Quiz: from soft stuff to weird weather!

It's time for our famously fiendish Naked Scientists quiz! In it to win it are plant biologist Nadia Radzman and particle physicist Chris Rogers, facing off against bioarchaeologist Emma Pomeroy and virologist Chris Smith. There's everything to play for...

Phil - It's quiz time! It's the part of the show that you've all been waiting for, and our panelists are going to compete for the prize beyond price: that's to be awarded Naked Scientists' Big Brains of the Month. We're going to divide you into Team 1, that's Nadia and Chris Rogers; and you're going to be facing off against Team 2, that's you Emma and Chris Smith. And I hope you're ready, because it's time for Round 1. This round is called Count 'Em Up. Okay, Team 1, here's Question 1. Which do you think there are more of: transistors in the world's largest supercomputer, or bacteria in the average human body?

Chris R - So I can help you with supercomputers because I know it's an exaflop machine - two exaflops, I think they have on the cards at the moment - but I can't help with bacteria.

Nadia - There are a lot of bacteria. I think a portion of the weight of human bodies considerably consists of the bacteria's mass. I would like to say bacteria, but I'm not really sure.

Phil - What do you think? I'm going to have to press you.

Chris R - I'm going to let Nadia suffer!

Nadia - I'm not sure!

Chris R - Because if Nadia chooses, then I can blame her after.

Nadia - And because bacteria divides very, very fast. I would say bacteria...

Phil - So are you saying bacteria?

Nadia - Well transistors cannot divide, right?

Phil - That is incorrect! Yes, the answer is transistors because the most recent estimates for bacteria in the human body put the number of cells in there as about 30 trillion, but the world's biggest supercomputer Summit - it belongs to the US Department of Energy - and it's about 74 trillion transistors. And that's the size of two basketball courts. Let's move over to Team 2. That's you, Emma, and Chris Smith. So question number two, which are there more: of birds in the sky - I should say birds in the world, that's just a poetic way of saying it - or neurons in the average human brain.

Chris S - Hmm.

Emma - Wow, that's tough.

Chris S - 100 billion nerve cells in the average human brain.

Emma - I couldn't even begin to guess how many birds there are, but I would go for birds. But I'm not quite sure why.

Chris S - Are there more than a hundred billion birds on earth? It's quite high.

Emma - It is quite a lot...

Chris S - There's 7.7 billion humans.

Emma - True, but then birds can be much smaller, can't they?

Chris S - Yeah. So are we saying that birds are about 10 times more numerous than humans? That seems pretty plausible, actually.

Emma - Plausible, but I'm not sure if it's right.

Phil - Are you going to go with it?

Chris S - What should we go with then?

Emma - Oh, I don't know!

Chris S - Birds?

Emma - Yeah, let's do birds.

Chris S - Birds.

Phil - That is correct!

Chris S - Put it there! Look at that. We're off to a flying start.

Phil - Yes, fist bump. Excellent.

Chris S - My reputation's intact so far.

Phil - Good job. So the last estimate was actually two decades ago for number of birds; it put it between 200 and 400 billion. So big bounds, because birds are very hard to estimate. Likely it's gone down, but the human brain is about a hundred billion - on average, it's actually 86 billion. And the estimates for decline, the biggest estimate we've got is 30% since 1970.

Chris S - Brain cells or... is that the average human intellect?

Phil - Birds in the world! So we can be pretty sure that it hasn't gone down by enough to go below the number of neurons. So birds wins. Alright, as we enter Round 2: Team 2 you're on 1; Team 1, you're on nil; so it's everything to play for as we move back to Team 1. And this round is called Soft Spot. So Question 1: which animal, which lives in the bitter cold in the Andes mountains, has what's considered to be the softest fur in the world?

Chris R - Do you know any animals which live in the Andes?

Phil - Chris Smith, you seem pretty keen. Do you know the answer?

Chris S - I reckon I do, but it's not my go is it?

Phil - No, no no.

Chris S - Do I get a bonus point?

Phil - Not at all!

Nadia - Is it llama?

Chris R - Llama! Yeah, bring it on, llama!

Nadia - I'm not sure but...

Phil - Are you saying llama?

Chris R - I think llama's... I'll say llama. I'll take the fall this time though.

Nadia - Okay, yeah.

Phil - I'm afraid that's not right.

Chris S - Is it a chinchilla?

Phil - It is indeed a chinchilla. Well done other Chris! I'm sorry, Nadia, I gave you the wrong Chris for this round, so my apologies. But here it is. This is a chinchilla, here's a picture of one.

Chris S - They are really fluffy...

Phil - It's a tiny rodent, it's got... each follicle has at least 50 tiny little hairs sprouting from it. And it's actually so soft and fluffy it can't bathe in water because it won't dry quickly enough and it'll get bacteria and fungus, so it actually has to bathe in dust. So a very cool animal that. Right, Team 2: what mineral defines a number 2 on the Mohs Hardness Scale, the lowest defining mineral that you can actually scratch with your fingernail. And as a hint, it's widely used as a fertiliser.

Chris S - Well talc is right at the bottom of the scale and diamond's right at the top. So what's 2? And you're saying the mineral can be scratched - this Mohs Scale 2 can be scratched with a fingernail?

Phil - Yeah. Number 3, the mineral for that cannot. But number 2 is the highest one that can.

Chris S - And we use it as a fertiliser. So that's going to be something with phosphorus in it then.

Emma - I guess so but...

Chris S - Calcium phosphate?

Emma - I can't come up with a better guess.

Chris S - Sodium phosphate? Calcium?

Emma - Let's go with calcium.

Phil - You're saying calcium phosphate?

Chris S - Well that's bone though. That's quite hard.

Emma - Yeah.

Phil - I'm going to need an answer or a pass.

Chris S - Sodium phosphate.

Phil - Sodium phosphate? I'm afraid that's not correct! I'm sorry, the correct answer was actually very close in formula: it's calcium sulphate dihydrate, which is gypsum, if you've heard of that one.

Chris S - Yeah, gypsum. It's plaster of Paris isn't it?

Phil - And it's in chalk, and drywall, and all that stuff.

Chris S - That's sort of what I was going for. I got sidetracked. Where does the fertiliser bit come from then?

Phil - It is used as a fertiliser. In it's gypsum form.

Chris S - I might challenge that one, Emma, but...

Phil - Well it's still 1-0 as we go into the third round, and this is a particularly fiendish round, so if you weren't ready, now is the time. This round is called Weird Weather. Alright, so team number 1: what I'm going to do for both of you is describe the conditions required for a particular weather phenomenon, and I want you to tell me what that phenomenon is. Okay, so what weather phenomenon occurs the following conditions? First, a strong electric field in the atmosphere, usually from a thunderstorm or volcanic corruption; two, that field gets concentrated around a curved object like the tip of a ship's mast; and three, the air around this area ionises and turns to plasma. What weather phenomenon?

Chris R - It's got to be lightning, right? Does it need to be a specific sort of lightning?

Phil - I can't possibly comment.

Chris R - So there's famous... St Elmo's fire, which is a famous sort of lightning which is associated with ships' masts.

Nadia - I would go with Chris' answer because, yeah, it's something that's got to do with plasma, electricity, charge...

Phil - What do you think? Is that your answer?

Chris R - St Elmo's fire.

Phil - That is correct! Yes, I possibly shouldn't have given that with the physicist on this team. So you've got the right Chris this time! But yes, Saint Elmo's fire. What it is is a corona discharge around a pointed object, and it works on airplane nose cones as well. And back in the day it was considered a religious phenomenon, actually a good omen by many sailors. Team 2, here's question number 2, this is trying to get your lead back. What weather phenomenon occurs under the following conditions? Number one, dark thunderclouds; number two, either a heavy downpour or a rainstorm with nearly uniform size droplets; and three, the sun breaks through those dark clouds and projects against them.

Chris S - Oh, it's got to be a rainbow right?

Emma - But it seems too obvious. But it can only be.

Chris S - It's got to be a rainbow.

Phil - Is that your final answer?

Emma - Yeah, I think we say that.

Phil - I have to say that's half a point for that. So you can get your correct answer jingle I think. But the full correct answer would have been a triple or tertiary rainbow, which is quite a rare weather phenomenon so I haven't made it easy for you. But what that is is actually a rainbow that's projected onto the side of the sky where the sun already is, and so you need those dark clouds next to the sun otherwise you just can't see it, there's not enough contrast. But it does exist, there's several that have been sighted; it's very, very cool.

Chris S - So do we get half a mark for that?

Phil - So you get half a mark, and that puts you in the lead...

Chris S - And that gives us Big Brain of the Week award then, does it?

Phil - Team 2, you are Big Brains of the Week.

Chris S - Wahey! Do we get a round of applause?

Emma - Just about scraped a win there!

Phil - On half a point!

Chris S - That was lucky. Reputation intact.