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Questions and answers should be concise. We reserve the right to edit items for clarity and style. Include a daytime telephone number and email address if you have one. Restrict questions to scientific enquiries about everyday phenomena. The writers of published answers will receive a cheque for £25 (or US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted by readers in any medium or format. New Scientist retains total editorial control over the content of The Last Word. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK, by email to [email protected] or visit www.last-word.com (please include a postal address in order to receive payment for answers). For a list of all unanswered questions send an SAE to LWQlist at the above address. THE LAST WORD don’t know the difference between the properties of the two cereals, I can give this advice to your correspondent. Soak the used Weetabix bowl for a few minutes, rather than a few seconds, before cleaning – it makes it much easier. David Purchase Bristol, UK Right way round Do standard anticlockwise running tracks favour right-handed runners? Do right-handers win disproportionately more track events than left-handers? If not, why? n I recently had to visit a physiotherapist, who found that my right leg is about 1 centimetre longer than my left (I am right- handed.) He told me that almost all right-handed people have longer right legs, and conversely almost all left-handed people have longer left legs. This gives right-handed people a natural lean to the left, so they may have an advantage on anticlockwise tracks, because it would seem to be easier for them to run round left-handed bends. This may even explain why anticlockwise tracks are used. This hypothesis could be tested by examining records for races run over different distances. The 100 metres, being run on a straight track, should show no bias towards one group or the other, as should the marathon. Records for in-between distances would be expected to show a bias in favour of right- handed runners. Bob Watson High Wycombe, Buckinghamshire, UK This week’s questions LOO CLUE 1 While on a cruise ship in Spitsbergen, Norway, we had to use toilets which would only flush if the lid was closed to create a seal. Sometimes you had to hold the lid down to ensure the seal was intact. How did they work? Melanie Green Hemel Hempstead, Hertfordshire, UK LOO CLUE 2 How do toilets on airliners work? They have incredible suction. Is the low external pressure outside the aircraft’s fuselage used to create this? And why do they operate a few seconds after you press the flush button? Lance Martel Lima, Peru IN THE ROUND I attended a concert at Sydney Opera House in Australia recently. The ceiling has doughnut-shaped structures hanging from it (see photograph). I presume they somehow enhance the music reaching the listener because I have seen similar structures in the Royal Albert Hall in London. What are they for and how do they work? Noah Jacob Sutherland, New South Wales, Australia SKEWED PERCEPTION If I sit upright in a chair to read a book, my wife thinks I am being intellectual. If I read the same book lying down on the sofa, she thinks I am being lazy. Is there any scientific basis for this perplexing feature of the human brain? John Gledhill Wellesbourne, Warwickshire, UK Last words past and present, plus questions, at last-word.com The latest collection: witty, brilliant, intelligent and packed with insight Available from booksellers and at www.newscientist.com/elephants Why can’t elephants jump? Cereal cement My two favourite breakfast cereals are Shreddies and Weetabix. When I’ve finished, the remnants in the bowl look similar, but I can always tell which was which: a Shreddies bowl can be washed up quite easily, while Weetabix clings like cement. Why the difference? n As a lifelong consumer of Weetabix, I feel qualified to answer this question. Both Shreddies and Weetabix contain a high proportion of starch, which can form an adhesive paste with water. This phenomenon is well known to bookbinders because it is used to make paper. Starch consists of a mixture of amylose and amylopectin, polymers that can absorb water to form a gel. As the gel dries, the water is expelled and bonds between the molecular chains reform, creating a semi- crystalline “cement” which will adhere to any adjacent surface. This effect is much more noticeable with Weetabix than Shreddies simply because Weetabix is made of fine flakes of cereal compressed together, while Shreddies are made from longer strands. That means Weetabix has a greater surface area of adhesive in contact with the bowl, making it more difficult to clean. Chris Sugden London, UK n I have no experience of Shreddies, but am familiar with the Weetabix problem. So while I
