Secondary Secondary Science

Chemical Olympics

Chemistry is involved in everything we do – the materials that we use to construct buildings, tools and machines, the fuels we burn, the foods we eat and the way our bodies work. Here we look at some of the special ways that Chemistry is used in the London 2012 Olympic Games.

The Medals

The Olympics is all about the men and women who are “faster, higher, stronger”. The successful competitors are awarded gold, silver and bronze medals. The gold medal weighs 400g but is mainly an alloy made up of 92.5% silver, coated with 6g of gold. The metal in the medal is worth about £500. The silver medal is the same silver alloy. The bronze medal is an alloy of copper, tin and zinc. The precious metals were provided by the mining company Rio Tinto and mined in the USA and Mongolia.

The Stadium

For the duration of the games the main Olympic stadium has a wrapping. This is made of polyester coated with polyethene. The manufacturer, DOW, say that the material will be re-used after the games to help sustainability. The role of the DOW company has caused some protests because in 2000 they took over the company, Union Carbide, that caused the chemical disaster at Bhopal, India in 1984.

Materials

In many sports, winning involves getting the best materials. One example is the pole vault. The jumper carries the pole which can be up to 5.3m long. The pole bends as the jump begins and then springs straight to loft the jumper over the bar. The world record prior to London 2012 was 6.14 m. The materials used for the pole must be strong, flexible, elastic and as light as possible. The earliest poles were made of wood (ash or bamboo) then aluminium tube was used.

Next was glass fibre reinforced resin around an aluminium core. Today carbon fibres have replaced the glass fibres. Carbon fibre reinforced plastic, developed in the 19060s, is used in many other sports such as in tennis racquets, bicycle frames, rowing and sailing boats, arrows, and the blades used by footless runners like Oscar Pistorius. The material is a composite in which tiny fibres of graphite about 6 nanometres in diameter and a few micrometres long are embedded in a polymer. The fibres give the material its tensile strength and elasticity. The next step is to use carbon nano tubes as the fibres. With their more perfect arrangement of carbon atoms they will be even stronger and lighter.

Another important material in Olympic sports is Kevlar, developed 40 years ago. It is a polyamide like nylon but it is much stronger. This is because each repeating unit is a hexagonal benzene ring of six carbon atoms. The polymer chains are very flat and rigid and pack tightly together. They are bound strongly by hydrogen bonds. Kevlar is produced as fibres that are woven into a cloth which is extremely strong but also light. One of the first uses of Kevlar was in bullet-proof vests and the Olympic security staff will no doubt be equipped with them. Most of the athletes will be wearing shoes with Kevlar soles to withstand the force of pounding the track. Sailing boats will use Kevlar sails to exploit the force of the wind and fencers wear clothing reinforced with Kevlar for extra protection.

Drug testing

Catching the cheats is one of chemistry’s biggest tasks. There are about 400 banned substances that some sportsmen and women think may help their performance. They include the steroids used to build muscle, stimulants, growth hormones and many more. At London2012 the testing will be carried out at pharmaceutical company GlaxoSmithKline’s site at Harlow, Essex, run by the King’s College London Drug Control Centre. Over 6000 samples of urine and blood will be analysed by 150 scientists using all the techniques available. First of all Liquid Chromatography -Mass Spectroscopy (LCMS) separates the substances in the sample and identifies them. Some banned substances are more difficult to spot so Gas Chromatography-Mass Spectroscopy (GC-MS) is used. Isotope Ratio-Mass Spectroscopy (IR-MS) which measures the ratio of carbon-13 to carbon-12 sorts out synthetic compounds from similar ones that occur in the body naturally.

That’s just a few of the applications of chemistry at the Olympics – don’t the chemists deserve a medal too?

Activities

1. Choose a sport and investigate how chemistry is used to help the sportsmen and women.

2. Look at the sports equipment that you use – shoes, clothes, bats etc. Find out what materials they are made of. How do the properties of the materials match their use in the sport?

3. Find out about the development of materials such as carbon fibres and Kevlar.

4 (A level) Find out how liquid gas chromatography linked to a mass spectrometer works.

5. Go to the Royal Society of Chemistry’s website on Chemistry in the Olympics for other things to do. http://www.rsc.org/learn-chemistry/Collections/sport/

Peter Ellis July 2012

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