Science - Mass protests

It's a close shave for athletes who need to lose weight

Andrew Hanson

Haircuts can make the difference between winning and losing competitions. And not just The X Factor. In sport, every hair counts. Mass - the quantity we feel and measure as weight - is measured in every area of sport to validate equipment and divide athletes into competition groups.

In the 2010 Commonwealth Games, when scale readings deemed certain competitors too heavy to qualify for their weight categories, some boxers decided to shave their heads as a swift means to shed weight and change the measurement of their mass. (It was eventually discovered that the scales used to measure their mass were at fault.)

This demonstrates that equipment used to record sporting measurements only works properly if it is checked against a known unit - or calibrated. For mass, all measurements are currently traceable back to a single lump of metal (the international prototype of the kilogram) kept just outside Paris.

If an item of equipment is a few grams heavier or lighter than specified, the athlete could be disqualified, so highly accurate weighing machines are essential. Olympic weightlifting rules require weighing machines to be accurate to 0.005 per cent.

Accuracy of measurement will play a vital role in the London 2012 Olympic and Paralympic Games, from gauging performance to distinguishing winners and verifying records. A new set of posters from the National Physical Laboratory (NPL) - the UK's national measurement institute - encourages teachers and students to bring the Games into the classroom and discover the science behind sport.

Each poster considers what impact units and scales will have on Olympic and Paralympic sports; for example:

- Pressure: how does pressure measurement in inflatable sports balls ensure fairness in football and volleyball?

- Distance: how do we know a metre rod is a metre long?

- Speed: how is frequency used to calculate the speed of a tennis ball?

- Time: how does measurement ensure that clocks used in the 100m final are accurate?

Andrew Hanson ( was a senior scientist at NPL before becoming its outreach manager. The posters are available at

What else?

For more information on NPL's education outreach go to

Relate the Olympics to science and maths with cartoons from Millgate House Education.

Get pupils solving problems on speed and streamlining with CSnewin's "pass the buck" activity.

In the forums

How would you go about creating all the Olympic colours in a key stage 3 chemistry lesson?

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Andrew Hanson

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