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Why chemistry labs need expert glassblowers

By Oli Usher, on 11 September 2015

flask

Chemistry labs need skilled glassblowers to produce some of the intricate, bespoke glassware for some of their experiments. This item, produced by one of UCL’s glassblowers, is designed to be placed on a heat source so it can distill liquids and deposit them in ampoules along its long stem.

The flask’s design includes bell-shaped edges inside to encourage the liquid to evaporate evenly. The gas then cools and condenses inside the long stem, collecting at the end. When enough has collected there, the end of the stem can be melted off, sealing the liquid safely inside.

Ferrocene crystals

By Oli Usher, on 10 June 2015

Ferrocene

Ferrocene. Credit: Prof Andrea Sella

These two images show crystals grown by 2nd year undergraduates in UCL’s chemistry department, as part of their practical classes this week.

The orange grains in the image above are crystals of ferrocene; the darker granules below are made up of the related substance ferrocenium hexafluorophosphate (also known as ferrocenium FP6)

Ferrocenium PF6

Ferrocenium PF6. Credit: Prof Andrea Sella

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Darkness falls across the land

By Dewi W Lewis, on 24 March 2015

 

eclipse

These two photographs were taken in the quad during the eclipse. The first at 9:25 the second at 9:31am.

During this time the light dropped by a factor of 16: dropping from an Exposure Value (EV) value of 11 to 7, or 4 stops, to the photographers amongst you.

My eyes told me it got “a bit darker”, the reality was far more!

Hydrophobic art

By Oli Usher, on 5 March 2015

paint

Yau Lu (UCL Chemistry) is the lead author of some research which hit the headlines last week. His team has succeeded in making a water-resistant and self-cleaning coating which is both highly effective and very strong. Previous coatings have been weak, and easily scratched or flaked off.

Here, he shows how the hydrophobic  paint can be used to create a water-repellent design on glass. The hydrophobic coating, water and dye all come together to create an ephemeral artwork:

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Where noble gases won UCL a Nobel Prize

By Oli Usher, on 2 March 2015

IMG_0073-cc

Readers familiar with UCL will immediately recognise the Slade School of Fine Art – the North Wing on UCL’s historic (and grade I listed) quadrangle. What they may not know is that the building, which dates back to the 1870s, was originally also home to UCL’s Department of Chemistry.

It was in this building that some of UCL’s most famous contributions to chemistry were made: William Ramsay and his successor J Norman Collie both worked here.

In fact, as far as we can work out, it is the building in the world which has seen the discovery of the greatest number of chemical elements. Ramsay discovered argon, neon, krypton and xenon while working here, as well as isolating helium (which had been seen in the spectrum of the Sun, but not observed here on Earth) and radon. These elements are together known as the noble gases, and Ramsay’s discoveries secured for him the 1904 Nobel Prize in Chemistry – UCL’s first.

In 1913, the year of Ramsay’s retirement, UCL’s Chemistry department moved to a new purpose-built lab immediately behind its old home. The building – which still houses some of the department’s laboratories and offices – is now named after another towering figure in chemistry: Kathleen Lonsdale.

After a century of heavy use and piecemeal remodelling, the building is looking a little tired . A multi-million pound complete refurbishment of the building is planned to begin later this year.

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Charged with uncertainty: how a classic classroom experiment reveals what we don’t know about static electricity

By Oli Usher, on 20 November 2014

Rub a balloon or a plastic rod, charging it up with static electricity, and it can suddenly pick up little pieces of paper. It’s a common classroom demonstration in high school science classes, an everyday example of electrostatic attraction. But it’s never explained fully in class – pupils are told about plastics gaining or losing electrons and becoming charged, but why (and how) this charge is actually created is never explained.

Static electricity picking up scraps of paper. Photo: Tess Watson (CC BY)

Static electricity picking up scraps of paper. Photo: Tess Watson (CC BY)

The reason for this is as simple as it is surprising: nobody actually knows.

***

Much of what we are taught in school science lessons is wrong. Electrons are not billiard balls spinning around an atomic nucleus – even if that’s a useful metaphor. Newton’s laws do not govern the motion of objects – though in most cases, they are so close as makes no difference. Copernicus did not claim, let alone prove, that the Earth orbits the Sun, though his model of the cosmos was an important innovation in the history of astronomy.

In all these cases, the classroom version is a reasonable approximation, a simplification which still helps children learn about science, without getting bogged down in unnecessary complexity.

But in the case of plastic being charged up with static electricity, scientists genuinely don’t fully understand what’s going on.

***

Katherine Holt

Katherine Holt

Katherine Holt is a researcher in UCL Chemistry who has worked on electrostatic charging, and is hoping to answer some of these questions. Initially interested in the way that charge can build up on the surfaces of nanodiamonds (microscopic diamonds formed in the soot created by explosives), she has come to work on the question of how static electricity forms on the surfaces of plastics.

For many years, this was the preserve of physicists, who looked at the big picture of how charge behaves on the surface of a whole object. But with the improvement in tools such as magnetic force microscopes, the field has in recent years opened up to chemists, who are interested in small-scale properties of materials, such as bonds between atoms, breaking and joining of atoms in molecules, the microscopic structure of surfaces and the behaviour of individual ions and electrons.

This change of emphasis, Holt says, has brought about a growing conviction that even the most superficial explanation given in school (“electrons are transferred to or from the plastic when it is rubbed”) is wrong. It is increasingly clear that the charging process is actually linked to imperceptible damage to the surface. Bonds between atoms on the plastic’s surface are being broken by the rubbing and this – not the exchange of electrons between surfaces – is leading to the charge being created.

Tunneling electron microscope image of two polystyrene beads rubbing together and then separating that clearly shows that material is transfered from one surface to another as they do so and that the surfaces become 'scarred' and damaged. Credit: Katherine Holt (UCL Chemistry)

Tunneling electron microscope image of two polystyrene beads rubbing together and then separating that clearly shows that material is transfered from one surface to another as they do so and that the surfaces become ‘scarred’ and damaged. Credit: Katherine Holt (UCL Chemistry)

But identifying microscopic damage on the surface and linking that to the creation of static electricity isn’t the same as figuring out what is actually going on.

***

When you break bonds between atoms in molecules, shattered fragments of those molecules (either individual atoms or groups of atoms) are formed. These highly reactive particles are known as free radicals.

And indeed, Holt says, you can find free radicals on the surface of charged plastic rods. What’s more, in the same location as these radicals, surface imaging techniques reveal the presence of electric charge.

But even this still doesn’t solve the mystery of precisely how electrostatic charging works: radicals are electrically neutral, so some other particle – presumably ions or electrons – must be carrying the charge.

There is more that isn’t known.

For instance, whether a plastic will become positively or negatively charged is easily predicted, there is even a table (the triboelectric series) which sets out which combinations of common polymers will charge each other positively or negatively when rubbed against each other. But the triboelectric series is based on experimental data – there is no underlying theory explaining what is actually going on, and Holt says, there may never be one: there could be a diverse range of different phenomena all contributing to the different electrostatic properties of the different plastics.

***

Working in a field which is experimentally well understood, but lacking in theoretical explanation, is not an entirely comfortable area for scientists. For engineers, however, who are interested in practical applications and less worried about theory, this is far more usual territory.

Holt says that, despite being a chemist, she’s now finding it easier to talk to engineers about her work in this area than she does with colleagues in closely aligned fields of chemistry. Engineers are interested in electrostatic charging for prosaic reasons – preventing powders from clumping together in factories, for example – and have an extensive practical understanding of it. But they don’t care in what’s happening on a molecular level.

Which, when the underlying science is as intractable as this, seems like quite a tempting thing to do.

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Representing resource use at UCL… using chemistry glassware and electronics

By Kat F Austen, on 20 October 2014

Elements

Elements

How do you represent the complexities of the resource use of a university using just what you can find in a chemistry lab – and some collective ingenuity?

That’s what Andrea Sella, Joanna Marshall-Cook and I set out to do over the course of last week with the help of Rae Harbird and Stephen Hailes.

The result, Elements, is on show in UCL’s North Cloisters for Degrees of Change, a week long endeavour by UCL’s Sustainability team to explore the environmental consequences of all the world-class teaching, research, collecting, exhibiting, making, inventing and outreach that goes on at the university.

During the research for the installation I learned some interesting statistics. For instance, a typical chemistry fume cupboard uses 10,000kWh of electricity per year (£1,000), and our heating comes from a series of underground pipes.

The installation is a visual metaphor for how the university’s heating and water systems work. We often don’t think about the consequences of running a tap, or pouring a bucket down a drain, flushing a toilet, taking a shower. Chemical glassware in all its varied and complex forms provides a perfect toolbox to explore the convoluted system of flows in resource infrastructure. Elements incorporates soxhlets – a type of chemical glassware normally used for extracting liquid from a solid, such as producing essential oils – which act as reservoirs within the system as a whole, just as we act as reservoirs for water either within ourselves or by our actions.

Lots of crazy glassware and - lit up in green and looking suspiciously like UCL Engineering's logo, an EngDuino computer, monitoring the water level in the system

Lots of crazy glassware and – lit up in green and looking suspiciously like UCL Engineering’s logo – an EngDuino computer, monitoring the water level in the system

The crazy glassware installation also has a 5L round bottomed flask and an electric pump – after all, it takes power to heat and move all the university’s water. The flask is like the water infrastructure external to UCL – and is monitored by an EngDuino and sensor, programmed by Rae and Stephen, that alerts us when the water levels are low.

A sensor detects the water level and reports back to the Engduino if the level is too low

A sensor detects the water level and reports back to the Engduino if the level is too low

At a time of increasing water scarcity and climate change due to our energy use, it’s important to realise that our actions on a personal scale have a real affect that ripples through the infrastructure that helps us live as well as we do.

UCL’s first Nobel Prize

By Oli Usher, on 7 October 2014

William Ramsay's Nobel Prize

William Ramsay’s Nobel Prize certificate. Photo: public domain

This week is Nobel Prize week. Prof John O’Keefe (UCL Cell & Developmental Biology) has just been announced as the winner of the 2014 Physiology or Medicine Nobel Prize for his work on positioning systems in the brain.

He joins a long list of Nobel laureates affiliated to UCL.

The very first of these was Sir William Ramsay, who won the 1904 Nobel Prize in Chemistry. Ramsay is seen as one of the fathers of chemistry at UCL, and he is responsible for the discovery of the noble gases. He also supervised two students who also went on to win Nobel Prizes themselves: Jaroslav Heyrovský and Otto Hahn.

Ramsay’s Nobel Prize certificate, pictured above, is held in UCL’s collections, along with his medal and some of the apparatus he used to carry out his research.

Links

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Kathleen Lonsdale interview

By Oli Usher, on 19 August 2014

If you don’t know who Kathleen Lonsdale was, you should.

Lonsdale was a hugely important chemist (in the field of crystallography), an outspoken political activist and president of what is now the British Science Association. She was also, from 1949, the first woman to become a professor at UCL.

BBC Woman’s Hour interviewed her in 1967, shortly before she retired from UCL. The programme, available on iPlayer, is well worth a listen.



Lonsdale retired from UCL in 1968, and died in 1971, but she is commemorated in the name of the Kathleen Lonsdale Building on Gower Place. This building houses many of UCL’s science labs.

Lonsdale is remembered in the name of the Kathleen Lonsdale Building, which houses many of UCL's science labs. Photo: Gnesener1900 (CC-BY-SA)

Lonsdale is remembered in the name of the Kathleen Lonsdale Building, which houses many of UCL’s science labs. Photo: Gnesener1900CC-BY-SA

Thanks to Joe Cain for bringing this to our attention.

Picture of the week: Release valve

By Oli Usher, on 7 July 2014

Semiconductors are the basis of almost all the electronics we are used to today. Transistors are tiny switches (often microscopic) which govern how electricity flows through a device, thanks to their variable electrical conductivity. Putting many transistors in sequence means the flow of electrons through the circuit can begin to follow logical rules and make calculations – the basis of all computing. Even small devices like smartphones can today contain over a billion transistors squeezed onto the tiny chips inside them.

But electronics existed before semiconductors. The transistor was invented in the late 1940s, and only became widely used in the mid 1950s, a decade after the invention of electronic computers.

Early electronic devices, including the first computers such as Colossus and ENIAC, relied instead on thermionic valves.

Mullard electronic valve

A small electronic valve manufactured by Mullard. (This is the same Mullard that endowed UCL’s Mullard Space Science Laboratory). Photo: O. Usher (UCL MAPS)

Dating back to the early 20th century, valves can carry out the same functions as semiconductors do today, acting as switches and diodes. But the principles they work on are totally different – instead of exploiting the quantum properties of semiconductors, valves use brute force: glowing hot filaments that flood the valve with electrons.

This means they are extremely energy-inefficient – the ENIAC computer, with just under 18,000 valves (compare this to over a billion transistors in an iPhone) drew 150 kilowatts of power. A typical oven uses around 2 kW, a modern laptop computer uses less than 0.1 kW.

This high power consumption also means that valves look a lot like another device with a glowing filament, appalling energy efficiency and vast production of waste heat: the filament light bulb. (Like old-style light bulbs, valves also regularly burn out and need to be replaced.)

A selection of thermionic valves found in UCL Chemistry

A selection of larger thermionic valves found in UCL Chemistry. Photo: O. Usher (UCL MAPS)

Valves were widely used for electronic applications in university labs until their relatively sudden obsolescence in the 1950s left unused stocks in store rooms. They still occasionally turn up when cupboards are cleared out – including a large haul of several crates of mint-condition valves recently found in UCL’s Department of Chemistry, pictured here. These are of little use for research today, but they are of great historical interest, not least for restoring and repairing old electronic devices.

Dekatrons (counting tubes), widely used in early computers including the Harwell Dekatron Computer, which is now at the National Museum of Computing.

Dekatrons (counting tubes) were widely used in early computers including the Harwell Dekatron Computer, which is now at the National Museum of Computing.

For this reason, the valves have been donated to the National Museum of Computing at Bletchley Park.