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Student Supplement

Issue 107 november 2007

Issue 107 november 2007

NOVEMBER 2007 • VOLUME 44 • NUMBER 6

In-fl ight polymersUsing plastics will save fuel

Hydrogen storageFuel cell-powered cars – have gas, will travel

A-level reportAS/A2 chemistry specifi cations –what’s new for 2008?

ISSN 0013-1350

Did you know?If you are under 16 and have a burning question which relates to molecules you can submit it to the annual Molecular Frontiers Inquiry Prize, and you might win an iPod or laptop computer for your trouble.

Run by the Molecular Frontiers Foundation, the competition aims to stimulate your natural curiosity and propensity to ask profound questions that may lead to new directions in scientific research and breakthrough technologies. On hand to help you find an answer to your question is a global network of scientists

who will guide you to accurate online resources as well as help you understand the science.

Each year in May a panel of leading scientists, including Nobel laureates, meet in Sweden to judge the entries received. The 20 girls and 20 boys who ask the best questions will receive a medal, certificate and a mobile device.

To submit your questions visit Moleclues (www.moleclues.org) – an online community for under 18s interested in the molecular sciences.

Smart housesEnergy-saving ideas for green, clean living

A day in the life of…Daniel Ford, research chemist

On-screen chemistryCan an inflated tyre save Bond down under?

plus…Q&AGo for gold!WebwatchPrize puzzles

Infochem is a supplement to Education in Chemistry and is published bi‑monthly by the Royal Society of Chemistry, Burlington House, Piccadilly, London W1J 0BA, UK. 020‑7437 8656, e‑mail: eic@rsc.org www.rsc.org/Education/EiC/index.asp

© The Royal Society of Chemistry, 2007 Published in January and alternate months. ISSN: 1752‑0533

In tHIS ISSue

Editor Kathryn Roberts

Assistant editor James Berressem

Design and layout Dale Dawson

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Our streets are littered with black marks caused by people who irresponsibly dispose of their chewed gum. Clearing up this mess can cost local councils more than £90 000 per year. Now UK scientists have developed a chewing gum which is easily removed from pavements, and it tastes great too.

Speaking at the recent BA Festival of Science, in York, Bristol chemist and chief scientific officer of Revolymer Professor Terence Cosgrove said that the gum’s low adhesion property is thanks to a special ingredient – a new type of polymer. The long-chain molecule comprises two different types of monomer, one of which is hydrophobic (oil-loving) and the other hydrophilic (water-loving).

Thanks to its affinity for oil, the polymer mixes easily with the other ingredients needed to make chewing gum. In Revolymer‘s Clean

nOn-StIck cHewIng gum

Gum it makes up some 10 per cent of the mix, substituting for some of the stickier components used in regular gum. But it is the polymer’s water-loving nature that gives the gum its non-stick property. When the gum is chewed, the hydrophilic parts of the polymer attract water in saliva, which forms a film around the gum. This film acts as a lubricant. ‘You always get a film of water around our gum and that is one of the reasons it is easy to remove and in some cases does not stick at all’, says Cosgrove.

In tests carried out on the streets of Bristol and North Wales Revolymer’s Clean Gum disappeared within 24 hours while other commercial gums remained stuck to paving slabs for at least eight days. Further studies showed that when left in rain water for several weeks the new gum breaks down into a fine white powder while regular gum remains a lump of plastic. The gum is also easy to remove from table surfaces, some shoes and even hair, with washing.

Revolymer has developed mint and lemon flavoured versions of its Clean Gum, both of which have performed well in taste tests. Cosgrove and his colleagues expect to find out in December whether their polymer has passed EU health and safety tests and been accepted as a food additive. If it does, non-stick gum could be on sale in early 2008. But for now if you like gum: chew it, wrap it, and bin it. n

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Smart energy homes

twenty-five per cent of the UK’s total electricity is used to power lighting and appliances in the home. If we do nothing this figure is predicted to rise

by 20 per cent by 2020 as the number of electrical products in our homes grows. This is unacceptable. The UK, along with the rest of Europe, is committed to tackling climate change by reducing CO2 emissions by 60 per cent by 2050 – 85 per cent of which is caused

by burning fossil fuels for energy. And with gas and oil reserves dwindling, Europe is faced with the challenge of reducing any future dependence on imported fuels and being able to deliver secure, clean and affordable energy. Against this scenario the concept of the Smart Energy Home (SEH) was born.

A collaborative effortIn August 2006 SusChem announced that from 2009 at least four ‘Smart Energy Homes’

would be built in major cities of Europe. (SusChem is a consortium of European chemical companies coming together to collaborate with construction and biotechnology companies, as well as major European professional bodies such as the Royal Society of Chemistry and the German Chemical Society. The aim of such collaboration is to exploit chemistry and chemical engineering research and bring sustainable products onto the market. )

In Europe, homes and businesses use more energy than any other sector, including transport. Heating, lighting and power appliances – from computers and gaming consoles to white goods – are inefficient to the extent that valuable energy is being wasted. What can we do to smarten up our homes?

Burning down the house…

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The Smart Energy Home initiative will bring together several technologies that together will eliminate the net use of energy in the home – any energy that is used in the house will be taken from something that gives energy. The major input from chemists will be in innovative materials for construction and insulation, lighting, windows, smart coatings and surfaces, and lower energy-consuming appliances.

nanofoamsNovel insulating materials are being developed by BASF chemists and physicists. They are currently focusing on polymer foams with pore sizes in the nanometre range – nanofoams.

Heat transfer through porous materials occurs through convection, conduction and radiation. Over the past 50 years BASF research scientists, by understanding the mechanisms of heat flow, have found that reducing the pore size of polymer foams to micrometres and incorporating certain

Smart energy homes

More recently, the BASF researchers have been investigating how they could reduce the thermal conductivity from these insulating foams even further. The answer came with the development of nanofoams – ie foams with pore diameters of up to several hundred nanometres. ‘This is approaching the mean free path of the molecules making up the air’, explains Kessenich – ‘ie the distance travelled before the molecule collides with another molecule. When the average pore size of a foam approaches the mean free path of the gas in the pores, there are essentially more gas–wall collisions than gas–gas collisions, and heat transfer by conduction through the pore is significantly decreased’. Nanofoams, just a few centimetres thick, could achieve the same level of insulation as a 50 cm-thick standard insulation foam.

Smart lightingLighting is another area where there are huge savings to be made. Too many homes still use incandescent bulbs, which produce light by passing an electric current through a thin tungsten filament. These bulbs are inefficient – 95 per cent of the energy is lost as heat. Energy-saving fluorescent light bulbs, which contain mercury, are more efficient by up to 25 per cent and last longer. However, within the next few years we should see a revolution in the way we light up our homes. Look out for OLEDs – organic light-emitting diodes.

Already used in some displays, OLEDs comprise an ‘emissive layer’ together with other conductive organic layers attached to a metal cathode (eg aluminium or calcium) on one side and a transparent anode (eg indium–tin oxide) »

additives eliminate heat loss through these materials by convection and radiation. Dr Elmar Kessenich, BASF chemist, told InfoChem, ‘the amount of radiation passing through an optically opaque medium, defined by the Beer–Lambert Law, is inversely related to the number of scattering centres in the medium, the effectiveness of the scatter, and the thickness of the sample. Because increasing the density of the foam would also increase the heat transfer by conduction, the best option for reducing radiative heat transfer is by modifying the effectiveness of scattering in the foam by adding strongly scattering particles’. The addition of graphite to polystyrene foam, for example, led to the material Neopor. In comparison to a standard polystyrene foam of the same density, the thermal conductivity of Neopor is 25 per cent lower, which translates to a reduction in raw material usage of up to 50 per cent.

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Issue 107 november 2007

not just bricks and mortar

The Smart Energy Homes will demonstrate and test a

variety of smart materials, new technologies and processes for the home.Renewable and clean energy sources, sensors to manage energy usage, innovative design, waste management and recycling systems, green consumables and energy-saving appliances will all feature in the houses.

Insulating nanopores

»

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on the other side. The emissive and conductive layers are thin films of semiconducting organic metal complexes, such as an iridium atom attached to pyridine (C5H5N) ligands. When a voltage is applied across the OLED the cathode gives electrons to the emissive layer and the anode withdraws electrons from the conductive layer, leaving holes for the electrons to move into. Holes and electrons combine to form ‘excitons’. If the exciton represents an excited state of the emitter, it can lose energy and relax to its ground state and emit light of a specific wavelength, depending on the energy levels of the molecule.

So far chemists have been able to produce green, red and blue light from OLEDs using fluorescent materials, and green and red light from more efficient phosphorescent materials. The challenge remains to produce a quality dark blue light, so that the combination of the three colours produces a strong white light that is at least as efficient as a fluorescent source. Kessenich expects the first commercial OLED product for specialised and decorative lighting to come on the market by 2010, though a prototype is likely to be used in the Smart Energy Homes. Bulbs and tubes will make way for aerial

lighting, which could be put on foils and wrapped around various objects around the homes or, if they can be made transparent, put on windows.

thermally-efficient windowsThermally-efficient triple-glazing is likely to be used for the Smart Energy Homes. One product, developed by the glass manufacturer, Scott, has an interior pane, made of an insulating plastic, which is coated with a transparent nanolayer of metal. The interior and exterior glass is separated with a non-conductive spacer, and the space is filled with krypton. The metal layer is connected to a power supply. The insulated glass keeps cold air out but lets sunlight (infrared radiation) through. When the power is switched on infrared heat is radiated into the room via the conductive metal. Large windows could provide enough heat to warm a room without the need for additional heating. In the future solar panels (which use photovoltaic cells to convert sunlight into electricity) on the roof of the Smart Energy Home could be used as the power source during the day for the windows, one step

closer to the ‘zero energy’ home.In the longer-term lies the possibility of

intelligent-coated glass. For example, thermochromic coatings, being developed by chemists at University College, London, operate on a phase change that occurs in vanadium oxide (VO2). Such coatings change the insulating and reflective properties of glass with temperature, making them potentially more efficient if the weather changes.

Intelligent coatings, specifically self-cleaning coatings, will be used on the facade of the houses, as well as more durable building materials that use less energy in their manufacturing process. Proctor and Gamble recently announced a new detergent that cleans at 20 °C, so people living in the energy-saving houses will be able to wash their clothes using less detergent, less water and less energy. Smart Energy Homes should be coming to your neighbourhood soon.kathryn Roberts

Smart glass!

“the Smart energy Home will eliminate the net use of energy in the home”Issue 107 november 2007

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A recent study of some of the oldest known rocks on Earth by geochemist Martina Menneken and her colleagues of the Westfälische Wilhelms University of Münster, in Germany, could rewrite the history of the planet. The researchers investigated 1000 zircon (zirconium silicate, ZrSiO4) crystals from the Jack Hills region of Western Australia. These zircons were thought to have formed several hundred million years after the Earth was formed. However, Menneken’s work suggests that these zircons might be older still.

Zircon crystals have survived unchanged throughout the ages, preserving information on how the Earth evolved during its early lifetime. Analysis of trace elements and their isotopes in these crystals provide an accurate measure of the material’s age, source etc.

Reporting their work in the journal Nature, the researchers used a sensitive high-resolution ion microprobe to analyse the ratio of lead

and uranium isotopes in the zircon grains, which pointed to their samples being ca 4250–3000 million years old. Using Raman spectroscopy, an analytical technique which uses laser light to probe a material’s composition and structure, the researchers were surprised to find tiny diamond inclusions in each sample.

The Earth formed some 4500 million years ago and scientists believe that it took the next 500 million years for the Earth to cool enough for rock to form. But such conditions would not have supported the formation of diamond in the team’s oldest zircon samples. Diamond forms only at high pressures, eg at the site of a meteorite impact or by the deep burial of rock in the Earth’s crust. Although unsure of how the diamonds were formed, the researchers suggest that the Earth was a lot quieter and cooler sooner than previously thought. n

dIAmOnd In cRuSt

Issue 107 november 2007Issue 106 september 2007

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In A view to kill, James Bond (Roger Moore) is knocked-out and pushed into a Silver Cloud Rolls-Royce. Hoping to drown Bond, the villains push the car into a lake. As the water pours into the car, he gains consciousness but instead of swimming up to the surface, where he will be seen, he stays under the water. He opens a car-tyre valve and breathes the air bubbles saving his life. Is this really possible?

To get a rough idea of the volume of a lung-full of air, we can blow into a balloon. We find it fills roughly halfway and that an inflated car tyre contains the equivalent of roughly 30 half-balloons or breathes. But is this the same under water?

When the valve is opened air rushes out until the pressure inside the car tyre is the same as that outside. Atmospheric air pressure is the result of the weight of air above us in the atmosphere. When we go under water the weight of water adds more pressure. The weight of a column of the Earth’s atmosphere going straight up 50 km or so is about the same as a similar column of

water just 10 m deep. If we go down deep enough the pressure

caused by the water will eventually be about the same as that in the car tyre (ignoring how the tyre itself collapses under the water pressure). If we now open the valve no air will come out. If we assume that the car goes down just a few metres then the pressure won’t be as great as this but less air will come out of the tyre than it would if it was on the surface. Let’s say that we now have the equivalent of 20 or so lung-fulls of air.

The air that comes out will be compressed by the water pressure but our lungs still require the same volume of air to breathe comfortably. The 20 lung-fulls will probably reduce down still further to about 15 lung-fulls (almost half the available air we would have had opening up the valve on the surface).

In the film we see that much of the air is bubbling away. If we say that half gets lost then that leaves Bond with about seven lung-fulls of air. If one lung-full allows him to stay under water for ca 30 seconds then we have a

total of ca three minutes of air. He also has another three tyres on the car so, theoretically, he could be down there for 10 minutes or so. However, not all air is breathable. Car tyres contain iron reinforcement strips which will oxidise over time, so there may be less oxygen in the car tyre than expected.

In the Hollywood Science TV series we did this experiment. We found we could breathe in air bubbles under water which displaced any water which also came in. When our heads were down each gulp of air pushed any water to the front of our mouths and we could swallow it. We found that we could stay under quite comfortably for as long as there was air – amazing!

Dr Jonathan Hare, The CSC Centre, Chemistry Department, University of Sussex, Brighton BN1 9ET (www.creative-science.org.uk/TV.html)

Jonathan Hare asks…undeR wAteR: can you survive by breathing in air from a car tyre?

007 – one step ahead of the villains

Forensicshttp://www.virtualmuseum.ca/Exhibitions/Myst/en/index.htmlYou have arrived at a crime scene where there appears to have been a break-in and a man is dead. In this interactive game, you will use your

deductive skills and forensic knowledge to piece together the evidence you need to identify the murderer. The database and timeline sections are also useful sources of information about forensic science. n

the poisoned needlehttp://antoine.frostburg.edu/chem/senese/101/features/domoic.shtmlThis website is for sixthformers wanting to extend their knowledge. Although written for US

undergraduates, many topics will be familiar. The poisoned needle shows how chemical separation techniques are invaluable in solving mysteries. You will also find stories about more complex molecules, eg the excellent Isomer construction set. n

Emma Woodley, RSC assistant education manager, takes a look at some websites of interest to students

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gO fOR gOld! Test yourself with questions from the International Chemistry Olympiad

This question is adapted from Q1 of the 2005 UK Round 1 Chemistry Olympiad paper.

Poisonous carbon monoxide may be detected by its ability to reduce an aqueous solution of palladium(ii) chloride to black metallic palladium (Pd).

(a) Draw a ‘dot and cross’ structure for carbon monoxide.

(b) Is the bond between the carbon and oxygen in carbon monoxide best described as a single, double or triple bond?

(c) Write the equation for the reaction between aqueous palladium(ii) chloride and carbon monoxide.

In addition to the two most common oxides – carbon monoxide and carbon dioxide – a few other compounds may be formed which contain carbon and oxygen only. Each of these oxides may be prepared by the dehydration of the appropriate organic acid.

‘Carbon suboxide’ is a foul-smelling gas obtained by fully dehydrating propan–1,3–dioic acid.

(d) Draw the full structural formula of propan–1,3–dioic acid.

(e) Write a balanced equation for the formation of carbon suboxide and water from propan–1,3–dioic acid.

(f) Draw a structure for carbon suboxide.

Web resourCesTo see the 2005 Olympiad paper (and answers!) go to: www.chemsoc.org/olympiad

To find out more about how to take part in the RSC Olympiad competitions for UK sixthform students go to:www.rsc.org/olympiad

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Did you know?‘Hard’ water contains calcium (and often magnesium) hydrogen carbonate and/or similar salts. Heat hard water and calcium carbonate precipitates out of solution. This is the limescale on your kettle’s heating element, which over time builds up. Products like Calgon contain citrate ions, which react with the limescale to form calcium citrate, which is water soluble.

Issue 107 november 2007

Q: How do liquid crystal displays produce different colours on computer screens? (Timothy from Osterley)Professor Stephen Kelly, University of Hull says: Liquid crystal displays (LCDs) use several methods to generate colour. The most common one is the use of absorption colour filters. LCD screens for computer monitors or laptop computers are made up of many tiny picture elements (pixels). A laptop computer or a computer monitor will have over two million colour pixels. White light passing through one of the pixels is changed into red, green or blue light by selective absorption of light by the colour filter. The intensity of light passing through an individual pixel can be controlled by changing the voltage. So mixing these three colours by intelligent electronics allows a multitude of other colours to be created. There are usually 256 shades for each red, green and blue pixel, so mixing the shades of each of these colour creates an almost unlimited number of other colours.

Colour can also be generated by the use of a guest dye in a liquid crystal host mixture. These guest–host LCDs are usually monochrome or black-on-white displays for clocks, watches, or large-area displays in airports or train stations. LCDs can also use destructive interference between rays of light to generate colours as in some of the first PDA and mobile phone LCDs.

(Liquid crystals are long, thin organic molecules that move under the action of an electric field either to block the passage of light through an LCD or to allow the light to be transmitted in a sort of light shutter, which basically is what an LCD is – an electronic light shutter.)

send your questIons to:The Editor, Education in Chemistry, the Royal Society of Chemistry, Burlington House, Piccadilly, London W1J 0BA or e-mail: eic@rsc.org.All questions published will receive a £10 HMV token.

Looking for answers to chemically related issues? Why not put them to InfoChem’s professional chemists…

Colourful display for PDAs

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Issue 107 november 2007

ReSeARcH cHemISt:Daniel Ford

A day in the life of…

Daniel Ford has spent the past four years working for UCB and his current position is research chemist. He talks to James Berressem about his typical day.

UCB is a biopharmaceutical organisation with R&D and manufacturing sites around the globe. The company develops treatments for severe diseases such as cancer, epilepsy, rheumatoid arthritis and Parkinson’s disease. Daniel is one of 20 chemists working on an R&D project to make new small molecule drugs that inhibit enzymes (called kinases) which cancer cells need to grow.

making moleculesDaniel works in a lab optimising lead compounds which have shown some potency against kinases. At UCB he is encouraged to be creative and contribute ideas to designing new molecules, rather than just synthesise compounds in the lab. UCB chemists have made many new molecules by making slight alterations to the structure of potential lead compounds in an effort to introduce the overall properties required for a viable drug, eg increasing its solubility. Daniel’s efforts continue in this vein and his first port of call in his search for ideas to modify a lead compound is the company’s database on molecules and their properties, or structure–activity relationships.

Before going home Daniel sets up a reaction to run over night. He records every experiment he does in a lab book, including details

such as time taken, reaction conditions etc. First thing in the morning Daniel does a liquid extraction and clean-up of the reaction mixture. Next he separates out the reaction products using solid-phase chromatography. The equipment is computer-controlled so Daniel can pre-programme the run and get on with other work, such as studying academic journals to learn about developments in relevant lab technology.

State-of-the-art facilitiesMany of the reactions require standard chemistry apparatus but new techniques are used in UCB’s labs. For example, Daniel uses a special microwave oven to heat reactions which do not take place when heated by a water or oil bath. He is particularly excited about using new microfluidic lab-on-a-chip devices. These allow chemists to do chemical reactions using microscopic volumes of chemicals. Working on this scale speeds up reactions and lowers chemical requirements, thus reducing cost, waste and risk.

Daniel must analyse and characterise every compound he makes, be it an isolated intermediate or a final product. He uses techniques such as liquid chromatography–mass spectrometry, NMR spectroscopy and ultra-high pressure liquid chromatography equipment, another new bit of kit in the lab which accurately measures the product’s purity – a vital consideration if it is to be made into a drug.

Back at his desk Daniel carefully inputs data on his latest product onto the database. He also writes a report which he will present at the chemistry team’s fortnightly meeting. The project team, including biologists and pharmacologists, meet once a month. This is an opportunity for Daniel to find out if any of his compounds have progressed through the screening programme.

the thrill of researchDaniel enjoys the hands-on aspect of chemistry and doing pioneering research – making molecules no one has made before is a thrill for him. And to work to a goal which one day might ease the suffering of many cancer patients is particularly rewarding. n

pAtHwAy tO SucceSS

2007–present, research chemist, UCB

2004–07, research associate, UCB, Slough

2003–04, contractor, Pfizer, Sandwich

1999–2003, BSc medicinal chemistry with year in industry (2.ii), Leeds University

1998–99, project worker, Pfizer, Sandwich

1996–98, chemistry and biology A-levels, Hind Leys Community College, Shepshed

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Daniel Ford

£50 of HMV tokens to be won!£50 of HMV tokens to be won!

September pRIZe wORdSeARcH no. �� winnerThe winner was Eleanor Smith of Ysgol Brynhyfryd, Ruthin, Denbighshire. The 10-letter word was SpERmICIDE.

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Students are invited to find the 35 words/expressions associated with astronomical observations hidden in this grid. Words read in any direction, but are always in a straight line. Some letters may be used more than once. When all the words are found, the unused letters, read in order, will spell a further six-letter word. Please send your answers to the Editor at the usual address to arrive no later than Friday 7 December. First correct answer out of the editor’s hat will receive a £10 HMV token.

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ATOMATOMIC HYDROGENAURORA BOREALISBIG BANGDUST GRAINSELECTRONSENERGYExPLODEDGASHUBBLE TELESCOPEINFRARED RADIATIONINTERSTELLAR

ION LITHIUMMARSMOLECULAR HYDROGEN

MOLECULE ExCHANGEMOLECULESNEUTRAL ATOMSNUCLEIOBSERVATIONSPHOTODISSOCIATIONPHOTON

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UCaNdO, supplied by University of Southampton chemist Dr Jeremy Hinks, is Benchtalk’s chemical take on the popular Japanese number puzzle, Su Doku. The puzzle comprises three tasks. The first is to complete the grid. The rules are the same as for numbers in Su Doku: a symbol can appear only once in each horizontal line, each vertical line and each block of nine squares set within the bold lines. All nine of the required element symbols are already shown in the grid. Once you have completed the grid you can attempt the next two tasks.

The elements used in the grid are a strange mixture – antimony, argon, cobalt, iodine, nitrogen, sulfur, tellurium, uranium and yttrium. There is no common chemical theme that links them together. However, together the element symbols form two words related to shopping. To identify the two words you will need to find out: (a) which one of the nine element’s symbol must be used twice; and (b) which element’s symbol occupies the bottom right square of the grid because the letters of this symbol must be used as two separate letters. So what are the two words?

On first inspection both these words are not obviously associated directly with science and technology. In fact, one of them is. Which one is it and why?

Please send you answers to: the Editor, Education in Chemistry, the Royal Society of Chemistry, Burlington House, Piccadilly, London W1J 0BA, to arrive no later than Friday 7 December. First out of the editor’s hat to have correctly completed the grid will receive a £15 HMV token. The first entry drawn to have identified the two mystery words, and which of these is linked to science and technology and why will receive a £25 HMV token.

ucandO no. ��

ucandO no. �� solutions and winnersLisa munro of The Ridings High School, Winterbourne, Bristol completed the grid. Nirupama Sharma also of the The Ridings High School correctly identified that all the elements in the grid are represented by symbols which are not (apparently) related directly to the full name of the element. The other element that shares this trait is antimony (Sb). Its symbol originates from the Latin word stibium for the ore stibnite (antimony sulfide).

Issue 107 november 2007

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