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Feel the heat
Last words past and present at newscientist.com/lastword
THE LAST WORD Feel the heat On a beautifully sunny, windless day last summer, I sat in my back garden and felt very warm indeed. The air temperature was 16°C, but there is no doubt that it felt more like a day when the thermometer read 25°C. Why the discrepancy? (Continued)
n A further factor that should be considered is that the humidity may have been higher on that day than on another 16°C day. When the humidity level is high, the body cannot transfer heat to the atmosphere via perspiration as quickly. This will cause you to feel warmer or cooler even when the temperature remains the same. Since 2015, I have been on the medical staff for the Badwater Ultramarathon, which is held in Death Valley, California, every year in July. During times when the humidity is around 5 to 10 per
unsupported, using buried caches of food and water. The summer monsoon started in that area about three days into our trek and the high humidity at times, along with the high temperatures, made parts of it much more difficult. It is very easy to “feel” the higher humidity when it’s 46°C or more, and much more comfortable at that temperature as the humidity level drops. Dave Heckman Ashland, Oregon, US
Flat about fizz Why does my wife like wine with bubbles more than flat wine? Do the bubbles add to the taste or does her preference come from marketing and cultural context? And why do I not like fizzy wine?
cent, the runners can handle the 49°C temperatures much better than when it gets towards 15 per cent humidity. The medical staff see far more runners with heatrelated problems as the humidity level climbs. In July 2012, my friend Marshall Ulrich and I were the first to circumnavigate Death Valley National Park on foot,
n This is most likely a learned behaviour. Laboratory animals won’t drink carbonated liquid, and people adjust to the feel of it (or don’t) in the same way as they do to the bitterness of coffee or to spicy food. Surprisingly, the bite you feel from the fizz doesn’t come from the bubbles popping. When scientists got people to drink carbonated water in a hyperbaric chamber – where bubbles couldn’t form but the carbon dioxide was still present in the liquid – subjects reported the same sensation. Instead, it comes from a sour receptor called TRPA1, which is activated by carbonic
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. New Scientist 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.
“Medical staff see far more runners with heat-related problems as the humidity level climbs”
acid. A protein in your mouth called carbonic anhydrase converts the carbon dioxide to this acid, and the TRPA1 receptor detects this. At high acid levels your body goes into “get it out” mode and you will start coughing, choking and tearing up. But at low levels, the fizzy burn is pleasant for many people. The acid also makes sweet things taste less sweet – just consider how much sugar is hidden in one glass of cola. So the carbon dioxide changes the taste too. The same scientists found that once the acid sensation is present, injecting bubbles around the tongue enhances the feeling –
“Laboratory animals won’t drink carbonated liquid, and humans adjust to the feel of it (or don’t)” even if the bubbles are just plain air. The mechanism for this is unknown. So, if you don’t like fizzy wine, the most likely reason is you probably prefer sweetness or you don’t find the acid bite pleasant. Ron Dippold San Diego, California, US
This week’s questions SHADOW OF A DOUBT
Sitting outside with my back to the sun, I noticed that the shadow cast by the clear lens of my glasses
was equally as dark as that cast by the frame and my head. Why? Surely the clear lens would let the light through rather than casting a shadow? Richard Batho Jersey, Channel Islands I SPY EWE
After I released a lamb that had got its head stuck in a fence, it ran halfway across the field to a ewe and immediately started suckling. I heard no calling, so how did the lamb recognise its mother from all the other ewes it ran past? It can hardly have been the coat she was wearing. Gillian Coates Trefor, Anglesey, UK HAIR OF THE DOG?
I’ve watched TV documentaries that show people’s pets receiving chemotherapy. It doesn’t seem to cause them to lose their fur or hair, unlike humans. Why? Ann Wills London, UK STING IN THE TAIL
Mosquito bites frequently induce a sharp sting in people and some animals, with severe evolutionary consequences for the mosquito when it gets swatted. Are any mosquitoes evolving with delayed-action stings or reduced sting secretions so they can drink blood without the threat of imminent death? Clive Wilkinson Reef and Rainforest Research Centre Townsville, Queensland, Australia
THE LAST WORD Feel the heat On a beautifully sunny, windless day last summer, I sat in my back garden and felt very warm indeed. The air temperature was 16°C, but there is no doubt that it felt more like a day when the thermometer read 25°C. Why the discrepancy? (Continued)
n A further factor that should be considered is that the humidity may have been higher on that day than on another 16°C day. When the humidity level is high, the body cannot transfer heat to the atmosphere via perspiration as quickly. This will cause you to feel warmer or cooler even when the temperature remains the same. Since 2015, I have been on the medical staff for the Badwater Ultramarathon, which is held in Death Valley, California, every year in July. During times when the humidity is around 5 to 10 per
unsupported, using buried caches of food and water. The summer monsoon started in that area about three days into our trek and the high humidity at times, along with the high temperatures, made parts of it much more difficult. It is very easy to “feel” the higher humidity when it’s 46°C or more, and much more comfortable at that temperature as the humidity level drops. Dave Heckman Ashland, Oregon, US
Flat about fizz Why does my wife like wine with bubbles more than flat wine? Do the bubbles add to the taste or does her preference come from marketing and cultural context? And why do I not like fizzy wine?
cent, the runners can handle the 49°C temperatures much better than when it gets towards 15 per cent humidity. The medical staff see far more runners with heatrelated problems as the humidity level climbs. In July 2012, my friend Marshall Ulrich and I were the first to circumnavigate Death Valley National Park on foot,
n This is most likely a learned behaviour. Laboratory animals won’t drink carbonated liquid, and people adjust to the feel of it (or don’t) in the same way as they do to the bitterness of coffee or to spicy food. Surprisingly, the bite you feel from the fizz doesn’t come from the bubbles popping. When scientists got people to drink carbonated water in a hyperbaric chamber – where bubbles couldn’t form but the carbon dioxide was still present in the liquid – subjects reported the same sensation. Instead, it comes from a sour receptor called TRPA1, which is activated by carbonic
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. New Scientist 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.
“Medical staff see far more runners with heat-related problems as the humidity level climbs”
acid. A protein in your mouth called carbonic anhydrase converts the carbon dioxide to this acid, and the TRPA1 receptor detects this. At high acid levels your body goes into “get it out” mode and you will start coughing, choking and tearing up. But at low levels, the fizzy burn is pleasant for many people. The acid also makes sweet things taste less sweet – just consider how much sugar is hidden in one glass of cola. So the carbon dioxide changes the taste too. The same scientists found that once the acid sensation is present, injecting bubbles around the tongue enhances the feeling –
“Laboratory animals won’t drink carbonated liquid, and humans adjust to the feel of it (or don’t)” even if the bubbles are just plain air. The mechanism for this is unknown. So, if you don’t like fizzy wine, the most likely reason is you probably prefer sweetness or you don’t find the acid bite pleasant. Ron Dippold San Diego, California, US
This week’s questions SHADOW OF A DOUBT
Sitting outside with my back to the sun, I noticed that the shadow cast by the clear lens of my glasses
was equally as dark as that cast by the frame and my head. Why? Surely the clear lens would let the light through rather than casting a shadow? Richard Batho Jersey, Channel Islands I SPY EWE
After I released a lamb that had got its head stuck in a fence, it ran halfway across the field to a ewe and immediately started suckling. I heard no calling, so how did the lamb recognise its mother from all the other ewes it ran past? It can hardly have been the coat she was wearing. Gillian Coates Trefor, Anglesey, UK HAIR OF THE DOG?
I’ve watched TV documentaries that show people’s pets receiving chemotherapy. It doesn’t seem to cause them to lose their fur or hair, unlike humans. Why? Ann Wills London, UK STING IN THE TAIL
Mosquito bites frequently induce a sharp sting in people and some animals, with severe evolutionary consequences for the mosquito when it gets swatted. Are any mosquitoes evolving with delayed-action stings or reduced sting secretions so they can drink blood without the threat of imminent death? Clive Wilkinson Reef and Rainforest Research Centre Townsville, Queensland, Australia