Thought for the month
“In the choice between changing one’s mind and proving there is no need to do so, most people get busy on the proof.” John K. Galbraith, Economist (1908 – 2006).
Monday, 22 April 2013
Much to Mrs Grange’s delight, Wales thrashed England at rugby last month. The rugby world may want to learn a bit of tribology, courtesy of Sheffield University who have been measuring the dynamic friction between the ball, the skin and the fingerless gloves or mitts that some players wear. Most rugby balls are made with pimples on the surface to improve handling. In dry conditions with no mitts, balls with more closely spaced pimples were better for grip. But in wet or muddy conditions, the density of the pimples allowed a film of moisture to form between them, so when wet, a ball with wider pimple spacing is better. Synthetic leather mitts produced the best performance across all conditions as the imposed texture interlocked best with the pimples on the ball.