-surfers – students, researchers and educators who like their content open and with plenty of added value thrown in.

It’s early days, but the video service is already winning plaudits from authors and viewers alike. “A great way to communicate our excitement and enthusiasm,” notes one early-adopter, while another adds that the video-abstract format makes the paper “more visible and accessible and is ideal for outreach”.

How all this plays out in the battle for online clicks and eyeballs remains to be seen, though in its favour NJP’s cross-disciplinary remit does map well against a broad chunk of the physics community. Press play on the latest videos and you’ll encounter everything from modelling of the financial crisis through the whispering-gallery effect in neutron scattering to the survival of competing languages.

My own favourite is this piece on nanoscale effects in amorphous carbon:

More TV, where you want it, when you need it. All you need to do now is figure out whether to watch those abstracts on your sleek new iPad2 or your laptop.

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By Hamish Johnston

Physicists are usually a law-abiding bunch, so I was shocked when a group at the APS March Meeting in Dallas, Texas announced that they were going to “break in” to the old Superconducting Super Collider (SSC) site just south of town.

Well, they did manage to get in and they have posted photographs on the web to prove it. There’s something very sad about the photos of the derelict site, especially when contrasted with pictures taken 20 years ago.

Conceived in 1983, the SSC was going to be the next big particle collider with a circumference of 87 km and a maximum collision energy of 40 TeV. That’s as big as Texas compared to the 27 km and 14 TeV of the Large Hadron Collider.

But 10 years later the project was cancelled, leaving a few buildings on the surface as well as tens of kilometres of tunnels deep underground. According to the clandestine team, the tunnels are well below the water table and therefore flooded long ago.

I was tempted to write a blog about the escapade as it played out last week – particularly when the team phoned the press room for directions – but I thought I’d better not tip off the sheriff and his buddies.

When you go down the SSC to have a little fun,
have your ten dollars ready when the policeman comes

They’ll find no Higgs boson,
cause Texas has them SSC blues

They’ll find no Higgs boson,
cause Texas has them SSC blues

Hmm, that’s one for next year’s APS sing-along (to the tune of Deep Elm blues of course)!

Fukushima tops nuclear bill in Dallas

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By Susan Curtis at the APS March Meeting in Dallas

Harold Macmillan, British Prime Minister from 1956 to 1963, once famously said that the biggest challenge facing politicians was “Events, dear boy, events”. Little did the American Physical Society (APS) know that those same words would apply to session H5, entitled “Drowning in carbon: the imperative of nuclear power”, when it was conceived some nine months ago.

Unsurprisingly, the events at the Fukushima Daiichi nuclear reactor in Japan reverberated through the entire session. Most telling was that Toshikazu Suzuki of Japan’s National Institute of Radiological Sciences, who had been due to speak on the country’s nuclear programme, was unable to attend because of his responsibilities in Japan.

Other speakers and commentators focused on the partial meltdown at Fukushima, as well as the impact that such a serious incident will have on nuclear-power programmes in other parts of the world. Ray Orbach, former under-secretary for science at the US Department of Energy and now director of the Energy Institute at the University of Texas at Austin, had originally planned to talk about the disposal of spent nuclear fuel, but instead gave a detailed commentary on the damage sustained by the Fukushima reactor and lessons for similar reactors in other parts of the world.

According to Orbach, the reactor shut down safely immediately after the earthquake, but it was the subsequent tsunami that caused the emergency power generators to fail – and with them the water-based cooling system used to store spent nuclear fuel rods. But he questioned why it took more than two days for the reactor’s operator, the Tokyo Electric Power Company (TEPCO), to start injecting seawater into the core to stop the fuel rods from overheating.

“Why did they wait so long?” he asked. “Well of course you ruin the reactor when you do it. It’s also a question of the power company not wanting to admit that all else has failed.”

TEPCO was also criticized for keeping a large inventory of spent fuel rods in cooling ponds on the reactor site. Fuel rods are normally water-cooled for a number of years before being transferred to dry concrete casks for off-site storage, but at Fukushima the number of spent fuel rods in the cooling ponds had accumulated because of delays in building an off-site reprocessing facility.

Despite these issues, Orbach offered some technical solutions to improve safety at similar reactors in other parts of the world. Top of the list is to introduce passive cooling for spent fuel storage ponds, which would be unaffected by any disruption to the power supply.

That theme was picked up by Robert Rosner of the University of Chicago, who was also director of the Argonne National Laboratory from 2005 to 2009. Rosner argued that the US has reached a pivotal time in its use of nuclear energy. There are currently 104 nuclear power plants operating in the US, but there have been no new starts since 1977 – largely because of public concern over safety.

“We need to choose whether to only focus on regulation – or even stop nuclear altogether – or to spend some money to identify and fix the safety problems,” he told the meeting. With US funding for energy research falling, and an even more suspicious public in the wake of Fukushima, could it be that the balance is tipping away from nuclear – at least in the US?

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By Hamish Johnston at the APS March Meeting in Dallas

I don’t know how I resisted for all these years now that I’ve experienced the physics sing-along here at the March Meeting.

Pictured above is Walter Smith of Haverford College who leads the sing-along every year since 2006

The event is actually a resurrection of an old tradition that goes back to the early 20th century.

My favourite has got to be “I’ve got a lock-in amplifier” with words by Marian McKenzie, who is married to Smith. It’s sung to the tune of “Brand new key” by Melanie – or “I’ve got a brand new combine harvester” to those who live in the West Country.

Choice lines include:

My electrometer is state of the art,
My AFM could warm the clammiest heart,
I saw your post-doc, he was ogling my racks,
I’m writing up some really killer abstracts, oh,

I’ve got a lock-in amplifier,
You’ve got a laser beam.

Other classics included “Bardeen, so keen” to the tune of the Beatles’ “Michelle” and “Energy Eigenstates” in the style of Stephen Sondheim’s “A comedy tonight”.

Walter has an archive of physics songs that goes back to 1947. You can search the archive and read about the songs sung by J J Thompson and others at the Cavendish Lab in Cambridge here.

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By Hamish Johnston at the APS March Meeting in Dallas

Everyone “in the know” knows that the IOP Publishing reception is the best party in town. The food was a fantastic mix of Tex-Mex and classic Italian and the wine was flowing. And where else can you chat about topics as diverse as thermoelectrics, information storage in DNA and the current state of theoretical physics in the UK?

This year there was one more reason to go to the reception: three lucky partygoers won annual IOPimembership from the Institute of Physics. This means that they will receive the new-and-improved digital version of Physics World for a year plus access to past issues, our video archive and more.

You can find out more about becoming an IOPimember here.

More photos from the reception and details of how IOP Publishing is celebrating the centenary of superconductivity can be found here.

By Matin Durrani

For those of you wondering where we get all our ideas for news stories on physicsworld.com from, well obviously we have a bulging contacts book, we scour many of the leading journals, and we keep tabs on all of the key scientific experiments, facilities and space missions.

But, like all journalists, we do rely as well on press releases, including those supplied by the Alphagalileo service, which lists many of the latest releases from institutions in Europe, and those from a similar US-based service called EurekAlert! from the American Association for the Advancement of Science.

Now, EurekAlert! has revealed which press releases posted on its website were looked at most by journalists during 2010.

Nine of the top 10 were in biology and the biosciences, but the winner is one related to physics.

Curiously, it has nothing to do with anything that we at physicsworld.com would regard as all that significant – say the search for extrasolar planets or the hunt for the Higgs – and it certainly didn’t come anywhere near to making our list of the top 10 breakthroughs of 2010.

No, the top press released accessed by journalists on EurekAlert! was on a relatively obscure branch of physics. It concerned evidence, presented in the journal Science, that an unusual form of symmetry known as E8 – which a small number physicists believe underlies a theory of everything – may have been spotted in a solid material for the first time.

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We wrote about the paper at the time in January last year, which you can read here.

The paper may have proved so popular because it claimed to have shown that this 8D symmetry group describes the spectrum of spin configurations that emerge when a 1D chain of spins is chilled to near absolute zero and subjected to a specific magnetic field. The finding also suggested that the idea of a “golden mean” – previously only seen in mathematics and the arts – also exists in solid matter on the nanoscale.

But – and I’m guessing here – it may actually have been because journalists remember a controversial (and unrefereed) paper on E8, entitled “An exceptionally simple theory of everything” by an obscure, independent physicist called Garret Lisi, who is a keen surfer and does not follow a conventional academic life. Those traits – and some pretty pictures associated with E8 symmetry – led to a fair amount of press coverage, and far more than many string theorists felt, and still feel, it deserves.

In their view, this latest accolade from EurekAlert! will probably only make the situation worse.

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By Hamish Johnston

That’s Paul Grant (right) holding one of the high-temperature superconductor demonstration kits that he and his colleagues developed at IBM’s Almaden lab. The idea is that you fill the reservoir with liquid nitrogen and then place a magnet above the superconductor, where it will float.

The kit that Paul is holding was made in 1987 for IBM board members – and if you look at the photograph below you can see “IBM” embossed on the disc of a YBCO superconductor.

But as a 1987 New Scientist article by Grant points out, it’s not that difficult to make your own high-Tc material.

The article describes how Grant’s daughter Heidi (pictured in the clipping held by Grant) and her high-school classmates were able to make their own YBCO superconductor – and then float a magnet over it.

Reading the article I had a strong sense of deja vu. I had just been in a press conference where Kostya Novoselov was asked why graphene research took off like a rocket after he and Andre Geim worked out a way of making stand-alone sheets of the material. His answer was that it was fairly straightforward to make large high-quality samples of graphene and study its many properties.

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But that’s where the similarity ends. Although physicists don’t understand everything about graphene, many properties have proven to be exactly as predicted by theory.

The same can’t be said about high-Tc superconductors, which have surprised and confounded physicists for 25 years. That was the subject of a talk today by the University of California’s Bob Dynes. “I will be surprised if there are no more surprises,” said Dynes.

By Susan Curtis at the APS March Meting in Dallas, Texas

It was good to see representatives from the Physical Society of Japan at the APS March Meeting. Keizo Murata of Osaka City University, who is also editor of the Journal of the Physical Society of Japan (JPSJ), wanted us to pass this message on to anyone in the physics community who wishes to make a donation to the relief efforts following the earthquake and tsunami:

“We, the Physical Society of Japan and the JPSJ, deeply appreciate the encouragement we have received from our colleagues all over the world.

“We welcome your donations to the relief and recovery from Japan’s disaster in March 2011. To help this, as well as to avoid any problems with currency exchange, we recommend that you make your donations via authorized organizations in your own country, such as the American Red Cross.

“However, to share your warm sympathy with the worldwide physics community, we would like to recognize your donation. This will be sure to encourage members of the Physical Society of Japan and people around us.

“To achieve this:

1. Send an e-mail to save.japan3.11@jps.or.jp with the subject: “donation Japan disaster” and your name.

2. In the e-mail please note in this order:

• Your name
• Your email address
• Your institution/affiliation
• Your country
• Value of donation (optional)
• The organization that took your donation
• Date of donation
• Any message (optional)
• Permission to use your message with your name on our site (yes/no)

3. If you should make further donations, please send another e-mail to save.japan3.11@jps.or.jp but include “your name (nth time)” in the email.

“Thank you for your kind co-operation,

The Physical Society of Japan
The Journal of the Physical Society of Japan

Murata also told us that JPSJ is still offering online services as normal, although some publications may be rescheduled.

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By Hamish Johnston at the APS March Meeting in Dallas

One of the people in the photo (right) is a robot called Philip K Dick, and the other is David Hanson of Hanson Robotics, which is located just outside of Dallas.

David was talking at the March Meeting about the challenges of making robots that are more lifelike. And not just superficial looks – he’s put a great deal of effort into getting facial expressions right and generally making the robot respond as if it is human.

The problem today is that lifelike robots tend to be creepy (I believe that is a technical term in the industry). This is because getting just a few minor things wrong about how the machine behaves puts it in an uncomfortable place between living and dead – at least, that’s my opinion.

So when will you meet the first robot that is so lifelike that you think it’s human? Hanson thinks it will happen in less than an decade.

I don’t know about you, but that’s creepy!

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By Hamish Johnston at the APS March Meeting in Dallas

It’s the second day of the March Meeting and I’ve just done three video interviews, which should start appearing on physicsworld.com in April.

I also managed to make it to a few press conferences, including one on how to make extremely small transistors and antennas.

Above you can see Mark Reed of Yale University who was the first to create a transistor from a single molecule. Reed and colleagues place an organic molecule between two electrodes, which function as the source and drain in a field-effect transistor. The molecule is suspended above a third electrode, which acts as the gate.

You might think that Reed wants to make these tiny resistors to ensure that Moore’s law – the relentless miniaturization of computer chips – continues right down to the molecular level. However, he points out that the biggest threat to Moore’s law today is how to get rid of all the heat generated by a dense clump of tiny transistors. The molecular transistor doesn’t help much with that, and Reed is more interested in studying the fundamental physics of these quantum devices.

Also speaking at the press conference was Niek van Hulst of the Institute of Photonics Science in Barcelona. Van Hulst and colleagues have made tiny antennas that can broadcast and receive visible light.

Such antennas could be put very close to a molecule of interest for example, and capture all the light emitted by the molecule. Conversely it could also be used to direct intense light at just one molecule. Both of these abilities could prove very useful for molecular spectroscopy.

The team has also managed to put a tiny antenna on a scanning tunnelling microscope (STM) tip. Since the antenna is much smaller than the wavelength of the light it emits, such a set-up could be used to image molecules with resolutions much smaller than the wavelength of the light – beating the diffraction limit.

The most beautiful application though, was using an array of antennas coupled to quantum dots, which broadcast the flickering light of quantum noise within the dots.

By Matin Durrani

radioactivity_chart.png The impact of the earthquake and subsequent tsunami that hit Japan earlier this month has been truly devastating, with the latest reports suggesting 9000 people have died and a further 13,000 currently unaccounted for.

But if you spend your days following media reports of the disaster, you’d be forgiven for thinking that the biggest catastrophe has been the damage to the Fukushima Daiichi nuclear plant.

I’ve sometimes felt as if the mainstream media almost want an epic nuclear disaster to take place so that they have something to get their teeth into and fill their rolling TV news bulletins.

I was therefore pleased to see a sober assessment of the true nuclear danger from the plant from a recent blog entry by Randall Munroe, a physics graduate best known for his comic-strip website xkcd.

The picture above, which you’ll need to click here to see in full, tries to quantify to the best of Munroe’s ability the real risks from the plant.

Sure, it would be great if the reactor had survived the earthquake and tsunami – and there’s no harm making sure other reactors around the world are as safe as they can be as many countries are doing – but this shouldn’t be the signal for the world to end the recent revival in nuclear power.

You only have to think about the damage caused by the BP oil spill in the Gulf of Mexico last year to see a true environmental disaster.

Of course, the Achilles heel of the nuclear industry is the fear of “radiation” and ionizing radiation in particular. You can’t see it or smell it, which makes it, to some at least, creepily scary.

But hopefully Munroe’s chart puts things in perspective a bit.

In the meantime, we’ll continue to follow how the quake is affecting Japan’s physics community. Things are looking not too bad and the odd bent beamline is far from catastrophic given what else has been taking place.

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By Hamish Johnston at the APS March Meeting in Dallas

Will graphene replace silicon as the material of choice for electronics? Many folks have been asking that question since graphene became the latest “wonder material”.

Walter de Heer of the Georgia Institute of Technology answered the question with the above slide.

Just as people and goods are moved by both ships and aeroplanes, De Heer believes that there will be a place for both materials in the future.

While many physicists are trying to develop conventional transistors that use graphene as the semiconductor – essentially replacing silicon – De Heer believes that the wonder material could be used in devices that take advantage of the fact that current is quantized in very narrow ribbons of graphene. This means that quantum interference effects at junctions between ribbons could be used to switch current on and off.

Such transistors would be fundamentally different from conventional devices and immediately made me think of quantum-computing applications. This is possible in principle, according to De Heer, but couldn’t be done at room temperature. This is because the coherence lengths of the devices would be too short – although long enough to achieve switching at junctions.

However, if the junctions were cooled down, the coherence lengths could be long enough for quantum computing. Indeed, De Heer believes that ultimately there will be a place for a material as pure as graphene in quantum computers – perhaps in devices that exploit electron spin.

Photons as qubits

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By Hamish Johnston at the APS March Meeting in Dallas

I spent most of this morning filming 60 second interview spots with top physicists, so I haven’t really got into the swing of things in terms of sessions. Those spots, by the way, should be available on physicsworld.com sometime soon.

I did manage to see a session this morning about silicon qubits. One of the speakers was Jeremy O’Brien of the University of Bristol. Jeremy’s talk was slightly off-topic because he spoke about integrated silicon-based devices that make use of photon as qubits. You can read more about Jeremy’s devices here.

His talk included a nice slide about applications of photon qubits. Quantum metrology is one application that fascinates me. It could be used to do everything from making better optical discs to helping physicists detect gravitational waves.

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By Hamish Johnston at the APS March Meeting in Dallas

I’m here in Dallas for the March Meeting of the American Physical Society, which this year will be celebrating the 100th anniversary of the discovery of superconductivity and the 25th anniversary of high-temperature superconductivity.

Eager to get stuck into superconductivity I went to a session on Sunday on industrial physics that, among other things, asked what we could be doing to get more practical use out of superconductors.

And in case you are wondering when physicists will get round to finding a theory for high-Tc superconductivity, Seamus Davis of Cornell University predicted that it will arrive next year – although I think he was being slightly tongue-in-cheek.

On Saturday I did some sightseeing in Fort Worth. After seeing the cowpokes at the stockyard and having some tasty Texas BBQ, we went to the Fort Worth Museum of Science and History.

One physics-related highlight was an exhibit that looked at the geophysics of natural gas exploration. The impressive vehicle above is used to vibrate the ground, sending soundwaves deep into the Earth – a process called vibroseis. These waves reflect off various geological features and are then picked up by an array of microphones back on the surface. After some impressive computer processing, the data are rendered as a 3D image.

Some of the display was focused on the controversial process of hydraulic fracturing or “fracking”. This involves pumping water and a small amount of sand into gas-bearing rock – the pressure of the fluid fractures the rock and the sand props open the cracks. Gas can then escape along the borehole to the surface.

What the exhibit didn’t seem to discuss is the growing controversy surrounding the process. There seemed to be no mention of the concern of some people that some toxic additives to the fracking water could end up seeping into local groundwater, and ultimately into drinking water. That was the subject of a recent documentary film called GasLand.

Other highlights of the museum include a real Sputnik satellite – apparently the Soviets made lots of them, but didn’t get round to sending them into space – and a letter from Albert Einstein to Fort Worth schoolchildren that you can read below.

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Mural of the inner workings of the ATLAS detector by Josef Kristofoletti

By James Dacey

I’m on a bit of a comedown today after spending the past two days whizzing around CERN with a film crew to record a series of short videos for physicsworld.com.

It was my second time at the particle-physics lab and I was inspired yet again by the enthusiasm of researchers and the way they discuss profound questions of nature as if they were chatting about last night’s football or the weather.

My previous CERN visit was last March just after the Large Hadron Collider (LHC) had achieved its first collisions at 7 TeV and the physics programme was finally under way.

A year down the line and researchers across CERN’s various experiments have collected plenty of data to analyse and big physics results could be just around the corner.

One of our videos will look at the hunt for the Higgs boson and for physics beyond the Standard Model. We interviewed scientists from the LHC’s two general purpose detectors, CMS and ATLAS and both seemed fairly confident that they will have collected enough data by the end of 2012 (when the LHC will be shutdown for at least a year) to have a decent crack at finding the elusive Higgs. If indeed it exists!

Both scientists were also excited by the prospect of discovering SUSY particles to advance the theory of supersymmetry. This is the idea that every boson has a partner fermion with identical mass and internal quantum numbers.

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A separate video will look at the LHC’s ALICE experiment, which is designed to recreate the moments that existed just picoseconds after the Big Bang. I was particularly excited about this project because it meant I could interview my old university tutor, David Evans, who is head of the UK team at ALICE.

Evans was clearly really proud of his “girl” who apparently showed excellent performance recording data at the end of last year when the LHC collided lead ions instead of protons. The idea behind this is to create and study a state of matter known as quark-gluon plasma that may have existed at the very beginning of the universe.

But while news from CERN tends to be dominated these days by the LHC and its search for fundamental particles, there is plenty of other science going on there. Another video will look at one of these experiments, known as CLOUD, which is designed to study processes in the Earth’s atmosphere and the effect these could have on the climate.

Then in our final video we change direction again by exploring the CERN arts programme, which is seeing something of a renaissance under the leadership of Ariane Koek. Ariane, who has been employed to develop a cultural policy for CERN, explained to me that her big idea is to break down the barriers between art and science by creating opportunities for artists to come to CERN to collaborate with scientists.

All of these short films have now entered the post-production phase, but watch this space because they will be appearing on physicsworld.com over the next few weeks.

By Margaret Harris

Quick question: are time travel, invisibility cloaks and “tractor beams” that lift objects science fact, or science fiction?

I’d argue that all three are closer to science fact than science fiction. True, Britain’s streets are not lined with time-travelling Tardises (or is it Tardii?), but physical theories of the quantum vacuum indicate that subatomic particles are constantly popping back and forth in time. And although invisibility cloaks aren’t exactly at the Harry Potter stage, negative-refractive index materials are serious science – we’ve written several stories on them, including one just last week. As for tractor beams, the Bristol physicist Mervyn Miles may not be reeling in alien spacecraft, but this amazing video of his work shows that it’s perfectly possible to manipulate small objects with a laser beam.

However, according to this quiz on the BBC website, I’m wrong on two out of the three: time travel and invisibility cloaks are classed as “science fiction”, while Miles’s “tractor beams” are deemed “science fact”. Go figure.

The “news peg” for the quiz is a recent survey conducted by Birmingham Science City which purports to show that many Britons have trouble distinguishing between science fact and fiction. Reports on the survey have mostly heralded its results as proof of the British public’s ignorance, mocking the 30% of respondents who believed that time travel was possible and the 22% who thought that invisibility cloaks were the real deal.

But maybe the real story is that 70% and 78% thought – incorrectly – that they weren’t.

The flip-flop world of research

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By Louise Mayor

Life in research involves a turbulent rollercoaster of emotions. But often the only glimpse we see is the success and jubilation of when things work out and results get published.

This new video report (below) offers a behind-the-scenes look into the whole research process, from the long hours spent working in the lab to that day when the results finally get accepted for publication in a journal. It features researchers at Nottingham University achieving a breakthrough in part of their broader aim: to construct 3D objects on surfaces, atom by atom, using scanning probes. “The novel aspect of this video is not so much the science but the fact that we’ve filmed the entire research process over the course of a year or so,” says Philip Moriarty, the main protagonist in this adventure.

The joy that results when experiments go well comes across nicely when, while being filmed in the lab, Moriarty breaks off mid-sentence to throw his fists in the air and exclaim “yes!” However, he reveals that the groundwork preceding what looks so effortless has been 18-months-plus in the making and has sometimes involved 24- and even 36-hour shifts.

But research is rarely over once you’ve got that crucial result: there are then the highs and lows of trying to get the work published in as prestigious a journal as possible. Moriarty highlights that there’s a definite hierarchy of journals to which physicists submit papers. In this case their work was rejected from both Nature and Science before finally being accepted in Physical Review Letters.

Film-maker Brady Haran really digs deep with a frank set of questions that would make many less-composed subjects squirm, such as: “Why is this impressive?”; “What you’ve written…looks really hard to read and really boring – who’s this for?”; and “If only you and a select number of people in the world can understand that paper, how is it doing the world any good?”

The up-and-coming Haran highlights this video on his blog as a great example of what he hopes to achieve with science films. Haran is the mastermind behind the Test Tube project where this video is featured alongside a veritable trove of other gems, as well as The Periodic Table of Videos and Sixty Symbols.

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Dirac’s Drunkards in full flow (Courtesy: Caroline Prew)

By Michael Banks

It was a respectable/mediocre (delete as appropriate) result for the Physics World team at yesterday’s Big Science Pub Quiz held at Imperial College London.

The Physics World “dream team” – including myself, Matin Durrani, Margaret Harris and James Dacey – ventured down to London to test our general science knowledge in a quiz for journalists and academics, which was organized by the science PR office at Imperial.

A total of 16 teams entered from outlets such as Science (Professor Palin and the Fruit Flies), the Times (Meaty You’re Right), the Daily Mail (Imperial Storm Troopers) and Channel 4 (which must have had the team with the best name: Euclids on the Block).

Each team of journalists was put together with a team of academics from Imperial and we joined physicist John Tisch and four members of his quantum optics group for our team, which we called “Dirac’s Drunkards”.

After a few hairy questions in the true or false, science in the movies and picture rounds – for example, is it true that while babies have 300 bones, adults have only 206? – the half-time break couldn’t come quick enough, where we delved into (a rather bland) curry before getting on with the second half of the quiz, with a more taxing pot luck and music lyrics round.

In the end it was not meant to be for Dirac’s Drunkards. We shared eighth place with the BBC News Website (team-name: Denialists) with a score of 52.5 out of 95 – narrowly beating the BBC science radio unit (Radio Gaga) with 51 points and just missing out on seventh place from Euclids on the Block who managed 54 points.

To add further excitement to the night (as if that was at all needed), both teams from New Scientist were in the lead at the end of the quiz with a score of 66.5.

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So a tie-breaker question was needed and quiz master Gareth Mitchell asked one surely any particle physicist would know: what is the circumference of the Large Hadron Collider at CERN?

Indeed, it was the team that actually named itself after the collider (mischievously misspelling “Hadron” in Hadron Collider) who won, with a guess of 23 km while the Particle Zoo New Scientist team went for 50 km. Of course, as you will know, the answer is 27 km.

The picture on the right shows what the lucky winning team won, with each member taking home a Big Science Pub Quiz tankard.

Below are some example questions from yesterday’s quiz to see how you would have done (that is without using the internet/Wikipedia/Google of course).

Q) What element in the periodic table has the atomic number 36?
Q) Which Nobel laureate had the original name of Gábor Dénes?
Q) True or false? Women in Sweden have a lower body mass index than women in any other country in the European Union?

Answers on a postcard.

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By Margaret Harris

A couple weeks ago, the physicsworld.com blog brought you some of the sights and insights from the AAAS conference in Washington, DC. Today I’d like to bring you a few sounds as well, courtesy of Lelavision Physical Music, a dance-sculpture-music duo who formed part of the sonic backdrop to “Family Science Days” in the conference exhibit hall.

Lelavision were at the conference to perform a piece called “Accumulations of change”, which they had developed with David Lynn, an Emory University biochemist, as a way of representing the origins of life and evolution. During the actual performance, Lelavision dancer/gymnast Leah Mann was a little too busy balancing on a rotating DNA sculpture (see photo above left) to talk to me. Fortunately, I’d caught up with her earlier, when her sculptor/musician collaborator Ela Lamblin was laying down some patterns of sound to use in their performance. In the clip below, you’ll hear him in the background, making a “tink-tink” noise with the spheres shown in the photo above right.


Balancing act
An interview with Leah Mann.







And here’s what it sounded like when everything came together.


Patterns of sound
Ela Lamblin making molecular music.







On the role of snail slime

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By James Dacey

At first they may seem painfully slow and innocuous but give them an afternoon or so in your garden and they will have gobbled up your lilies before moving on to your prize-winning cabbages.

The way slugs and snails move around has captured the interest of researchers in Spain and the US, who are interested in how these slimy gastropods manage to effectively drag themselves through glue using just one foot.

Bioscientists already know that slugs and snails move by expanding and contracting their body in a series of muscular wave motions passing from the tail through to their head. What is less clear, however, is the role in locomotion played by the sticky mucus secreted from glands on the underside of the foot. This fluid is non-Newtonian, which basically means it does not deform in simple, predictable ways, like water for instance.

To investigate these slimy movements, Javier Rodríguez, a fluid dynamics researcher at the University of Carlos III in Madrid, working with colleagues at Stanford University and the University of California at San Diego, studied the gastropods in confined conditions. They captured a range images and other data of slugs and snails as they glided over transparent surfaces, which they then combined into 3D reconstructions.

To measure the speed of the body waves, for instance, they illuminated the snail’s foot from underneath using lights. Then to measure the vertical deformation of the body they shone a laser on the foot from a range of different angles (we’re informed it was a low-power laser so as not to harm the snails…)

Publishing their findings in the Journal of Experimental Biology, Rodríguez and co found is that the motion of slugs and snails has everything to do with the muscle movements of the slugs and snails and very little to do with the fact that the mucus is non-Newtonian.

Now, this may not sound like a particularly exciting result but it is good news for engineers who are trying to build robots that can drag themselves over surfaces in the same way as snails. The latest findings mean that machines could be rolled out in any old mucus and they would not need to fitted with personal supplies of special fluids.

One such idea, being proposed by a separate research group based in Japan, is to use the snail propulsion mechanism in biomedical applications to transport devices around the body. They envisage an endoscope being passed through the digestive system, taking advantage of the mucus film that lines the gastric tracts.

And if you have been left wondering why slugs and snails may have evolved to secrete complex non-Newtonian fluids, well it could be to serve other biological functions. “Without a doubt, it could have other uses, such as climbing walls, moving upside-down, or preserving moisture in the body when on a dry surface,” says Rodríguez.

By Hamish Johnston

Olivia Donovan of Halifax, Nova Scotia sent us a link to this video she made about how to make a diffusion cloud chamber from simple household items.

My favourite bit is when Olivia (age 15) demonstrates how to remove a radioactive piece of americium from a smoke detector. “Try not to point it directly at you,” she advises.

The americium provides the charged particles, which are detected in the chamber when they cause droplets to condense out of a super-saturated vapour of isopropyl alcohol. The chamber is cooled using an “air duster” – a can of compressed difluoroethane – and in the video Donovan shows how a few blasts of difluoroethane can cool a thermocouple to –45 °C.

It’s a lovely little experiment, and amazing to think that it can be done at home.

By Hamish Johnston

Imagine if you could reach out with your hands and grab a microscopic object – and watch as you move it about with micron precision or even spin it round. You could, for example, assemble a machine out of tiny components or poke and probe a bacterium or two.

Well, now all you need is an iPad – and a connection to a holographic optical tweezers system – thanks to a new software application created by researchers at the University of Glasgow and University of Bristol.

Holographic optical tweezers use a spatial light modulator to split and steer a laser beam so that it can be used to manipulate multiple microscopic objects in 3D.

The challenge, however, is how to interface such an instrument with a human operator.

In December I saw a fantastic lecture by Mervyn Miles of the University of Bristol that offered one solution – a custom-built “multi-touch table” with a screen that displays a live microscope image from holographic optical tweezers. If you pinch your fingers round a micron-sized glass ball, you can grab it with the tweezers and move it to another location.

Now Miles and colleagues have transferred this technology to an Apple iPad – perhaps not the cheapest electronic gadget, but much less expensive than their bespoke table.

You can watch a demonstration in the above video and read all about the iPad app in this paper in the Journal of Optics.

Four steps to success

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By Louise Mayor

Today CERN announced on its Twitter feed that “the first 7 TeV LHC [proton] collisions of 2011 were recorded last night, round midnight, with low intensity beams”.

But how do particle physicists work out from the millions of detected collision events per day whether they are observing a new particle or phenomenon?

Tommaso Dorigo, a collaborator on the Compact Muon Solenoid collaboration at CERN and the Collider Detector at Fermilab, has described just what researchers are looking for and how they go about their search in a fabulous new article, “On the road to discovery”, in the March 2011 issue of Physics World. You can read it here.

In his article Dorigo breaks down the search for new physics into four general steps and to make this clear he sent us these four charming hand-drawn sketches (below).

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In the sketches, Dorigo imagines looking for a particle that theory says will decay to a pair of particle jets which fly out back-to-back. But before even looking for new physics, the detector must first be checked – does it do everything we expect for particles and phenomena that we do know about already? That’s step 1.

Now we’re ready to take on the maelstrom of data – huge files where as much as possible about each collision has been recorded. To make a detailed analysis of every single file would take ridiculous amounts of computer power, so step 2 involves culling anything that’s obviously not what we’re looking for. Here we’re looking for two jets back-to-back, so anything else – no jets, three jets, or two jets not back-to-back – is scrapped.

In step 3, the remaining events are split into either “background” or “signal”, and the background events – those we already understand with the Standard Model – are discarded. These are in effect considered to be background noise, and the aim is to remove this so that any signal is easier to spot.

Events are classed as “background” if the particles produced are only at a small angle to the beam so have not undergone much momentum change – you can imagine these events to be like a truck that hits a stray goose and does not go far off course, as opposed to a head-on truck-on-truck crash where debris might fly off sideways.

In the fourth and final step, the mass of the jet pairs is plotted on a histogram along with all the other events analysed so far. The shape of this distribution is compared to the “null” hypothesis – the shape if the particle being searched for doesn’t exist – and the “alternate” hypothesis – the shape if the particle does exist. Statistics are used to say how confidently the data agrees with the new idea – usually converted into units of “standard deviations”.

You can read more about this in Dorigo’s feature article: On the road to discovery.

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By Hamish Johnston

About 13.7 billion years is the best estimate for the age of the universe, but how did scientists reach this conclusion and what twists and turns were encountered along the way?

That was the question that the BBC’s Melvyn Bragg put to three astronomers this morning on his radio programme In Our Time. Bragg’s guests were Martin Rees – Britain’s Astronomer Royal – Carolin Crawford of the University of Cambridge and Carlos Frenk of the University of Durham.

Bragg begins with James Ussher’s pronouncement of 1654 that the Earth was formed at 6 p.m. on 22 October 4004 BC. Ussher (right) was Archbishop of Armagh and this date was the result of painstaking historical and biblical research.

This Old Testament view of creation endured until the 19th century, when geological evidence and the new theory of evolution suggested that the Earth was at least hundreds of millions of years old – a figure championed by none other than Charles Darwin.

At first, however, evidence from the heavens seemed to contradict earthbound data. Indeed Lord Kelvin calculated that the Sun was at most a few million years old. His argument – which assumed that our star is heated by gravitational energy – was so persuasive that it made Darwin doubt his geological and evolutionary observations.

The discovery of radioactive fission muddied the waters even more. On one hand it suggested that the Earth was as much as three billion years old, but it could not ascribe a similar longevity to the Sun. Eventually, estimates for the ages of the Earth, Sun and the universe fell into line thanks to the work of astronomers, astrophysicists and cosmologists.

To hear more details of the various theories about the age of the universe – including Newton’s rather elegant proof that the cosmos is at equilibrium and therefore ageless – listen to Bragg’s programme here.

The art of physics demonstrations

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By James Dacey

Never underestimate the power of a good science demonstration. Some of the most celebrated science communicators like Richard Feynman and Carl Sagan, and more recently Brian Cox, are incredibly good at explaining academic research using simple, everyday concepts. But while a few lucky people seem to be naturally good at coming up with nifty demonstrations, most educators could always pick up some tips from the professionals.

I recently went along to the conference of the Association for Science Education to make a couple of short films about how practical demonstrations can breathe new life into physics education. The ASE is a UK-based organization that has been supporting teachers and science educators since 1900, and it now attracts around 3000 delegates to its annual conference, which was hosted this year by the University of Reading.

In the first video I present an overview of the conference, focusing on the best physics demonstrations delivered by a number of specialist educators. Some of the demos are very flashy, but they are all designed to be simple enough for teachers to recreate in their classrooms without forking out heaps of cash on specialist gear. My personal favourite was the helical flames that seemed to lick the classroom ceiling, drawing gasps from the audience.

In the second of these videos you can see me take part in a special workshop for teachers where we were taught how to make mini dragster cars and how we can use these vehicles to communicate physics principles like aerodynamics and friction. The session turned out to be a really good laugh and it was useful to brush up on my basic physics. Though, needless to say, I left most of the serious mechanics to the real experts – the teachers.

For me, the take-home message of the conference is summed up very eloquently by one of the demonstrators, Gary Williams, who is editor of the journal Physics Education. “It’s all very well doing theory, but until you’ve interfered with the universe, actually done something, stretched it, pulled it a little bit, then you don’t really know how it reacts. Practical is crucial to science.”

You can also see full versions of a selection of the physics demonstrations from the ASE conference on the Physics Education Youtube channel.