Volume 16 Iron oxide GCSE Science Review Number 3 (haematite) February 2006 Coke Limestone Waste Waste gases gases carbon carbon monoxide dioxide Iron CO + FeO CO + Fe + + forms 2 iron oxide iron carbon Carbon dioxide carbon monoxide CO2 + C 2CO + monoxide forms carbon carbon carbon + Carbon C + O2 CO2 oxygen dioxide dioxide forms Air Air blast blast Molten slag Molten iron Nanotechnology The front cover shows a nanofantasy, with medical nanorobots on red blood cells inside a human body (Victor Habbick Visions/SPL). Volume 16 Number 3 February 2006 Contents Looking ahead 1 Nanotechnology ometimes in the dark days of winter it seems that there will Snever be an end to coursework — but there is. Take a David Sang moment to think about how good you will feel when you hand it in — you deserve success because you’ve worked hard and, 4 Improve your grade most importantly, followed the advice you’ve been given in the Formulae last few issues of CATALYST. Those of you in year 11 have probably been thinking about 6 Your future what you are going to do next — A-levels? GNVQs? Will you Radiography stay at your own school or move to a college? Don’t forget to look through past issues of CATALYST — we have covered a wide 8 Plants and mineral nutrients range of careers and given you good advice on how to gain entry to them. If you think you want to go into medical imaging Nigel Collins or radiography after reading our articles then you’re in luck 11 Radioactivity in medicine because you can find out all about it on pages 6–7. Emily Cook Jane Taylor 14 Places to visit Free book for every subscriber! Ironbridge A single subscription to CATALYST, Volume 16, 2005/2006 is available to individuals at £16.95 per annum. Bulk orders of three or more subscriptions are available at the 16 Places to visit greatly reduced rate of £8.95 per subscription, provided all copies can be mailed to the same addressee for internal distribution. CATALYST is published four times The Science of Aliens through the school year, in September, November, February and April. Orders can be placed at any time during the year, and the issues already published will be supplied 17 Iron automatically. Only orders for complete volumes can be accepted. Every subscriber will also receive a copy of Philip Allan Updates’ GCSE Science Exam Paul Silverwood Revision Notes (worth £5.95) FREE with the November issue. This offer applies only to UK subscribers. 20 A life in science The above rates apply only for UK addresses. Overseas rates are available on request. Gertrude B. Elion Enquiries For more information or to place an order, contact CATALYST Subscriptions at 22 Chemistry in a blast furnace Philip Allan Updates. Published by Philip Allan Updates, Editorial team Advisory panel Market Place, Deddington, Oxfordshire OX15 0SE. Nigel Collins Eric Albone Ken Mannion Toru Okano tel: 01869 338652 King Charles I School, Clifton Scientific Trust Sheffield Hallam The Rikkyo School in Kidderminster University England fax: 01869 337590 Tessa Carrick Founder Editor, CATALYST e-mail: [email protected] Andrew Morrison John Rhymer David Moore David Chaundy www.philipallan.co.uk Particle Physics and Bishop’s Wood St Edward’s School, Founder Editor, CATALYST Environmental Astronomy Research Oxford Peter Finegold Education Centre © PHILIP ALLAN UPDATES 2006 The Wellcome Trust Council ISSN 0958-3629 Nigel Thomas David Sang Peter Jones Jill Nelson Author and editor Science Features, BBC Science Enhancement Publishing Editor: Catherine Tate. British Association Programme Design and artwork: Gary Kilpatrick. Sarah Leonard Science Museum Silvia Newton Reproduction by De Montfort Repro, Leicester. Jane Taylor Charlotte Wreton Sutton Coldfield Ted Lister Cheshunt School and Biotechnology and Printed by Raithby, Lawrence and Company, Leicester. Grammar School Royal Society of Chemistry Association for Science Biological Sciences Printed on paper sourced from managed, sustainable forests. for Girls Founder Editor, CATALYST Education Research Council L P S / s i r r a David Sang H r e g o R A nanofantasy. A nanorobot is shown injecting drugs which will kill a cancer cell. This technology is far beyond anything which might be achieved in the near future Nanotechnology Nanotechnology is the science of building tiny devices. Some people say that nanotechnology GCSE key words will be the answer to many of our biggest challenges — in medicine, electronics, defence and Resistance other areas of research. Others say that we are opening up a dangerous world of technologies Catalyst which could get out of control, causing more problems than they solve. Who is right? Sensors SI units ano’ is a prefix in the SI system of units. It This could transform medicine. Or imagine a SI prefixes means one billionth, or 10−9, so one nano- transistor, one hundred-thousandth of the size of milli = 10−3 ‘N metre is a billionth of a metre, or 10−9 m. The those in today’s computers. That could allow greatly micro = 10−6 diameter of an atom is in the order of 10−10 m, or one increased computing speeds. nano = 10−9 12 tenth of a nanometre, so a nanoscale object is made pico = 10− −15 of thousands of atoms. Compare this with the 1028 or Today’s nanotech products femto = 10 atto = 10−18 so atoms in a typical human being. Before the advent Nanotechnology is in its infancy, but we already make of nanotechnology, the smallest objects we could use of some nanoproducts. make were described as microscopic; now we have nanoscopic devices. Sun screen Some types of paint, Nanotechnologists have invented techniques for The sun screen which you rub into your skin to used by artists for producing nanoscopic machines, as well as sensors protect you from harmful ultraviolet radiation centuries, have been and electronic components. Imagine an electric contains nanoparticles of titanium dioxide (TiO2). found to contain motor so small that it could fit inside a single cell. Titanium dioxide is the ultra-white chemical used in nanoscale particles. February 2006 1 L P S / Box 1 Cancer diagnosis r e g e t When patients have cancer, their bodies produce a S r e k range of substances known as ‘biomarkers’. These l o V are characteristic of the disease. At present, blood and urine tests are used to detect just one or two of these substances, and they are often highly inaccurate — a patient may be diagnosed with prostate cancer, for example, when in fact he is free of the disease. Now Professor Jim Heath and his team at the California Institute of Technology have built a nanosensor capable of detecting and measuring many biomarkers simultaneously. Here is how it works. A blood sample passes over an array of nanowires. The nanowires are coated with antibodies to which the biomarkers bind; each nanowire is coated with a different antibody. The white paint; tiny particles of it are very efficient at Above: Coloured SEM biomarkers become stuck to the nanowires, and this absorbing UV radiation. Each particle contains of a micro-accelerator changes the wires’ electrical resistances. Electronic roughly 1019 atoms — that is quite a lot, on the from a car’s air bag. circuits measure the resistances of the wires, and nanoscale. Each square is a tiny from this it is possible to deduce which biomarkers pressure sensor. Car air bags are present. A detailed diagnosis can then be made A pencil tip is shown Car air bags use a nanotech sensor to trigger them. of the cancer type and its stage of development. for scale The sensor contains a nanoscale capacitor, formed The nanowires used by Heath are made of silicon. of two plates with opposite electric charges. When Each wire is less than 20 nanometres thick. the car decelerates suddenly, the plates are pushed together, changing the device’s capacitance. This is Already, there has been good progress in making detected by an external circuit which activates the nanosensors which can detect signs of disease in release of the air bag in a matter of milliseconds. blood and urine samples (see Box 1). Soon, we may Self-cleaning windows have nanomachines for targeting drug delivery to Self-cleaning windows Self-cleaning windows are now fitted in many modern appropriate sites in the body — at present, patients have very low friction. high-rise buildings. These have a nanofilm of titanium take medication which spreads throughout their The same technology dioxide which acts as a catalyst, causing organic dirt bodies, when it would be more effective if it were can be used to lubricate on the glass to react with sunlight, so that it washes delivered to just one type of tissue. wheels and gears in off. nanomachines. Energy Coming up Energy is a major concern in the twenty-first century. Nanoscale catalysts may soon be used to produce What can we expect from nanotechnology in the near more efficient burning of fuels, for example in car future? There are several areas in which it is likely to engines. Catalytic converters in car engines use the contribute (see Table 1). expensive metal platinum in a honeycomb form to Medicine and healthcare give a large surface area on which fuel and oxygen can Medicine and healthcare are areas where a large react. Nanoparticles of platinum would give the same amount is spent on research each year, so we can surface area for much less platinum. This would cut expect significant developments in the future. the costs of converters dramatically. It is now almost Table 1 Uses of nanotechnology 50 years since the Area Current Near future Distant future physicist Richard Feynman issued a Energy Nanocatalysts Nanomaterials for fuel cells and challenge.