- Email: [email protected]
Pastures new
The last word– AS TIME GOES BY Why does red wine become lighter in colour as it ages, but white wine become darker? (Continued)
● It was stated in a previous answer that “young wines in Portugal are called vinho verde”. This is in fact incorrect. Vinho verde is a wine made with certain types of grapes in a certain region of Portugal, and there are white and red vinhos verde. Although vinho verde should indeed be drunk while young (with the possible exception of alvarinho styles) the name itself does not imply youth. Antonio Brito Portugal
CUTTING COMMENTS If I use an electric razor with an oscillating cutter, should I run it over my beard slowly to catch as many hairs as possible or is it more efficient to pass it over the beard rapidly several times to increase the chance of catching missed hairs? Is there an optimum shaving speed?
● An optimum speed for dry shaving with an oscillating razor is 300 millimetres a second. A greater speed results in fewer than half the whiskers being severed on each pass, while slower rates do not give any better shave. Dry shaving leaves about 10 per cent more stubble (about 0.05 millimetres) than wetblade shaving. The longer ends left by the shaver mean the result Questions and answers should be kept as concise as possible. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and a fax if you have one. Questions should be restricted to scientific enquiries about everyday phenomena. The writers of all answers that are published will receive a cheque for £25 (or the US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted
feels rougher than the smooth surface that is left after wet shaving with a sharp blade. Jack Galligan Weston, Massachusetts, US
● It hardly matters. The significance of hair hysteresis, described some 30 years ago, is that a hair pulled out a millimetre or two by the tug of a razor typically takes about an eighth of a second to fall back in again. Twin-
“Manually repeating strokes with a single blade is strenuous, not to mention hazardous.” blade razors, followed by new generations of electric razors, were designed for the first blade to tug at the hair, then for the next blade to lop off the newly exposed length of bristle, thereby deferring 5-o’clock shadow by a few hours. The original research showed that even a slowly wielded twin-blade razor has its second bite at the cherry in well under the time it takes for a hair to retract. After all, with twin blades separated by about 1 millimetre, a slow stroke at a speed of 50 millimetres per second will hit a bristle more than five times as fast as necessary. Even if you manually repeated strokes five times per second with a single blade – which would be strenuous, not to mention hazardous – it would be inadequate for exploiting hair hysteresis. Good electric razors not only grab and stretch the bristle, but may take about 100 bites per second, so shave as you please. Jon Richfield Somerset West, South Africa by readers in any medium or format. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK (fax +44 (0) 20 7611 1280) or by email to [email protected] (all correspondents should include their postal address in order to receive payment for answers). If you would like a complete list of all unanswered questions please send an SAE to LWQlist at the above address.
Memorable answer? As part of our 50th anniversary we have teamed up with Crucial Technology (www.crucial.com/uk) and will be awarding each successful author a 512MB Gizmo! overdrive.
060916_R_Lastword.indd 149
Last Words past and present, plus a full list of unanswered questions, are available on New Scientist’s website at www.newscientist.com
PASTURES NEW I always associate lichen with church roofs or gravestones. Now I have found a patch on my car. Is this a metal-favouring species? What determines where lichen will grow?
● Are you sure that it is a lichen, and not just paint blistered by sun or corrosion? One reason to wonder is that most lichens grow slowly, and if that car has been in use long enough to display a recognisable patch, it must be quite old, or standing in an atmosphere rich in dust and organic vapours conducive to lichen growth near a pig pen, perhaps. Assuming it is a lichen, I imagine it is growing on a rust spot or a crack in the paint. If so, this is not surprising. The fungal growth that forms the lichen’s support tissue attaches strongly to insoluble substrates, such as ferric oxide. This lichen might be a species adapted to growing on heavymetal ores, but even if it is not, the dust and organic adhesives that attach the growth to the substrate should form a barrier against toxic concentrations of iron compounds. Antony David Edinburgh, UK
the clean air of this part of the world lichens grow on trees, all types of roofs, masonry and even the tarmac of some little-used roads. They are generally harmless (although some lichens cause weathering of stone) and I generally leave them alone, with the exception of lichens growing on the collectors for my solar water heater. Brian Burbage Inverleigh, Victoria, Australia
THIS WEEK’S QUESTION Gone fishing On a field course in the foothills of the French Alps in July 2006, some of our students noticed a seemingly intact duck egg in a small pond. It clearly contained something moving. When we broke the shell we found three live minnows (Phoxinus phoxinus) inside (see Photo). Do any readers know for sure how the fish ended up here? Matthew Cobb and Henry McGhie University of Manchester, UK
● As lichens need only light and moisture to grow, they colonise many areas. They are slow growing, however, and cannot overcome competition, which limits them to areas unsuitable for conventional plants. Atmospheric pollution greatly curtails the growth of many lichens and their presence can be taken as an indicator of good air quality. In
Does Anything Eat Wasps? New Scientist’s latest collection from The Last Word, answering some of the world’s most baffling questions Available in bookstores and online
8/9/06 3:18:29 pm
● It was stated in a previous answer that “young wines in Portugal are called vinho verde”. This is in fact incorrect. Vinho verde is a wine made with certain types of grapes in a certain region of Portugal, and there are white and red vinhos verde. Although vinho verde should indeed be drunk while young (with the possible exception of alvarinho styles) the name itself does not imply youth. Antonio Brito Portugal
CUTTING COMMENTS If I use an electric razor with an oscillating cutter, should I run it over my beard slowly to catch as many hairs as possible or is it more efficient to pass it over the beard rapidly several times to increase the chance of catching missed hairs? Is there an optimum shaving speed?
● An optimum speed for dry shaving with an oscillating razor is 300 millimetres a second. A greater speed results in fewer than half the whiskers being severed on each pass, while slower rates do not give any better shave. Dry shaving leaves about 10 per cent more stubble (about 0.05 millimetres) than wetblade shaving. The longer ends left by the shaver mean the result Questions and answers should be kept as concise as possible. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and a fax if you have one. Questions should be restricted to scientific enquiries about everyday phenomena. The writers of all answers that are published will receive a cheque for £25 (or the US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted
feels rougher than the smooth surface that is left after wet shaving with a sharp blade. Jack Galligan Weston, Massachusetts, US
● It hardly matters. The significance of hair hysteresis, described some 30 years ago, is that a hair pulled out a millimetre or two by the tug of a razor typically takes about an eighth of a second to fall back in again. Twin-
“Manually repeating strokes with a single blade is strenuous, not to mention hazardous.” blade razors, followed by new generations of electric razors, were designed for the first blade to tug at the hair, then for the next blade to lop off the newly exposed length of bristle, thereby deferring 5-o’clock shadow by a few hours. The original research showed that even a slowly wielded twin-blade razor has its second bite at the cherry in well under the time it takes for a hair to retract. After all, with twin blades separated by about 1 millimetre, a slow stroke at a speed of 50 millimetres per second will hit a bristle more than five times as fast as necessary. Even if you manually repeated strokes five times per second with a single blade – which would be strenuous, not to mention hazardous – it would be inadequate for exploiting hair hysteresis. Good electric razors not only grab and stretch the bristle, but may take about 100 bites per second, so shave as you please. Jon Richfield Somerset West, South Africa by readers in any medium or format. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK (fax +44 (0) 20 7611 1280) or by email to [email protected] (all correspondents should include their postal address in order to receive payment for answers). If you would like a complete list of all unanswered questions please send an SAE to LWQlist at the above address.
Memorable answer? As part of our 50th anniversary we have teamed up with Crucial Technology (www.crucial.com/uk) and will be awarding each successful author a 512MB Gizmo! overdrive.
060916_R_Lastword.indd 149
Last Words past and present, plus a full list of unanswered questions, are available on New Scientist’s website at www.newscientist.com
PASTURES NEW I always associate lichen with church roofs or gravestones. Now I have found a patch on my car. Is this a metal-favouring species? What determines where lichen will grow?
● Are you sure that it is a lichen, and not just paint blistered by sun or corrosion? One reason to wonder is that most lichens grow slowly, and if that car has been in use long enough to display a recognisable patch, it must be quite old, or standing in an atmosphere rich in dust and organic vapours conducive to lichen growth near a pig pen, perhaps. Assuming it is a lichen, I imagine it is growing on a rust spot or a crack in the paint. If so, this is not surprising. The fungal growth that forms the lichen’s support tissue attaches strongly to insoluble substrates, such as ferric oxide. This lichen might be a species adapted to growing on heavymetal ores, but even if it is not, the dust and organic adhesives that attach the growth to the substrate should form a barrier against toxic concentrations of iron compounds. Antony David Edinburgh, UK
the clean air of this part of the world lichens grow on trees, all types of roofs, masonry and even the tarmac of some little-used roads. They are generally harmless (although some lichens cause weathering of stone) and I generally leave them alone, with the exception of lichens growing on the collectors for my solar water heater. Brian Burbage Inverleigh, Victoria, Australia
THIS WEEK’S QUESTION Gone fishing On a field course in the foothills of the French Alps in July 2006, some of our students noticed a seemingly intact duck egg in a small pond. It clearly contained something moving. When we broke the shell we found three live minnows (Phoxinus phoxinus) inside (see Photo). Do any readers know for sure how the fish ended up here? Matthew Cobb and Henry McGhie University of Manchester, UK
● As lichens need only light and moisture to grow, they colonise many areas. They are slow growing, however, and cannot overcome competition, which limits them to areas unsuitable for conventional plants. Atmospheric pollution greatly curtails the growth of many lichens and their presence can be taken as an indicator of good air quality. In
Does Anything Eat Wasps? New Scientist’s latest collection from The Last Word, answering some of the world’s most baffling questions Available in bookstores and online
8/9/06 3:18:29 pm