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3rd Feb 2008
Wet and Wild
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Get Wet and Wild with the Naked Scientists! We don our wellies and wade into the science of wetlands, discovering the species you might see and why wetlands are vital for wildlife on land and at sea. We'll also find out how wetlands protect us from floods, and what can be done to conserve them in the face of climate change. Also in this weeks show, how Humans are fatally infecting Chimps with the common cold, the culture of a chameleon's colours and onions that can't make you cry! Plus, in Kitchen Science we hear the radio signal from a remote control, and find out how you can answer your mobile phone before it even starts ringing!
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News
Recent research carried out in West Africa has shown that humans are fatally infecting chimpanzees with our common cold viruses.
Primatologist Sophie Kondgen, from the Robert Koch Institute in Berlin, examined clinical samples collected during from ill chimpanzees during respiratory disease outbrea...
Something that we all know about the natural world is how the colourful chameleons are masters of disguise changing the way they look to blend perfectly with their surroundings, hiding away from would-be predators that they are too slow to run away from.And we might expect that the need to camouflag...
Scientists in New Zealand have used GM technology to develop onions that can't make you cry.
Working with colleagues in Japan, Colin Eady, who is based at New Zealand Crop & Food Research, has successfully silenced the gene responsible for producing the lacrimatory (tear-jerking) factor, which ...
Today’s programme is about wetlands, so I’m going to get the ball rolling with a piece of science news from Canada. If I was to ask you to think of an aquatic animal that has the ability to change its environment and alter the course of streams and rivers, you would most probably come up with the da...
Kitchen Science
You know you can use your remote control to save you the immense effort of getting out of your chair, but did you know you could make strange noises from it and a radio?
QotW
How is oxygen made and recycled on the International Space Station?
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Interviews
Could something in your diet affect your emotions? Rising Star Caroline Stokes explains how you could eat your way out of depression...
The Barnes wetlands site in London lays claim to be the 'best urban site in Europe to watch wildlife, and is home to rare and beautiful wildlife including Bitterns, Kingfishers, a colony of endangered Water voles and this week, Naked Scientist Meera Senthilingam...
The Louisiana wetlands are the largest in the USA and amongst the largest wetlands in the world, playing a vital role in keeping the sea, and local wildlife healthy. We spoke to Robinson Fulweiler from Louisiana State University...
despite being expanses of waterlogged land, wetlands actually offer great protection against flooding. So good, in fact, that the UK's Environment Agency are generating new wetlands for just this purpose, as part of the Alkborough Flood Protection Scheme...
Wetlands are disappearing faster than rainforests, and support a huge number of species as well as offering protection from flood and filtering out water before it reaches the sea. So what can we do to conserve them?
Questions
How many watts is a burning candle?
We had an answer on our forum from Bored Chemist. He assured us the original standard candle will burn a waxy substance called spermaceti. It’s called that because it comes from sperm whales. The best that we have today is, of course, petroleum based wax. We’ve got to compare for that. But the standard candle, he says, would burn 120 grains of spermaceti an hour. That’s 8g.
Bored Chemist worked out for us that this means that it burns 2.16mg or about 2 thousandths of a gram of spermaceti every second. If we know how much energy is in a gram of this stuff we can work out its wattage which is essentially energy per second of the candle. Assuming that spermaceti is similar to a typical type of fat or oil we can see that it gets about 37kj per gram. The candle was burning 2 thousandths of a gram each second which gives us a power of about 80 watts.
The reason it isn’t as bright as an 80W light bulb is because it’s really inefficient. Most of that 80W is actually given out as heat. So it’s not like the energy efficient lightbulbs. Most of the stuff coming off candles is heat with only 0.05% of it, not very much at all, coming out as light.
Do fish always swim anticlockwise in a round bowl?
We were first asked this question in the Naked Scientists Combating Climate Change Show.
Chris: Izzy wrote to me to tell me why she thinks it is. She says, ‘There’s a simple reason why fish swim in circles and not always in the same direction. There’s a current in the bowl. The caller said their fish swam anticlockwise that means that the current in the tank is going clockwise. The fish swim into the current because they get ore oxygen forced into their mouths and through their gills. If the current was going anticlockwise the fish would swim clockwise. If they swam with the current so using less energy to travel they would actually end up worse off because they wouldn’t get enough oxygen to make up for the energy they’re using to swim at all. It’s much more efficient for them to swim into the current. This phenomenon is known as rheotaxis.
Helen: I certainly see fish in the wild swimming into currents. I always though it was so they could stay in the same place because you quite often see flickering away into the current. Why is the current there in the tank in the first place?
Chris: I wrote to her and said that. And surely the fish swimming would make the water move in the same direction as them and she said, ‘My understanding is that when fish swim they push the water behind them in little eddies because nothing’s perfectly efficient in the natural world. The eddies cause a spin and this makes the water travel backwards and also turn in the opposite direction to the fish’s motion. That’s why you then set up a current in the opposite direction to the fish.
Helen: Sounds a bit like fish and egg to me. What came first?
Chris: I think people have to put it into perspective. Often people have bubblers in the tanks and a bubbler means the bubbles rise asymmetrically up the tank and this pushes the water round in circles. I think she’s hit the nail on the head that the fish are going into the current if there is one.
Should you repair a broken dish for food?
Helen: I think if we think about it carefully, it’s got to be true that bacteria can get into those cracks and you can’t reach them there to scrape them off. There’s no physical way of cleaning them out. Bit of water and food can also get into that crack so they can do very nicely, thank you very much, they're safe, they have water to keep themselves going and food. Yes, whether or not it’s going to actually have a big effect I don’t know. I still drink cups of tea with cracks in and I haven’t yet caught anything nasty. Maybe if you’re worried about it then yes, don’t go there.
Chris: I think she’s right because you’re going to have a bacterial banquet down there. You’ve got food and water and you can’t physically remove the bugs. They could actually be growing in there and then contaminate food. If you, for instance put food on the plate and then store it for a period of time it could contaminate the food. Especially if you put warm food on bacteria grow very, very fast.
Where does the bacteria in our gut come from?
It will probably surprise you to learn that we’re actually passengers in our own body.
If you count the number of bacteria that live on us an in us there are roughly 50 times as many of them as there are cells in our entire bodies. There are roughly ten thousand trillion cells in humans so that’s a lot of bacteria.
Where do they come from? Well, the answer is when a baby first pops out, assuming it comes the normal way, its first taste of life is quite literally a mouthful of muck. It’s its mums muck. It’s bacteria and other debris that are all over the pelvic floor and perineum of the mother. When the baby comes out those bugs that are there on the mum go into the baby and they get washed down into the stomach and then into the intestine where they take root.
The reason babies can do that and in us most bacteria get killed is because babies don’t have much stomach acid at that stage so the bacteria can very easily get in and settle down into the gut. After a few years they develop and turn into a very unique spectrum which is almost as unique to you as your fingerprint is. If you come out via a different route, say you have a caesarean then the kinds of bacteria that a baby picks up will be different and that’s been demonstrated.
Because of the spectrum of bacteria being a bit different there can be consequences for your risk of future diseases including things like getting allergies and also having bouts of diarrhoea. Recent studies have shown that babies born by caesarean section are actually twice as likely in their first year of life to have doses of diarrhoea and to have allergic reactions to things. Coming out the right way and getting a mouthful of muck unless you absolutely have to come out the wrong way is probably the best way.
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