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Kitchen Science
Make a flame jump several centimetres using just a humble candle.
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Question of the Week
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If the speed of light is slower in glass than in air, where does the energy come from to speed it up as it exits the glass into air?
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Questions

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Are spiders web edible? As they're made of protein.
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Spiders do eat their webs. Sometimes they eat them everyday to try and get back in some of the energy they've expended on it. Another interesting use of spider webs is that they've got quite a lot of a vitamin K in them which can help your blood to clot, and before the use of gauze, people used to put spider webs on wounds. People are currently looking into what makes spider webs so strong, with hope to make this artificially, they would make great bullet-proof vests. They've found the proteins in them that makes them strong, called Spidroin 1 and 2, and you can produce these in the lab. But they have to use insect cells to grow it, because the insect cells do some chemical modification and insects are more closely related to spiders. They're not at the point where you can scale it up to a bullet-proof vest yet, but its certainly interesting.
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If our skin is always regenerating, why do we get wrinkles?
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It’s probably because your skin’s regenerating as you have cells in the top layer of your skin or epidermis that are constantly multiplying to replace the skin that dies but the bit that holds the structure of your skin at a lower level is called the dermis and that contains a molecule called elastin which breaks down as you get older. You also lose the fat in the lower layers of your skin. So although the top layer of your skin is regenerating it’s the bottom layer that’s going saggy and makes you wrinkly.
And if you smoke, the chemicals in cigarette smoke also encourage that break-down to accelerate which is why people tend to get a lot of wrinkles around their mouth if they smoke. A good way to anti-age yourself is to stop smoking and stop going on sunbeds as well.
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Why is it recommended to put salt on cuts? It seems to be popular advice with dealing with cuts on the inside of your mouth, for example, but what’s really happening and is using salt actually a good idea?
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A lot of bacteria, especially the ones that cause ones in the mouth are bacteria like streptococci, and some of the other mouth-dwelling organisms and they’re quite salt-sensitive. When you put a big dose of salt on them the salt is a bit like putting salt on a slug. It pulls the water out of the bacteria and dehydrates them and can damage them. Other bacteria though like staphylococcus (aureus) actually like salt so if you have a wound on your finger it might not actually be so good for that because it will kill the bugs in there which are not staphs but it might end up with your being colonized entirely by staphs. It’s quite good in very high concentrations it stops bugs growing. The likelihood of you getting enough concentration of salt on the wounded area to kill the bugs is quite unlikely. It does have a soothing effect though.
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Why, if you’re standing in a doorway and you push you arms against the door for about 30-40 seconds and then step out, your arms go ‘woo’ up in the air? What’s going on?
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This is to do with the way in which your muscles control their length because hidden inside each of our muscles is a tiny thing called a muscle spindle and this is like a miniature muscle which has nerve fibres in it and those nerve fibres can tell how much the muscle is being stretched or lengthened. When you put force through a muscle it’s trying to register, ‘how hard should I contract, am I contracting at the right rate?’ If the muscle is contacting hard but not going anywhere then this spindle doesn’t stretch and it keeps sending messages back to the muscle saying you’re not getting any longer, work harder. So when you’re pushing up against the wall and your arm isn’t going anywhere , it’s trying to contract harder and harder to move the wall which, of course, doesn’t move. Then when you move away from the wall and you switch off the voluntary drive to the muscle the spindle is still set to say I’m too short, I need to be longer. It tells your nervous system automatically like a reflex to make your arms longer.
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Why does opening a car window on a hot day when the car is running feel much cooler than opening it when the car is at rest?
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This is the wind chill factor and the answer to this is a bit like saying ‘I’ll turn the fan on.’ Does it make a room colder? A fan running does not cool a room. A running fan keeps the room at the same temperature it just moves more air past you. Air molecules, when they’re run past you if you’re sweating and hot, each molecule can take a little bit of heat away from your skin so the more molecules that pass your skin the more heat you can lose. It makes you feel cooler but it doesn’t actually affect the temperature and that’s why when you’re driving along nice and fast with your window down lots of air molecules running over you cools you down.
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Why are there apes in the zoo? Why does one ape decide, ‘I fancy being a man,’ and another genus of ape says, ‘I’m quite happy being an ape'?
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Essentially, all of the apes have evolved separately. We separated from chimpanzees somewhere about 5 million years ago and we’ve all evolved in our own different ways since then. It’s quite an interesting question that why are some in the zoo and others aren’t and I guess that doesn’t say much about us as a species. If we found a hobbit today and put that in the zoo it would be quite an interesting one. But it’s not just evolution by anatomy as well. There’s research showing that some groups of chimpanzees in Africa have actually developed the use of stone tools several thousand years ago. So there’s a stone tool age for chimps.
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| In Search of Eden: The Origin of Man - More about this podcastAre we there yet?
This week on the Naked Scientists we’re taking the ultimate road trip – following the spread of humans across the globe. We’re joined by Jenny Collier to discuss how an enormous flood cut Britain off from Europe, sparking thousands of years of jokes and grudges in the process. Chris Turney will be here to explain how you date a Hobbit, using radiocarbon rather than romantic means.
We’ll also be looking at the history of fire, discussing recent evidence that early man could have kept his toes warm at the hearth 1.5 million years ago. Meanwhile here in the present day, Kitchen Scientists Ben and Dave have a go at making fire the old-fashioned way.
Mega-flood warning
Although it’s hard to believe nowadays, Britain used to be part of the land mass of Europe, and our ancestors could walk over to France with ease for a spot of hunting and gathering. But some time between 450,000 and 200,000 years ago, a mega-flood changed all that.
The flood is thought to be the result of an enormous lake in what is now the North Sea bursting through an ice dam and rushing across the continent. At its peak, the flood discharged around one million cubic metres of water per second, and resulted in major rivers such as the Thames and the Rhine being re-routed. Dr Jenny Collier is from Imperial College, London, and we’ll be talking to her about the giant flood that shaped the geography – and subsequent history – of our island nation.
Dating a Hobbit
Homo floresiensis – affectionately known as “the Hobbit” – hit the headlines a few years ago when scientists found remains of these diminutive hominids on the Indonesian island of Flores. Here at the Naked Scientists we wondered if they could be the ancestors of our own Dr Kat, who’s more than a little on the short side. But since their discovery a scientific storm has raged about the specimens. Are they a pygmy version of modern humans, or an entirely separate species? Or maybe they had a syndrome called microcephaly (small heads)?
To help us get to the bottom of this evolutionary mystery, we’re joined by Dr Chris Turney from the University of Exeter. He was responsible for radiodating the specimens, and he’ll be telling us how he’s using the latest developments in technology to pin dates on some of the sites where key hominid fossils have been found.
Twisted firestarters
The controlled use of fire was a vital step in the progress of humans from the grunting creatures of a million years ago to the grunting creatures of today. Until recently, the oldest known use of fire by man was thought to be around 400,000 years ago, at a site in China. But new research has turned up evidence of fire use in South Africa dating back 1.5 million years. We’ll be finding out how complex scientific analysis has revealed that these are likely to be genuine campfires, rather than accidental brush fires. And does it mean we have to rewrite our theories about the evolution of the human brain?
Finally, in this week’s Kitchen Science, Ben Valsler and Dave Ansell attempt to make fire the old fashioned way – using flint. Well, we always thought they were a bit primitive…
Kat Arney |
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