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Crying foul
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THE LAST WORD Rumble of doubt
normally, or is there some scientific method that ensures the youngster doesn’t feel pain? Ken Lee Hervey Bay, Queensland, Australia
How are internal body noises such as stomach rumbles produced, and why can we hear them?
n There is always gas in the human gut, mostly hydrogen, nitrogen, carbon dioxide and methane. This gurgles about in a semi-liquid substrate. Vibrations in our gut generate audible sounds just like the skin of a drum does. Central-heating systems also produce gurgling noises, which are caused by trapped gases. The noises go away after “bleeding” the radiators to release them. We bleed our stomach and bowels by burping and farting. Hugh Hunt Cambridge, UK
Sunshine down under I read in New Scientist that exposure to the sun in winter at latitudes higher than about 35° results in negligible vitamin D production (9 August 2014, p 34). For many years here in Tasmania (40° south) I have been exercising naked in the sun just after midday to dose up on vitamin D. But have I been wasting my time in winter?
Lake shawls
While walking around Lake Matheson in New Zealand, I came across many of these cocoon-like structures in a field of shrubs (see photo). What exactly are these? Rhea Tan London, UK Big bug zoo
angles above a latitude of 35°, it is possible for UVB to penetrate the atmosphere. I live in Oregon (45° north) and have been measuring ultraviolet radiation for several years. During the winter months, a clear day can have as much UVB radiation as 100 microwatts per square centimetre at sea level. This is between 25 and 30 per cent of the UVB we receive in midsummer and about 20 per cent of the levels seen in the tropics. For a person with fair skin, adequate vitamin D is produced by 15 minutes of summer exposure, or an hour during midwinter. Those with
n Contrary to what many experts report, anyone exercising naked at midday during the Tasmanian winter may well be receiving enough ultraviolet radiation to “Anyone exercising naked produce adequate vitamin D. Only ultraviolet-B (UVB) radiation at midday in Tasmania may receive enough UV to make is used for the production of adequate vitamin D” vitamin D, and at low winter sun
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
more melanin in their skin need more sun exposure. However, the questioner should make sure he continues his exposure at midday because UVB levels drop off within two hours on either side of the highest sun angle. Of course, cloud cover, rain and snow all severely reduce or eliminate UVB – but then, they also make it hard to exercise naked. Stephen Johnson Eugene, Oregon, US
This week’s questions Crying foul
Babies in TV or films are frequently depicted crying. How are they made to do this? Does the director wait for the child to cry
If insects grew to large sizes because of higher oxygen levels in the past, could we selectively breed insects in an oxygen-rich environment and create a Jurassic Park of insects? Sam Scott By email, no address supplied Terracotta solder
I put a piece of damp terracotta into my brown sugar to keep it crumbly. Why does the same process make icing sugar fuse into a solid brick? Kerry Graf Florey, ACT, Australia Ocean dwellers
Has any thought been given to the idea of building cities on the sea? Surely the technologies exist to make this a realistic alternative to destroying more agricultural land, and potentially even allowing us to benefit from sea level rises. Peter Hoare Ashwicken, Norfolk, UK
Question Everything The latest book of science questions: unpredictable and entertaining. Expect the unexpected Available from booksellers and at newscientist.com/questioneverything
THE LAST WORD Rumble of doubt
normally, or is there some scientific method that ensures the youngster doesn’t feel pain? Ken Lee Hervey Bay, Queensland, Australia
How are internal body noises such as stomach rumbles produced, and why can we hear them?
n There is always gas in the human gut, mostly hydrogen, nitrogen, carbon dioxide and methane. This gurgles about in a semi-liquid substrate. Vibrations in our gut generate audible sounds just like the skin of a drum does. Central-heating systems also produce gurgling noises, which are caused by trapped gases. The noises go away after “bleeding” the radiators to release them. We bleed our stomach and bowels by burping and farting. Hugh Hunt Cambridge, UK
Sunshine down under I read in New Scientist that exposure to the sun in winter at latitudes higher than about 35° results in negligible vitamin D production (9 August 2014, p 34). For many years here in Tasmania (40° south) I have been exercising naked in the sun just after midday to dose up on vitamin D. But have I been wasting my time in winter?
Lake shawls
While walking around Lake Matheson in New Zealand, I came across many of these cocoon-like structures in a field of shrubs (see photo). What exactly are these? Rhea Tan London, UK Big bug zoo
angles above a latitude of 35°, it is possible for UVB to penetrate the atmosphere. I live in Oregon (45° north) and have been measuring ultraviolet radiation for several years. During the winter months, a clear day can have as much UVB radiation as 100 microwatts per square centimetre at sea level. This is between 25 and 30 per cent of the UVB we receive in midsummer and about 20 per cent of the levels seen in the tropics. For a person with fair skin, adequate vitamin D is produced by 15 minutes of summer exposure, or an hour during midwinter. Those with
n Contrary to what many experts report, anyone exercising naked at midday during the Tasmanian winter may well be receiving enough ultraviolet radiation to “Anyone exercising naked produce adequate vitamin D. Only ultraviolet-B (UVB) radiation at midday in Tasmania may receive enough UV to make is used for the production of adequate vitamin D” vitamin D, and at low winter sun
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
more melanin in their skin need more sun exposure. However, the questioner should make sure he continues his exposure at midday because UVB levels drop off within two hours on either side of the highest sun angle. Of course, cloud cover, rain and snow all severely reduce or eliminate UVB – but then, they also make it hard to exercise naked. Stephen Johnson Eugene, Oregon, US
This week’s questions Crying foul
Babies in TV or films are frequently depicted crying. How are they made to do this? Does the director wait for the child to cry
If insects grew to large sizes because of higher oxygen levels in the past, could we selectively breed insects in an oxygen-rich environment and create a Jurassic Park of insects? Sam Scott By email, no address supplied Terracotta solder
I put a piece of damp terracotta into my brown sugar to keep it crumbly. Why does the same process make icing sugar fuse into a solid brick? Kerry Graf Florey, ACT, Australia Ocean dwellers
Has any thought been given to the idea of building cities on the sea? Surely the technologies exist to make this a realistic alternative to destroying more agricultural land, and potentially even allowing us to benefit from sea level rises. Peter Hoare Ashwicken, Norfolk, UK
Question Everything The latest book of science questions: unpredictable and entertaining. Expect the unexpected Available from booksellers and at newscientist.com/questioneverything