Snails, planets and chocolate!

Adam Murphy and Chris Smith introduce the panel...

Chris - Welcome to the stage Giles Yeo! Giles is a geneticist; he's also an author. You occasionally see him pop up on the BBC. And actually we were doing an event together a few years back and Giles said to me, "I've gone vegan Chris for an experiment for the BBC." And I said, "how's it working out?" He said, "very windy."

Giles - Pardon me! People that haven't had dinner yet. Or maybe you have had dinner. Hello.

Adam - Well speaking of dinner, we also have Cambridge University chemist, advisor to the chefs, chocolate designer, an expert on all things that are very, very small scale; please welcome to the stage Ljiljana Fruk.

Ljiljana - Thank you. Hello, hello!

Chris - We always end up talking about restaurants as well because you're not just a chemist or a chemical engineer, you're a bit good at food.

Ljiljana - I know. I like eating, so I thought maybe I'll turn my science into something good: experiments that can be eaten later on. And so I ended up mixing up the chocolate! And you can imagine... I perfected the recipes for two years, you can imagine how enjoyable that was.

Chris - Also with us: volcano expert and professor of planetary geoscience at the Open University, David Rothery! It's traditional to ask people who know about planets: what is your favourite planet? Is it Uranus?

David - No, it's not. It's Mercury because we have our own spacecraft on its way to Mercury as we speak. And you've helped pay for it, so thank you very much. It's called BepiColombo, it's a European Space Agency mission joint with the Japanese Space Agency.

Chris - And what's it going to do?

David - It's going to go to Mercury, split into two spacecraft - the European one and the Japanese one - orbit the planet, but it won't get there until round about Christmas 2025.

Chris - Wow, that's a long... it's not that far to Mercury though, is it? Why so long?

David - We set off away from the earth...

Chris - Well, that was a mistake, wasn't it?

David - Well no, because it's rocket science. We're swinging back past the earth next month. That swings us in towards the sun. We have two flybys of Venus; that swings us in past Mercury, but we're going too fast to get into orbit, so we fly past... go round the sun, flying past Mercury six or seven times, slowing down each time thanks to Mercury's gravity grabbing hold of our spacecraft a little bit. And the last time we approach Mercury, we're sneaking up on it slowly enough to get into orbit.

Chris - Why didn't you just fly a bit slower in the first place?

David - You can't, because you're falling towards the sun all the way. So our ion drive, which is what propels us, is actually acting as brakes to slow us down all the time. And we can't carry enough fuel to screech to a halt if we want to carry instruments on board the spacecraft, which we do because we want to find out what the planet's like when we get there. So you have to play these patient games in space.

Adam - Wow. And last but not least, we have beetle enthusiast and expert on woodlice personalities: please welcome to the stage, a tank. I mean Eleanor Drinkwater!

Chris - Now Giles, we mentioned and alluded to the fact you do programs on the BBC as well. There must've been some times doing that when some funny things happened.

Giles - Probably more for people watching me than for me, the one lesson: always read the waiver form. Just the fact there's a waiver is an issue. So I did an experiment for Trust Me I'm a Doctor for what happens to your glucose levels, your blood sugar levels, when you get stressed. So for a week I was wandering around with one of these glucose patches, you can actually do continuous blood glucose monitoring, and we were just figuring out what happened to my glucose after I ate. And so we then showed up on the experiment day, we had all this data, five days of what happened after I ate to my blood glucose levels. I ate; I looked at the waiver, which I didn't look at before; I signed it; it said pain in there somewhere, this is always a bad thing. And then I showed up in a room and there was a water bath at two degrees Celsius.

So I walked in and there was a po-face, white-coated gentleman in front of me, and he said, "stick your hand in in the water." Remember there's cameras on me, okay. So I stuck my hand in the water, and because the camera was on me and there's children here, I nearly swore, but I didn't. It felt like my hand got chopped off. And so 90 seconds later I then pulled my hand out and the guy goes, "subtract 37 from 1,889 sequentially!" So I'm sitting there with my hand falling off, trying to make the decision, and he yells at me for being slow, for shaking my leg...  "Hand back in! Hand out! Hand in! Hand out!" Very stressful. But what was really interesting was what happened to my glucose levels. So normally when you eat your blood glucose levels go up, and then they come back down again as long as you don't have diabetes, and I don't have diabetes. But what was interesting was as they went up after I ate and were coming back down, the moment I stuck my hand into that ice cold water, okay - the moment I got stressed - my blood glucose levels came to a screeching halt. It took nearly two hours to go down to what it was at fasting. Why? Because when you're stressed, suddenly you're thinking, "tiger, tiger, tiger," right. And so your body then keeps the glucose levels in your blood so that you have fuel to run from the tiger, to hit someone, whatever you're supposed to do, biology at work. I knew it because I study it, but it was very interesting to see.

Chris - Eleanor?

Eleanor - I can't understand how someone managed to talk you into this. You're probably one of the smartest people I've ever met.

Giles - I didn't read the waiver. Oh! But the other thing was, they couldn't tell me what the stress was, to make sure I was super stressed. I think that's probably the... I didn't actually know what I was walking into.

Adam - Now Ljiljana, as we mentioned, you are a chocolate designer. How does an engineer at the tiny scales start working in chocolate?

Ljiljana - Yeah. As I said at the beginning, I really wanted to do some chemistry where you have a result that is really desirable to other people! Because chemistry has sometimes such a bad reputation, that we are doing bad things. And I thought let me a souvenir that people can take with them, eat it, and then learn about the molecules. So we designed molecular chocolates. And it seems to be working. People are coming to me and asking me about dopamine, and glucose, and ethanol; all of these molecules that we embedded within our chocolate...

Chris - Yeah, the last one of those I can definitely identify.

Ljiljana - Yes!

Chris - Because of course that is, for people who are not in the know, that is alcohol.

Ljiljana - I know!

Adam - David?

David - So chocolate is a long chain carbon molecule basically, yeah? There's something that forms in the atmosphere of Pluto and settles to the ground and stains Pluto brown, which we think is a kind of hydrocarbon. Do you think it's possibly worth going to have a lick?

Ljiljana - I think we should name it together!

Chris - It is in the Milky Way...

All - Uuugh!

David - Other chocolate bars are available.

Chris - As someone who has been working... because you work with the BBC quite a bit as well...

David - Yeah.

Chris - Have you got any interesting things to relate?

David - You want me to tell you about fun and games with Brian Cox on the Planets series? There was an Open University coproduction called The Planets, which aired about 10 months ago, and two of us at the Open University, planetary scientists, were consultants. And we would get drafts of the scripts and tell them what was wrong with it, and how to put it right. This is a production company, and then it would go to Brian Cox, and he'd go off in a glider over the Alps or on some glacier in Iceland, somewhere atmospheric to do his pieces to camera. And he often went off-script on those, so we couldn't really control what he said. But he knows his stuff by and large... He's a particle physicist rather than a planetary scientist. But he did a lovely piece with an iPad on a glacier in Iceland saying, "look at this picture of Uranus - your favourite planet, Chris - with these rings..."

Chris - No comment.

David - "...and two little moons, one outside the ring, one inside." These were shepherd moons. And the thing about very narrow rings, which Uranus has, is that the moon orbiting inside and outside help keep that ring really narrow and keep it in shape, they're called shepherd moons. And Brian was explaining very eloquently how the outer moon going a little bit faster tugs the rings upwards, and the inner moon going a bit slower tugs the rings downwards, and between them that keeps the ring in shape. And it was very persuasive, very well done. He talks to camera beautifully. And when I saw the rush for this, the recording that comes for approval, I thought, "that's great, he's done well. It's not what we planned, but it came over really well." And it was broadcast. And the people on Twitter were saying, "that was wrong!" Because the inner ones go faster than the outer ones. Anything orbiting something, the closer you are, the faster you go. So you've got the principle right, of the tugs in opposite directions keeping the rings tight, he just got the relative speeds wrong.

Chris - And you didn't read the small print then?

David - I was seduced by Brian's brilliant delivery, but people watching television spotted it, they tweeted, and I said, "oh yes, we got it wrong!" And then Brian tweeted saying, "yes, sorry, I've got it wrong." And it's even more stupid because I did a Masters project on these very shepherd moons doing this. But when you're telling a story, it's very easy to just tell it the wrong way round. You concentrate on explaining the opposing forces doing a good job, and you can get something fundamentally wrong and not realise it.

Chris - That's why your space probe's going to take 15 million years to get to Mercury!

Giles - I did exactly the same thing once, where literally it was a graph. Now this isn't even complex. It wasn't moving, it was just a graph with a blue line going up, a red line going down. And I said, look at the red line going up. It went all the way, except for one thing: they ended up catching it the night before it went out. I had to rush down to a studio - actually came to the Naked Scientists studio actually - in order to record one line. And that's just: "just say down! Just say down!" I went, "down." And they spliced that down in, and I said it correctly.

Chris - Now Eleanor, you come on the Naked Scientists quite often because you are our insect guest, you're our creepy crawly expert.

Eleanor - Right, thank you.

Chris - And you agreed kindly - because you've come back, and we're delighted you're back in Cambridge - and you have brought us a surprise.

Eleanor - Yes, I have. So whenever I talk about science, one of the things I'm really keen about is trying to get people to realise how brilliant invertebrates are. And so I thought the best way to do this was to bring along a guest. This is Shellock Holmes.

Chris - Did you say 'Shellock' Holmes?

Eleanor - Yep, Shellock Holmes. It's too funny. So Shellock Holmes is a East African land snail. Whoops! Thank you.

Chris - 'Was' an East African land snail...

Eleanor - No that wasn't him, it's fine. Here we go, I'll just see if you can see him a bit better if I move away some of his salad.

Adam - He's got quite a banquet there.

Giles - I know...

Eleanor - Yeah, exactly.

Chris - No wonder it's so big!

Eleanor - Exactly, yeah! So when he's fully spread out he gets to about 18 centimetres long. And the really, really crazy thing about this species is they reach that size in about a year. So that means they have this incredible need to try and find as much calcium as they can. So in the wild you'll find them scavenging for bones of dead animals in order to try and get as much calcium as they possibly can. Or sometimes concrete, they'll go for a little bit of concrete as well.

Ljiljana - So they are taking this calcium from the bones, which means they probably have some kind of chemicals in their slime that can dissolve this bone structure?

Eleanor - I don't know exactly how they do it.

Giles - Because they don't have teeth...

Eleanor - But they have these lovely mouthparts though. When you watch them eat, they've kind of got this... it's almost like a kind of, you'll see it like a little pumice stone, kind of scratching off the layers. And one of the other lovely things about this is: so in the wild, they tend to be a lovely dark gray-brown colour; well this one's albino. And so as a result you can actually see, when he eats, you get little globules of food that you can see coming through its skin, because the skin is actually transparent. Which is another reason why... yeah! They are just amazing.

Chris - Good job that doesn't happen to humans. So tell me Eleanor, I'm intrigued, does a fat big snail like that travel at the same speed as a small one? Or is there a speed advantage with a big snail?

Eleanor - Ooh. That is a very good question. I would have to say that I don't know, but I do know that snails aren't known for their speeding ability.

Chris - Yeah. Well you see I've got a vested interest, because I was taking part in a snail race the other day. And we were all racing snails.

David - Did you win?

Chris - And mine was going really slowly. And so I said, "should I take the shell off?" Because I thought that would lighten the weight. And the person who was with me said, "no, that'll make it more sluggish."

All - Uuugh!

Eleanor - I see what you did there.

Chris - Give them all a round of applause, everybody! Our wonderful panel for this evening.