Category Archives: Physics

Science on the telly

The Science Museum is formally over 100 years old.

The Science Museum's permanent building under construction, 1916 (Science Museum / Science & Society)

Over the century since 1909, it has had to compete with more and more media getting-in on the business of popular science.

A hundred years ago, popular science publishing was already a big scene, as Peter Bowler shows in his enlightening new book, Science for All.

Radio came along in the 1930s, and soon featured science. But our biggest competitor really got into its stride in the 1950s, when television began to get seriously interested, long before even Tomorrow’s World .

BBC producers had heated arguments about whether to treat science in highly-crafted documentaries, or as topical live programmes in the studio or out in the scientists’ labs.

Very often, the same subjects have been treated in books, radio, television and the Museum. Sometimes the same people crop up on television, in Museum displays, and also behind the scenes. One example is Lawrence Bragg, the distinguished physicist.

Bragg served on the BBC’s General Advisory Council, where he worked hard to promote the cause of science broadcasts. He was also on the Science Museum’s Advisory Council in the ’60s. His Royal Institution Lectures were the first to be broadcast live in 1959. There is a rare opportunity to see him in action, in Before Horizon, a special showing at BFI Southbank on Monday 7th June. Why not make a day of it and spend the afternoon at the Science Museum?

Our displays include at the X-ray spectrometer used by Lawrence and his father William in our Making the Modern World gallery.

Sound Advice

I set out to the National Physical Laboratory the other day and on my way down Exhibition Road passed an elephant.

Elephant Family appeal, Exhibition Road

Elephant Family appeal, Exhibition Road, 2010 (Doug Millard)

Some 250 of these colourful models are being positioned across London to raise awareness and funds for the plight of their living cousins. A little later something niggled at the back of my mind – as though that elephant was trying to tell me something – but I thought no more of it and caught a train for Teddington and the NPL.

This, I’m ashamed to say, was my first visit to the Laboratory, also known as the National Measurement Institute, where, for over a century, physical standards have been measured, studied, applied or all three.

Scientists at the NPL, 1932

Scientists at the NPL, 1932 (Science Museum/Science & Society)

It was International Metrology Day, May 20th - exactly 135 years since seventeen nations agreed to the metre as the fundamental unit of length. The original Metre, made from platinum and iridium, is housed in Paris but the NPL has one of the carefully guarded official copies. These days a Metre is defined by the distance light travels in a vacuum during 1/299 792 458 of a second.

NPL also does a lot on sound - acoustics - and I was particularly impressed by the Laboratory’s anechoic chambers.

Science of Acoustics, 1850

Science of Acoustics, 1850 (Science Museum/Science & Society)

Now, while the Science Museum has all sorts of acoustics objects and pictures in its collections it has nothing like the NPL’s rather fearsome looking chambers where sounds produce no echo; here’s a link to one of the NPL’s anechoic chambers in action.

NPL Anechoic Chamber, 2010

NPL Anechoic Chamber, 2010 (Crown)

The NPL studies all manner of sounds, those the human ear can readily detect but also those at too high a frequency for us to hear – ultrasonic – or too low – infrasonic. Other animals are different, though: elephants, for example, have been shown to communicate using really low frequencies. Scientists suggest that this allows them to coordinate their own movements over distances of many kilometres. Maybe the Exhibition Road elephant was trying to tell me something earlier that day.

Light fantastic

Fifty years ago yesterday, Theodore Maiman demonstrated the first working laser. At the time, there didn’t seem an obvious use for the technology (although several newspapers ran fanciful stories about ‘death rays’) and it was dubbed ‘a solution looking for a problem‘. Five decades on, lasers are so widespread that we barely notice our everyday encounters with them at the office printer, the supermarket barcode scanner, or the DVD player at home.

DVDs are written and read by laser. (Science Museum)

The basic principle of a laser is pumping energy into a medium to excite its atoms so that they emit photons of light, then amplifying and aligning this emission. The first lasers used ruby rods as the medium – here‘s an explanation of how a ruby laser works.

The chamber of this early laser is opened so that you can see the ruby rod. (Science Museum)

Since then a huge variety of materials has been used in lasers including gold, organic dyes, semiconductors, and gases like helium-neon (the common red laser) and carbon dioxide, widely used for industrial cutting and welding. Or, more weirdly, lasers have even been made from jelly!

The world's first Transversely Excited Atmospheric laser, built at Baldock in 1974, uses a cylinder of carbon dioxide as the medium. (Science Museum)

As well as the now-familiar everyday uses, lasers are increasingly used in medicine. Laser guide stars have helped sharpen the view of major telescopes. Laser weaponry is moving out of the world of James Bond and into reality. One day, lasers might even be used for fusion, providing us with plentiful clean energy. For a more detailed take on the laser’s fascinating history and promising future, check out the special anniversary edition of Physics World. Here’s to the next fifty years.

Shrouded in mystery

The Shroud of Turin is on public display for the first time in a decade. The Pope paid a visit  on Sunday and over two million people are expected to queue up to see the shroud during a six-week showing in Turin Cathedral. Some people will be there because they believe the shroud is the burial cloth of Christ, others will be sceptics wanting a closer look at what has widely been dismissed as a medieval forgery.

This small container carried a small sample of the shroud to Oxford for testing. (Science Museum)

A strong case against the shroud’s authenticity was made in 1998, when samples were radiocarbon-dated by three independent laboratories. This container in our nuclear physics collection was used to transport the sample that went to the University of Oxford’s Radiocarbon Accelerator Unit - the red wax is the Archbishop of Turin’s seal confirming that the sample came from the shroud. The Oxford experiments concluded that the sample was around 750 years old, in broad agreement with the results from the other laboratories.

Seemingly conclusive evidence that the shroud is from the Middle Ages and not the time of Christ. But some people have argued that there may be other explanations, for example the shroud being contaminated during centuries of storage, or the samples having been taken from a medieval repair patch on a much older artefact.

Further testing may help to pin down the age of the fabric, although so far the Catholic Church has been reluctant to expose this iconic artefact to further study. And an agreed age still wouldn’t explain how the image of the man was formed – and certainly not who that man was. During his visit the Pope was careful to remain non-committal on the question of the shroud’s authenticity. It looks like this controversial item will remain a scientific as well as a religious mystery for a while longer.

Hitting the accelerator

Science Museum curators seem to have a curious affinity for tunnels. Stewart’s been down a sewer, David ventured under the Thames, and I’ve just been to one of the biggest tunnels in the world, a 27km ring under Switzerland and France. Yes, it’s the Large Hadron Collider at CERN. Unlike my colleagues I didn’t get to enter this tunnel – that would be a bit inconvenient right now, as on Tuesday the LHC commenced physics operations, colliding beams of protons at the highest energies ever achieved by a particle accelerator.

Hitting the headlines: 'a first big bang rocks Geneva'. (Alison Boyle)

I was visiting CERN as part of our physics collecting project, to see what artefacts they might be able to spare for the Science Museum. Like us, they are wrestling with how to preserve Big Science. I had a fascinating tour around the magnet lab – these ones were damaged in the 2008 accident that temporarily halted the LHC, and are being repaired.

Magnets under repair (Alison Boyle)

Before I left, I had a splurge in CERN’s gift shop. As well as serious science kit, we like to collect ephemera showing popular reactions to science. This natty bag features part of the mathematical equation predicting the existence of the Higgs Boson, which the LHC’s ATLAS experiment aims to detect. This jigsaw looks almost as complicated to build as ATLAS itself!

Scientific souvenirs (Alison Boyle)

A great thing about visiting places like CERN is that you hear some interesting anecdotes. It turns out there’s a reason why the LHC’s dipole magnets are clad in blue piping.

LHC magnets in an enclosure showing how big the tunnel is. (Alison Boyle)

CERN’s Director General during LHC planning was Chris Llewellyn Smith. Asked what colour to make the pipes, he opted for the colours of Oxford University, where he was a professor. I wonder if a link to the world’s highest-energy accelerator will give Oxford the edge over Cambridge in this Saturday’s Boat Race?

A grand day out at RAL

My favourite part of curatorial work is adding new objects to the collections. Aside from the warm fuzzy glow of knowing that something I’ve acquired will be stumbled upon by future generations of curators, visitors and researchers, it’s always an opportunity to find out something new and meet interesting people. 

Recently, I visited the Rutherford Appleton Laboratory for a whistle-stop tour. As I’ve mentioned before, I’m working on a project to bring our physics collections up to date, and RAL is a great place to start. RAL’s scientists and engineers are involved in projects worldwide, and the on-site facilities are used for a huge range of applications, from studying photosynthesis to analysing timbers from the Mary Rose

First stop was the giant Vulcan laser, one of the world’s most powerful. The whole thing is too big to photograph but you can take a virtual tour here

Keeping an eye on things in Vulcan's control room (Credit: Alison Boyle)

Then on to the Diamond Light Source. This is a synchrotron, accelerating electrons to generate high-intensity light for use in experiments. This animation explains how it works. Diamond’s electron storage ring is more than 500m around – here’s a bit of it. 

This photo was taken standing on top of Diamond's electron storage ring, the white structure curving off in the distance. The light beams are directed to experiment rooms inside the yellow structures. Credit: Alison Boyle

Next stop was the Particle Physics Department, finding out about RAL’s involvement in the Large Hadron Collider’s CMS experiment. More about the LHC in a few weeks, as I’m off to CERN shortly. 

And finally on to ISIS, an accelerator which generates pulses of neutrons and muons to explore materials in detail. ISIS is even bigger than Diamond – here’s part of one of the halls. 

Inside one of the ISIS target halls. Protons are accelerated through the white structure and slam into a target inside the blue structure, generating muons and neutrons for experiments. Credit: Alison Boyle.

During the tour, my magpie-like curator’s eye noticed a few bits and pieces of interest to the museum, so if I can persuade their owners to part with them, you may be seeing them in our collections soon.  Thanks to Katy, Graeme, Cristina, Laura, Jen, Bruce and Chris for a great day!

Up and atom

If you’re planning to attend Monday’s Centenary talk on the Large Hadron Collider, you can spot a few of its distant ancestors as you pass through the Making the Modern World gallery en route to hear Brian Cox speak.

Looming large on the left of the central walkway is the cascade generator from John Cockcroft and Ernest Walton’s million-volt accelerator. This generated 1.25 million volts to accelerate protons and smash them into atomic nuclei, breaking the nuclei apart. During the Second World War this apparatus was used to study uranium and plutonium, contributing to the Manhattan Project.

Detail of the cascade generator (Image: Science Museum)

Detail of the cascade generator (Image: Science Museum)

The million-volt accelerator is a souped-up version of the appartus that Cockcroft and Walton used to split the atom in 1932, the first time this had been done in a controlled situation. This work, which earned them a Nobel Prize, provided the first experimental proof of Einstein’s famous equation, E=mc2. You can see this accelerator in miniature on the gallery’s model walkway (parts of the real thing are at our Wroughton store).

Model of Cockcroft and Waltons laboratory - spot the scientist in the shielded cabin to the right. (Image: Science Museum)

Model of Cockcroft and Walton's laboratory - spot the scientist in the shielded cabin to the right. (Image: Science Museum)

As you can tell from the size of the person in the model, this equipment was large and unweildy. Meanwhile in America, Ernest Lawrence and his student M. Stanley Livingston had been working on ways of repeatedly passing particles through the same accelerating voltage, to get a bigger overall effect. Lawrence proposed using magnets to whirl charged particles around in an ever-increasing spiral, so that they could keep crossing the same voltage gap  (his patent diagram helps explain it). The cyclotron, as the device came to be known, could split atoms in equipment that fitted on a laboratory bench.

In 1931, Livingston passed the magic million-volt mark with an 11-inch cyclotron, which prompted an excited telegram from the lab to Lawrence: “Dr Livingston has asked me to advise you that he has obtained 1,100,000 volt protons. He also suggsted that I add ‘Whoopee!”.  You can see an early example of this whoopee-inducing device in the bench case opposite Cockcroft and Walton’s cascade generator. Shortly after Cockcroft and Walton, Lawrence also succeeded in splitting the atom, and the invention of the cyclotron earned him a Nobel gong too.

Early cyclotron designed by Lawrence, 1932

Early 11-inch cyclotron designed by Lawrence, 1932

These early atom-splitters ushered in the age of Big Science, with particle accelerators getting bigger and bigger as physicists continued their quest to probe ever-higher energies. And as I’ve mentioned previously, the Large Hadron Collider is the biggest of big. Hope you enjoy the big ideas in Professor Cox’s talk!

This blog has gravity

Picture the scene. Two men are lurking at a London station, waiting for the Glasgow train. The train arrives and a third man disembarks, wheeling a suitcase. The three exchange some quick words of identification, the Londoners give the man from Glasgow an envelope of papers and he hands over the suitcase. The Londoners jump into a taxi with the suitcase … which contains a 23kg sapphire.

No, it’s not a scene from the latest Bond movie. The man on the Glasgow train was astronomer Martin Hendry and the others were my colleagues Doug and Chris. Martin’s department loaned us the sapphire for display, and rather than send our van the whole way to Glasgow and back we kept our carbon footprint down by arranging to  meet when Martin had to be in London anyway. Martin was back in London last weekend, and here he is with the sapphire in the Cosmos & Culture gallery.

Martin checks were taking care of his sapphire

Martin checks we're taking care of his sapphire

‘What sapphire?’ you might ask. If you were expecting something blue and multifaceted, look again. It’s the round clear object on the front shelf. It’s pure synthetic sapphire and it’s a test mass for an experiment called GEO600, which is using laser beams to try and detect gravitational waves, tiny ripples in space-time predicted by Einstein. To find out more about these types of experiment work, check out this video on our YouTube channel

Martin joined us to give a talk as part of our Cosmic Explorers Day event, which was supported by the Royal Astronomical Society as part of the International Year of Astronomy 2009 celebrations.  The day looked at how we make sense of space (or try to) and the enduring influence of Albert Einstein. But Einstein’s influence has spread far beyond astronomy – here’s a fun example from our collections.

An unusual use of Einsteins image (Credit: Science Museum)

An unusual use of Einstein's image (Credit: Science Museum)

Why use an image of a German-Swiss-American theoretical physicist to sell an Australian shoe spray?  Well, Einstein did have sweaty feet (which, along with varicose veins, got him out of doing Swiss national service) and famously never wore socks, but the packaging makes no reference to this. The famous image of the white-haired scientist seems to have been used to reinforce the makers’ claim that the spray is ‘scientifically proven’ to eliminate shoe odours, showing how Einstein has become the face of science for many. Martin evidently approves – look at his Tshirt – although we are sure he has very fragrant feet!

Smashing machines

After over a year of delays, the Large Hadron Collider at CERN has smashed its first particles together. The accelerator is due to commence full operation in the next few weeks (assuming it doesn’t get sabotaged from the future … or baffled by a baguette).

Particles in the LHC travel at almost light speed, guided by superconducting magnets. They travel inside a beam screen, kept at a temperature of 5 degrees Kelvin (-268 Celsius), which shield the magnets from the intense particle beam.  Here’s our section cut from a spare beam screen.

Section of a beam screen from the Large Hadron Collider, 2001 (Credit: Science Museum)

Section of a beam screen from the Large Hadron Collider, 2001 (Credit: Science Museum)

Today’s particle physics poses a curatorial challenge, not least because Big Science is getting bigger. A few years ago we collected the Central Tracking Detector from ZEUS, a UK built-experiment which ran in Germany’s HERA electron-proton collider from 1992-2007. (As you can imagine from that last sentence, another challenge is remembering what all the acronyms stand for.) The photograph below shows the CTD being unloaded at Wroughton. It’s a pretty hefty beast but was only a small part of the whole ZEUS apparatus, which weighed in at 3600 tons.

Central Tracking Detector being unloaded at Science Museum Swindon, 2008

Central Tracking Detector being unloaded at Science Museum Swindon, 2008

Techniques learned in building and operating ZEUS helped in the design and construction of the LHC’s ATLAS experiment, the biggest and most complex particle detector ever built. ATLAS is 45m long and weighs as much as the Eiffel Tower. In trying to preserve some record of it in our collections, we need to consider the implications of an experiment that dwarfs any of our galleries – how much of it would be enough to be meaningful in its own right? What do we do about the vast networks of cables and computers for sorting and analysing the data? And then there’s the small matter of getting large chunks of kit out of the LHC ring and back to the museum.

We don’t have all the answers, but it’s something I’ll be thinking about a lot over the next few months as we’re actively adding to our physics collections. Watch out for future blogs on the subject. And in the meantime, why not book yourself a seat at our Centenary Talk with Professor Brian Cox on 18 January, where you can find out more about what’s going on at the LHC.