Ben - This is the very last Naked Scientists show of 2009. So we thought weíd look back on a few of your favourite bits. Itís been a great year. Weíve had some very interesting guests, been to some incredible places, and done some fantastic experiments. But first, Helen, whatís been some of your favourite bits?
Helen - Oh, well thereís so much to choose from. But I think something that stood out for me was when we had Dr. David Aldridge in the studio from Cambridge University. And he brought with him some creatures found in freshwaters around the world that really shouldnít be where we find them. So this was all about the science of invasive species. And he brought some critters for us to look at.
Ben - And we can have a listen to that nowÖ
David - Iíve got a little menagerie of goodies here. And Iíve got some zebra mussels. Iíve got a signal crayfish from North America. And Iíve got a Chinese mitten crab. Theyíre beautiful. But unlike our native freshwater mussels which just sit in the bottom of rivers with their foot being into the mud, zebra mussels have a beard, a bit of thread which is like the marine mussels that you eat. So zebra mussels are able to sit on solid surfaces. And they can attach to each other and sit in dense layers. So they can foul pipelines and drinking water supplies, cooling systems to power plants, irrigation systems. But also they sit on our native wildlife and one of the things they really threaten, such as a specimen Iíve got in front of me, are our native mussels which provide a really good substrate and they choke them and cause them to die.
Helen - Thatís a huge mussel youíve got there. And I can hardly see it. Itís been covered in smaller zebra mussels. Thatís incredible. And the Cray fish you got there, that looks quite tasty. Can we eat those?
David - We can. And thatís the reason they were brought over here. The American signal crayfish was brought over in the 1970s as a commercial aquaculture food. The problem with these crayfish is that they can walk over land so they escaped out of these little ponds they were put in. And they can move into the wider environment, so they are very good at changing the ecosystem through feeding on the bottom rooting plants, the macrophytes. And they dig burrows, which can cause sort of destabilisation of the banks. But perhaps of greatest of immediate concern is that they carry a fungus, something called crayfish plague, which kills our native crayfish species, but these American ones are pretty resistant to it. So weíve had, for instance, in the Cam in 2000, an outbreak of plague which wiped out native crayfish from about 20 kilometres of river.
Helen - That was Dr. David Aldridge telling us about some of the creatures that get into freshwater bodies and cause trouble where they shouldnít be. And we had a look at some of them in the studio. And that was quite fun. That was great.
Ben - Itís very nice to have our own innovation of invasive species. Itís not often people bring things into the studio.
Helen - I think we should do that more often. And thatís what we should do in 2010, is bring creatures into the radio studio. Is that alright with everyone else?
Ben - Well we do have a cooked chicken with us . But I think thatís a slightly different way of thinking about these. Now, speaking of species that we donít want around, there was also a lovely new story from earlier in the year about the love song of the mosquito. Now if you listen very carefully to this, you could almost hear Dr Kat squirming in her seat.
Chris - Now have a listen to thisÖ That is a male mosquito buzzing its wings at something like 600 hertz, 600 times a second.
Now have a listen to the female mosquito; these are Aedes aegypti mosquitoes. Here we goÖ
Now I wonít subject you to too much more because Dr Kat has got her fingers in her ears but thatís at about 400 hertz.
But if you do what two researchers at Cornell did, thatís Lauren Cater and Ben Arthur, they put one of those mosquitoes tethered to a pin with a piece of superglue to keep it in one place. Then they bring in a mosquito of the opposite sex and record what happens to the wings of the two. Have a listen to thisÖ
And whatís actually happening is that the two mosquitoes are adapting the beating frequency of their wings so that they harmonise.
Ben - Isnít that lovely, mosquitoes singing in harmony? And Iíve never seen such a visceral reaction as Kat squirming in her seat like that. But fair enough itís a horrible sound, the sound of mosquitoes. But I thinking of something a bit more pleasant. Weíve had loads of great experiments in Kitchen Science.
I remember at the start of the year, we made some jelly to show how fruit enzymes can cut up proteins and stop the jelly from setting. Although I think it may have just been an excuse to make lots and lots of jelly. But, Dave, what else have you really enjoyed this year?
Dave - There are all sorts of things this year. Ranging from videoing popcorn popping, watching they way... Itís absolutely beautiful the way it unravels because itís a really strong pressure vessel, you get it really hot and the water inside boils. The pressure builds up and it breaks. And it opens itself up almost all the way. So I got a few minor oil burns from that one - itís not something you really want to try at home.
We did all sorts of lovely things which I keep bringing out at dinner parties as well. Thereís one which I found from a guy I met at the British Interactive Group. You just have a nut on one end of a piece of string and a mug on the other end, hold it over a pencil and just let go of the nut. Despite what youíd expect, every time as long as you donít mess-up too badly, the nut runs wraps itself around the pencil and it doesnít hit the ground.
I also had one which actually got a proposal of marriage from my housemate which my girlfriend wasnít entirely impressed with, which was getting an orange peel, an especially good juicy orange peel and squeezing it next to a candle. You get these huge fireballs, maybe five or six inches across. Itís absolutely beautiful especially in slow motion as well.
Helen - Thatís very cool. I like that one too, actually. But another one that sticks on my mind especially was when you soaked me in the studio. I thought that was rather mean. But it was great fun. And I think weíve got a clip from that one coming upÖ
Dave - So if you spin that nice and quicklyÖ
Helen - Do I let go of it or do I try to hold on to it?
Dave - Just keep holding it and spinning it nice and quickly.
Helen - In one direction?
Dave - In one direction.
Helen - Oh! Oh I see. I see.
chris - That was fantastic.
Helen - Iím covered in water. And thatís the last time I offer. So what happened is the waters flew out of the open ends of the straw. Iíd have another go but I think I might get the microphone wet.
Dave - Yeah, we should be careful.
Chris - That was really good.
Helen - It was awfully but rather a beautiful fountain for a moment there.
Ben - Well, clearly that tickled Dr Chris. Dave, did you know that was going to happen?
Dave - Iím afraid that fairly simple physics made it pretty inevitable that that was going to happen.
Helen - Ooh, Iím shaking my fist. Oh well, anything in the name of The Naked Scientists, thatís fine.
Ben - Of course. And we didnít get any microphones wet, not at all. We do never do anything that could in any way harm any of the equipment in the studio. We wouldnít dream of it.
Now Iíve really enjoyed meeting some of the people Iíve interviewed this year. I spoke to science minister Lord Drayson about why science is so important. But a bit more fun was talking to comedian Robin Ince about how science and comedy are very closely linked.
Robin - What is happening is thereís a huge, an accidental rational movement basically. I think after we put together the show Nine lessons and carols for Godless people where we, on the science side, you had Simon Singh, Ben Goldacre, Richard Dawkins, then various musicians people like Jarvis Cocker and Darren Hayman, and then comedians. And all of them are doing something on the rational world. And you have people like Dara OĎBrien, Chris Addison, Stewart Lee and Josie Long, all of them are approaching things from a rational spectrum. Especially Dara who has a physics background. Heís very excited about talking about science. And I think that perhaps, I donít know, but perhaps TV isnít really pandering very much to intellectual programming. So I think there has been an accidental rational/scientific movement start in comedy.
Dave - And weíve also been to some amazing places this year. Laura Soul climbed to Everest base camp and reported back on how her body reacted to the low levels of oxygen. It clearly wore her out somewhatÖ
Laura - Yes. Itís good to sit down. I have a bad headache and so do most people. I felt a bit sick on the way but Iím OK now. Some people feel very sick. The view from here is absolutely amazing. You can see the Khumbu ice fall which is really beautiful with these huge big jagged peaks of ice. Itís been a very hard route to get up here. But Iíd say that it was definitely worth the climb.
Helen - I think you can just about feel kind of just how exhausted she is. Itís amazing. Well, I was rather, well I was a little bit envious, I have to say, of Meeraís trip to South Africa this year and when she got to meet some cheetahs. How lovelyÖ
John OĎBrian - Somewhere very nearby here is a cheetah on a kudu killÖthere we go...
Meera - Oh my God! Yeah. Uh-oh. It spotted us. Does that matter?
John OĎBrian - Oh, no, no, no. Theyíre very relaxed. Theyíre feeding so itís got other things on its mind. And cheetahs arenít, animals that are dangerous or anything to humans.
Meera - So weíve parked up alongside this tree. And I can just see the cheetahís body and its head, and oh, its tails wagging now. It is just quite literally having a feast down there, munching away.
Ben - You can hear how excited she is by that little gasp of breath. Really excited to hear that. Itís also quite nice to know that cheetahs are quite a bit like my cats at home and that once you gave them some food, they donít care about anything else whatsoever.