Printer ink - the most expensive liquid?

Our expert panel  - Giles Yeo, Clare Bryant, James Rudd and Fran Chadha-Day - take on some fiendish quiz questions...

Chris - So James and Fran, you are going to be team one, and Clare and Giles, you are going to be team two. Round one is called scientific “oops”. So team one, that's James and Fran.

In the 1950's Noah McVicker and his brother, they worked at a soap company where they invented a clay based product that was for cleaning wallpaper to get the soot stains from cigarettes and coal-fired powers off of the walls, but the invention of wipe clean wallpaper unfortunately threatened to put pay to their invention until a nursery school teacher pointed out its potential and they turned it into. What do you think the answer is?

Fran - Well maybe it's something like Play-Doh?

James - I was going to say something like a whiteboard cleaner? Play-Doh is a good idea as well though. Nursery school 1950's. Yeah probably right, I reckon Play-Doh.

Chris - It is, very well done. It was indeed Play-Doh. Unfortunately, vinyl wallpaper threatened their industry, so they had to think outside the box and they took the soap out, put some colour in. The secret to the recipe remains intact. No one knows how they make it or how they give it that lovely smell, because I guarantee if I say Play-Doh, everyone can smell it. You can all smell it.

Fran - Definitely

Chris - You're all thinking of it.

James - Evocative.

Chris - Okay, well done. Well done to James and Fran. One point. Okay, Claire and Giles, it's your turn. Which of these inventions was not an accident? Laser pointers, microwave ovens or safety glass? What do you think?

Clare - Oh, what do you think?

Giles - I think it's going to be something like the safety glass. I bet you that was, that was done entirely, was not by accident.

Chris - Which one of these inventions was not an accident?

Clare - Yeah, yeah I kind of think...

Giles - I would go with safety glass.

Clare - Yeah. Safety glass. We are going with safety glass.

Chris - No, actually it's the laser pointer.

Clare - Interesting.

Chris - Microwaves turned up when, you might know the fairly famous story actually, the scientists noticed, he was working on radar and he had a microwave generator, a magnetron, on the desk in front of him. He had a chocolate bar in his pocket, and when he went to eat his chocolate bar it turned all gooey and realised that there was something coming out of this magnetron, which he was using for his radar experiments, which was very well absorbed.

Giles - That was microwaving him.

Chris - That was microwaving him but more importantly, microwaving and melting the chocolate bar. So the microwave was directly informed accidentally by that experiment. The other one was safety glass, which you chose and actually safety glass was a scientific accident. Someone dropped a whole beaker that they were working on, which was full of cellulose nitrate. When the beaker hit the ground, it didn't smash. It cracked a bit, but it remained intact. And that's because the inside of the glass had got coated with whatever the cellulose nitrate was doing and then they realised the concept of making safety glasses, which could absorb impacts and not break. The laser pointer wasn't the accident. Right, so that's nul point for you there i'm afraid so far. Round two. Now this is called 'Pound for Pound', this round. Okay, so back to James and Fran. Pound for pound, printer ink is the most expensive liquid in the world. What do you think? True or false?

Fran - What about, like, molten gold or something though?

James - Does it have to be liquid at room temperature?

Chris - Oh, it's not a trick question in that respect. No, it's a liquid.

Fran - Or something like liquid helium?

James - Yeah. I have bought some printer ink recently and it is frighteningly expensive.

Chris - Set you back a bit?

Fran - Yeah. I mean maybe there's something in the pound for pound. Yeah, my instinct is that it's false, but I'm not 100% sure. Like, maybe there's just not much printer ink in the thing that you buy, so it's ends up being. What do you think?

James - It's only a few mills I think, per cartridge. So i'd say yes. It's such a ridiculous question, it must be true.

Fran - Okay, let's just say true.

Chris - You know what? You're not going to get this. Yes, and Giles is shaking. He's going, yes, yes, in with a chance! But the answer is actually the most expensive liquid is scorpion venom. The death stalker scorpion. The death stalker scorpion is the most dangerous scorpion on the planet. It's venom is also the most expensive liquid on the Earth. It's 6 million pounds per litre. 100 quid will get you a droplet smaller than the grain of sugar.

James - Wow.

Fran - Why do people want to buy it?

Chris - Ah well, you see a lot of these things, Claire would probably tell you, because a lot of these things are neuro-active, because they're very fast acting, they very, very precisely target very specific elements of the nervous system. So, scientists are really interested in them as potential leads for drugs and other therapeutics, and also ways to unpick how the nervous system works. So they're actually very valuable commodities, also other venoms from snakes and so on as well are in demand.

Clare - And of course you need to develop anti-venoms to protect you if you get bitten by one of these things.

Chris - True. Printer ink, since James, you said you're a bit out of pocket recently. You felt the sting of that. Since we're talking about the scorpions. Printer ink, a competitive 3000 pounds a litre, so still exorbitantly expensive.

James - Wow, I am in the wrong business I think.

Chris - Right, so we are level pegging now, almost. Okay. So if you get this right, you can equalise. You ready Giles and Clare? True or false, anti-matter is the most expensive substance on Earth to make?

Clare - What do you think Giles? I've got no idea.

Giles - I've got no idea, can we even make anti-matter? Isn't that an Avengers story line in terms of that?

Clare - The physicist is not helping here, you know, she's just not really supporting is she?

Chris - Do you notice how we divided the teams quite carefully apportioned to the questions?

Giles - Okay. Assuming they can make anti-matter, you probably only get some nano-particle. So I would say let's go with true.

Clare - It's got to be worth a shot.

Chris - You're going to go true.

Giles - Yes.

Chris - All right. You are going true and true is...

Giles - So you can make anti-matter!

Chris - Oh yes. If you go to, well Fran you can probably tell someone, if you go to to Addenbrooke's hospital and have a pet scan, a positron emission tomography scan, you actually are using the effects of anti-matter in order to scan someone. That's correct, would you concur?

Fran - Yeah, absolutely.

Chris - Yup. According to various sources, because it's so difficult to make, the price tag is a hefty 18 billion pounds per gram, but yep, We can make anti-matter. Level pegging, one-all, back to Fran and James. Round three, a question of numbers. Okay, here we go. This will test whether you were paying attention in the head and neck lectures when you were at medical school. James, how many teeth form a complete set of milk teeth in a child? Is it 20, 28 or 30? What do you think Fran and James?

Fran - I just do not know. 20 feels too low - I feel like I remember having more than 20 teeth.

Chris - You have now.

James - Yeah, I think it is 20.

Fran - OK, right, you should know, so we'll go with your answer.

James - Medical school was a long time ago.

Chris - You are right.

Chris - 20 is the number of milk teeth. It did seem surprising, so it was five in each quadrant - so five on the right upper five on the right lower and vice versa. Adults have, do you know how many adults have?

James - 32?

Chris - Yep, adults have 32, assuming the wisdom teeth come through. So your eights are your wisdom teeth. So 32 teeth in total in an adult. So in the lead so far, let's see if you can equalise, over to Giles and Clare. You have got to stay in this just to stay in the game. What's the chance of having twins in a pregnancy? Any twins. Okay, either identical or non-identical and this is a natural pregnancy, It's not assisted conception. Is it one in 75, one in 150, or one in 300?

Clare - Wow.

Giles - This will be have to be a guess, for some reason I remember the number one in 150, but it could be because I was imagining things.

Clare - Well, it's relatively rare isn't it?

Giles - It is relatively rare.

Clare - Yeah. So one in 150 or one in 300?

Giles - Oh goodness.

Clare - You've actually remembered a number, so maybe we should just go with that.

Giles - And if we lose?

Clare - I'll let you off, Giles. It's all right. It's not the end of the world if we lose this quiz.

Chris - So what you choosing?

Giles - One in 150.

Chris - I'm really sorry. It's actually one in 75. It's 1.33% and it's quite interesting. You can remember this because twins, non-identical twins, one in 75; triplets, one in 75 squared times; and identical twins, much rarer still, 0.3% of pregnancies. So you didn't get the point. So I think this week's winners, therefore are James and Fran. Give them a round of applause. You win a prize beyond price. That's this week's Naked Scientists big brain of the week award. So very well done to you. They look a bit miserable that you beat them.