091 = Optimal Darts and Smelling Sharks

Hello, and welcome to A Problem Squared, the problem-solving podcast, which is a lot like a window

in that

there is it functions in a framework of some sort.

We do.

And part of that framework is top-quality introductions.

Yep.

We are transparent.

That's true.

That's true.

And the

message is clear.

You can open one to solve a problem.

Yes.

You can open a window to solve a problem.

And you can also close it should you not want any noise, like you would our podcast.

That's true.

I'm Beck Hill.

I'm a comedian, a writer, and a pain.

See what I did there?

That's great.

Yep.

And that other voice is Matt Parker, who's a comedian, mathematician, and

silly.

Silly.

Oh, like a sill.

A windowsill.

Wow.

Got there in the end.

I was about to glaze over.

Nice.

On this episode.

I've checked the numbers on the optimal dartboard.

I look into sharks and blood.

And

we might find some any other business through the square window

You're a square window

Hello Matt.

Hello Bec.

How are you?

I'm good.

I'm good.

How have you been?

I'm good.

I'm good.

Thank you for asking.

So my big news.

I went to the election.

Well the election happened all around us, but I got to go.

In the UK, there's no like electronic voting or anything like that.

You get a physical bit of paper and you write your vote on it.

And I got to go to the room on the evening of the election where they count the pieces of paper to tally up the votes, which was a huge amount of fun.

Yes.

I was account agent.

That sounds pretty cool.

It's very cool.

Account agent sounds like if Dracula was in Men in Black.

Yes.

I mentioned to my friends that I was going as an account agent and they all got very excited about the costume I should wear.

Yeah.

And

several vampire-related outfits were suggested.

I was not swayed by those suggestions.

I did contemplate a sash.

You've done a YouTube video where you dress up as like a vampire.

I have.

And that was raised because I kept it just in case there's another video where I need to dress up as a vampire.

And I deemed this not that occasion.

I ruled out wearing a sash.

that says count agent as much fun as that would be in the end i i did put on a suit i wore a suit like a secret agent not like not like a not like a earpiece kind of agent just like a like a i was cosplaying as an accountant that's less fun i think you're getting too hung up on the word agent yeah because i'm good at costumes and if you'd listened to me you would have gotten way cooler reactions i and i don't want to startle anyone who's unfamiliar with my work was not there for a cool reaction

Now, to be fair, that said, I was in the convoy of some people in very good costumes because the reason I was able to get into the room where the votes were taking place is I was a count agent for a political party.

And the political party in question was the Count Binface Party.

Yes.

Friend of the show?

Your friend and mine, previous producer of this podcast, Count Binface.

Yeah, I hope Lauren doesn't start to get ideas and...

run for parliament.

We all know we're just

running out of time before

Lauren dons some kind of ridiculous costume and starts running for parliament.

Yeah, the Duchess of Dustbin or something.

It's inevitable.

And as they say, the important thing is just to enjoy the time you have and just know that it's fleeting.

That is what they say.

I say that to all children when it's their birthday.

Could say one day your producer will put a bin on their head and leave you.

Yeah.

No, so.

Count Binface is an intergalactic space warrior who runs in Earth elections because it's funny.

And

i mean there's a history of novelty candidates in in uk elections i

without throwing too much shade find them all to be all

all zaney no substance they'll just have a funny outfit and then that's it

and because we were at the election that the sitting prime minister was in so a lot of people will run against the sitting prime minister who traditionally is in the very safe seat.

They're going to get voted back in again.

But there's a lot of media attention and like their speech at the end of the results is always broadcast on TV.

So if people want to run as a novelty candidate, it's a very appealing constituency to go for wherever the sitting prime minister is.

So we were surrounded by other novelty parties and that no one had any substance behind them.

So I got to go along and I got to be there in the room as that was all happening.

Rishi dashed in at the last conceivable second to be officially present for the vote count, did his speech, and gone.

Binface, I'm very impressed.

Under the Bin, they're a politics nerd and a comedy writer.

So unlike the other novelty parties, they've got a lot of substance to back up their style.

He's really good.

Yeah.

And the media love interviewing Binface because they say almost slanderous but very funny things about the state of politics.

And so they're a great the media know they can go to to them for a very good soundbite.

And I got to watch people count things.

So I had a huge amount of fun drifting around people counting stuff.

It was a good time.

How about yourself?

I didn't do any counting.

What?

I went to the children's media conference in Sheffield.

The children's media conference?

Is that a bunch of children who secretly run the media?

Or is it a conference just for you?

Oh, man, I wish it was the former.

Wouldn't that be special?

It's just a bunch of people getting together talking about how no kids watch TV anymore these days.

I was about to say

they're all just sitting around going,

you got any ideas?

Yeah.

Anyone watching your show?

Nope.

Watching yours?

Nope.

My favorite panels were there was a panel where they discussed that very fact.

What's really interesting is a lot of parents will let their kids watch YouTube.

And you've kind of got the parent filter on, you know, like the child filter on there.

Like children's media in terms of television and stuff is very heavily regulated to keep kids safe.

So there's a lot of laws about

what you can and can't advertise, like the quality.

In the UK, there's got to be like a certain amount of education has to be provided, especially if it's a nationally funded thing like CBBs or CBBC.

You have to hit a particular quota of what is educational.

And obviously, fair representation.

I've done way less TV than you, but you know, particularly aimed at kids, but occasionally something I'll do will bump up against imitatable behavior

restrictions.

And that's a big one.

You can't.

Yeah.

Yeah.

In fact, one of the preschool shows I was writing on recently, there was a storyline pitch that was very cute where the character gets the sneezes for the whole episode and hilarious

things ensue.

You know, they sneeze, they're shot backwards, or they sneeze and a house falls down, or they sneeze and they shoot up into the air, or that kind of thing.

But obviously, the idea of that since COVID is

pretty looked down upon because it could suggest that it's encouraging kids not to cover their mouths when they sneeze or to try and sneeze as big and loud as possible.

So there you go.

Yeah.

So you've got to be super careful.

And the thing is like these things are in place so that parents don't have to be as heavily involved in the vetting process.

Like you know you can stick your kid in front of CBBC or CBBs and know that they're getting a relatively good good quality, relatively good level of education.

Nothing that's going to necessarily scar them for lives or anything.

But YouTube doesn't really have that.

Basically with YouTube, you say whether your content is kid-friendly or not.

It might run through a couple of algorithms to check for things and people can flag stuff, but it kind of relies on the people being the filters or moderators being the filters rather than there being a huge vetting process back and forth about what can and can't go on there.

But parents don't realize this.

Like, it's parents just think, well, it's here and it's here.

No one thinks about the fact that, like, children's TV, so much thought goes into it.

Like, so much thought.

Because children are sponges and they will soak up everything.

So you've got to be extra careful.

Not in a sense that you're sheltering them in any way.

I'm a very big believer in not patronizing kids.

I'm always citing Bluey as the perfect example of something that will

understand that kids are capable of taking in very important subjects, but we've got to be careful about how we go about talking about them.

And I just hadn't really realized that a lot of the public don't realize that.

And so they'll chuck their kids in front of YouTube and they'll watch six hours of fruit dancing.

which is very, very nice and calming and meditative.

But anything in large quantities, in large bingible quantities, is not healthy for anyone.

In the interest of, you know, the free market, if we hadn't removed all those restrictions and regulations, we wouldn't have had the creative output that is Skibba D toilet.

So there's something to be said for unshackling the creativity

of children's amusement.

Yeah, yeah, you're right.

And my other favorite panel is just called Put Your Money Where Your Mouth Is.

And it's where they get four people to pitch their

TV shows to a bunch of commissioners, and it was brilliant.

Well, nice.

Yeah.

And in what capacity were you at the children's media conference?

I was just a delegate baby.

Oh, just hanging out?

Yeah, just networking.

Lots of networking that goes along.

People who work in kids' media are like the nicest, loveliest people.

I did karaoke.

I think I mentioned it before, but I'm not drinking at the moment.

And I've been really enjoying that.

I thought I was going to be a bit nervous at karaoke because they didn't have any good zero non-alcoholic alternatives at the bar.

Either it was a free bar, so your choices were all the free booze or water, or like, I don't know, soft drink.

Yeah, and I didn't want to be full of sugar.

And so I was like, oh gosh, I'm going to have to do karaoke on just water.

Turns out, karaoke is just the level of natural high that I need.

Because once I got that first song under my belt, oh boy, I was there till the bitter end.

Amazing.

And that's how children's TV is made.

Our first problem comes from the rogue or the rog.

Let's go with rogue.

Not any rogue.

The rogue.

The rogue.

Do you think it's

Dwayne the Rog Johnson?

I do.

I've been sat staring at a dartboard for the last 40 minutes.

I understand that it's ordered the way it is to promote skill by having large numbers and small numbers near each other.

But is there a better way to place the numbers to achieve this?

So basically they just want to know about optimal layout and who figured it out in the 18th century and how.

I mean

they're close.

The current number system we think was the late 19th century, potentially early 20th century.

In my cursory research there's

no primary references for who did it.

The kind of accepted wisdom was it was a carpenter named Brian Gamlin in 1896.

But that is not settled fact,

but it has been, we can say unambiguously for over a century, it's been the current numbers on the dartboard.

And when this question came in, I was like, that is an interesting problem,

because I'm kind of, I'm aware that

the positions of the numbers on a dartboard is a very mathematical thing.

And I'm kind of conscious of that as just being something that is in the mathematical world, but I've also never looked at it very closely.

Yeah, so it was then kind of my, oh, I'm sure that's interesting.

I've just never dedicated any time to looking into it.

So, when the rogue got in touch and said, I've been living under a rog, I don't know why dance works,

I was like, Brilliant, I'll look into that.

And it reminded me because I just put out my video where Grant and I play pool against Jen and Raleigh.

And in the background of that video,

very astute viewers will spot someone out of focus playing darts.

That person is the good Beck Hill.

Yeah.

I think it was about three hours I spent playing darts.

You spend a very long time.

Perfect my throw.

We didn't rush the filming.

And you found a dart board in the corner of the pool hall and just got busy.

I did improve.

I did get better than what I had been before.

But I did then reach that point where my arm was just getting tired.

My arm was aching for days after that.

I remember you complaining for days after that.

Yeah, I did that anyway, though.

I mean, that's true.

But valid, this was a valid complaint.

Your arm was a bit sore after your arm.

Yeah.

Because then we finished filming and we were all like, oh, now we want to play some darts.

We've been watching you play all day.

We want to have a go.

And you're like, oh, more darts.

So we spent like another hour or two playing darts.

It was great.

I loved it.

I had a great time.

Good darts all around.

So I think that's it.

I think we've answered it.

I have wondered about this as well.

I've wondered who chose the order.

Because, you know, a QWERTY keyboard is, you know, there's been some thought that's gone into why the letters are where they are.

And it makes sense.

I just assumed that it was like throwing darts at a dartboard as to how they chose the number.

Oh, look at Hugo.

Oh, that cliché was a bullseye.

Turns out.

Potentially, it's way more thought through than they thought.

Sort of.

So no one's 100% sure what the original logic was.

That said,

now that people have come up with theories about what properties a dartboard should have in terms of the number arrangement,

the classic one that's been around for over a century is very good.

So even though it would have been worked out without the benefit of computers or modern mathematics or a lot of the techniques we're using now, it is a very good layout for a lot of the kind of properties we want to have in a dartboard.

So just, I mean, for people who don't play darts, to kind of give you a quick darts catch-up, you're throwing a pointy bit of metal at a circle across the room, and

the circle is divided up into slices as one would a pizza.

20 slices.

20 slices.

20 slices.

And each slice has a number.

So the numbers from 1 to 20 are arranged around the outside of the board, 1 per slice, as you would a terrible clock.

If you get your dart into a slice, you get that number of points.

Now, there's a few other things, like there are different regions within each slice where you might get double or even triple the value.

Yeah, like Scrabble.

Yeah, like Scrabble.

So you get double dart score or triple dart score.

There's also the bullseye and like a ring around the bullseye right in the middle, which are worth like, you know, 50 points.

It's actually more beneficial if you're going for points to go for the triple 20.

Yes, because that's 60.

It's It's a bigger number.

Which always throws me.

There is a scenario in which it's preferable to aim for the bullseye.

And that is if your aim is absolutely terrible.

Because

as your aim gets worse, the location you should aim for changes.

And if you're going to be lucky to get it into the board, aim for the middle of the board.

because it will just maximize your chance of getting something.

So there is a scenario in which the bullseye is good.

That said, if you've got any kind of control, even vaguely, of where the dart's going to go, then the bullseye is probably not for you.

Well, when you're playing darts, you're trying to count down from 300, aren't you?

So you start with, it varies either 301 or 501.

You start with a big number and one.

And then each time you score with the darts, you get to throw three at a time.

And then the other person has a go.

Each time you throw a dart, wherever it lands, you subtract that value off your score.

First person to zero wins with two caveats.

You cannot exceed zero.

If you score too many points that you can't subtract them all off your current running total, that shot just doesn't count.

Yeah, so if you had 50 left to get, that would be the one time where a bullseye would work.

The other rule is you need to finish on a double.

Oh, I didn't know that.

Your final shot has to land in one of the double value spots around the edge of the board.

Huh.

And that

is an interesting twist.

Like that one little game mechanic makes both darts in general and the arrangement of the numbers a slightly more interesting game because it adds a lot of complexity.

Because as you're counting down, you've got to make sure you can end, boom, double score.

And if you miss and you get another score, you've then got to work out a new way to end on a double.

You're doing maths while you're throwing stuff.

It's such a great game.

You're throwing pointy things while doing mental arithmetic.

What a game.

I can see why it's so enduring.

And why it's done in the UK, at least frequently in pubs where you have a drink.

Drinking famously helps both throwing pointy objects and doing mental arithmetic.

In the ROGs

problem is the assumption that you want to have numbers next to each other to be very different in value.

And that's because there's this notion that you want to make the game a challenge.

Because

the game would be effectively the same if it started like at one at the top and counted up two, three, four, five, all the round to twenty like a terrible clock.

And the downside to if they just went up in numerical order is you'd have one region of the the board with very, very low values, and you have another region of the board with all big values.

So, if you are aiming for, let's say, 19, and you think, well, I'm aiming for 19 because there's a chance I'm not super accurate, I might go one to the left or one to the right.

And by aiming at 19, if you're slightly off, you get 20 or you get 18.

You're still getting a very big score.

So, the idea behind the layout is to penalize inaccuracy.

So the idea is if you throw a dart and you miss the the slice you were aiming for, you're going to get a very different score to what you would have got if you'd hit the one you wanted.

Whatever you're trying to achieve, being inaccurate has to mean you no longer achieve that to make it an interesting game.

Yeah, like in a video game like in Mario or Sonic, you have the platforms between spikes.

You're not going to put all the platforms together and then just a whole bunch of spikes.

Uh i i it's the inverse of darts because in darts you throw the spikes at the game as opposed to throwing the game onto the spikes.

If you take that idea and you run with it, the idea is you want to penalize inaccuracy.

So the whole point of the game is to be accurate at throwing the pointy thing.

There's some things you do or you don't want.

So one of the common criticisms of the current layer, like it's very, very good, but it's got a few hotspots, let's say,

where not all the regions of the board have the same kind of average value.

So, what you can do is if you're a little inaccurate, you can pick a hotspot and aim for it.

So, I mean, if you're dead accurate, you aim for

triple 20 because that's your maximum points, like you're saying.

But 20 is flanked by 1 and 5.

So, if you miss by a bit, you're getting barely any points.

So, if you're not sure if you're going to exactly hit it, or you might be off by a bit,

then it's actually preferable to aim for 7

because 7

has 19 on one side and 16 on the other.

So, ironically,

if you were accurate, you're only going to get 7 each time.

If you're a bit all over the place, the average value from those three is 14.

And so, that's like the high that's the highest average of three consecutive slices on the board.

And that whole region on the board, if you're randomly hitting between 7, 19, and 16, you'll average 14 points per dart.

And that kind of region of the board, the region that runs from, it goes 8, 16, 7, 19, that's your hotspot on the board.

If anyone's listening who's not that great at darts and in a pub you're told, hey, why aren't you joining a game of darts?

The secret is ignore 20.

If you aim for 19,

that's your best kind of higher than average region of the board.

And the region around 19 is where there's the best concentration of big value slices that you might hit.

So now we've got two things we would like from an optimal dartboard.

And one is that you want to have a big difference between two consecutive slices.

So you're penalizing missing.

Secondly, you don't want to have a hotspot.

You don't want to have a region which has an above average value.

Interestingly, those two requirements are in contrast with each other.

Because if you're having really big variations somewhere on the board, you've got to have another region where a bunch of similar-valued ones are kind of clumped together.

So there's a push and a pull between these two criteria.

What you need to do is find some way to measure those two things, and then you've got to try and find an arrangement which gives you a balance of the two.

So, what you actually end up doing is you try to find an arrangement of the numbers such that

it's got the smallest maximum difference between any two consecutive slices.

Okay.

And by measuring that,

you end up with a nice balance, but also big enough differences.

What you can do, though, to really force the need for differences is as well as looking for the difference between two consecutive slices, you also look at and try to minimize or maximize the square of the same thing.

And by squaring it, you're adding more emphasis on bigger differences.

Because squaring just big numbers get bigger, small numbers don't get as bigger.

So by also squaring the same thing and checking that separately, you're then providing extra emphasis on the importance of big differences.

So those are actually

the four criteria.

You want to find the biggest average difference between two slices.

You want to find the biggest average squared difference between two slices, consecutive ones.

And then you also want to minimize

the maximum value of that for any given board, and you want to minimize the maximum version of the squared value of that.

So, mathematically, that's how you lay it all out.

I'll be honest.

You have lost me.

I've missed the board.

Yeah.

So, I mean, what's interesting about this is this is some

fairly advanced mathematics, not like ridiculously abstract mathematics, but it's not just standard maths you will have learnt at school.

This is niche/slash unusual mathematics.

So the original layout was absolutely not done this way.

There's no way the original designer sat down and went, oh, I need to make sure this measure on the cyclic arrangement has this property.

They just would have been eyeballing it and going, oh, here's a way that I can do it such that the differences are pretty good and there's no overly significant hotspots.

Is it a bit like

in baseball, there are many different ways in which you can check different stats?

Like, there's many different stats that you can work with to work out different ways of playing the game and

moneyball.

Let's just say money ball because that is my shorthand.

However, baseball wasn't invented with those things in mind.

Yeah,

it's yes, I will say it's a bit like back in the day, baseball scouts would just be like,

I like the gumption on this kid.

I've got a feeling they're going to be good at playing the baseball.

Whereas now we're like, oh, we can calculate all the different factors and determine who is the optimum person at playing baseball.

And when the dart ball was designed, it was before we had that kind of process.

So it was just someone going, This feels right.

This is probably a good one.

And it turns out they were right.

It is.

It's very good.

Whereas now, we can exactly quantify precisely how good or bad it is and which is the best.

Got it.

Okay.

Now there's a new criteria in town.

Recently, people have started saying, oh, on top of everything else we want a dartboard to do in terms of the number arrangement, we also want it to alternate odd, even, odd, even all the way around the board.

Huh.

Do you want to have a guess guess why

we would want to alternate odds and evens

around the board?

Is it

because it's not immediately obvious?

Has it got anything to do with the whole having to end on a double?

You are spot on.

Yes.

It's to thwart people ending on a double.

And quite pleasingly, when I was reading a bunch of research about dartboard arrangements, I saw that was cited to Easterway and Haig.

I then realized I know Easterway.

That's my friend Rob Easterway.

Oh, he wrote a book called The Hidden Maths of Sport.

You've met Rob.

I was going to say, I know that name.

That's my mate, Rob.

And in all the literature I was reading, it didn't say why we want this odds-even thing.

So I just messaged Rob, and Rob very kindly recorded a quick message for why

they came up with the idea to alternate odds and evens.

Hi, Matt.

When John Hague and I were examining the number patterns on dart boards, it occurred to us that one way to penalise players who don't throw accurately is to make the numbers around the board alternate between odd and even.

And the reason for this is that you have to finish a darts game with a double.

So if your target is currently 24, then to finish the game, you've got to get double 12.

And at the moment, on the current boards, if you aim for the 12, its neighbours are 5 and 9, which are both odd numbers.

And that's bad news because your target score, if you happen to miss the double 12 and get a 5 or a 9, your target is now an odd number.

So you can only finish on a double if you spend another dart reducing that back to an even number.

Throw it a 1, so you now got an even target and go for that again.

And a weakness of the current dart board is that the 16 is next to the 8.

So if you miss double 16, you might land on 8, and that's still an even target, so you've still got an out.

So they could improve the difficulty of the current board by making it odd-even.

Huh, that's really interesting.

Yeah, so you were absolutely correct.

And so Rob had this idea, put it in his book, and now that's been folded into the literature.

It feels like when it was designed 100 years ago, they had an awareness of that because while there are a bunch of evens that are next to each other, it does largely go alternating odds and evens, just not completely.

And we now know that it's impossible to do everything at once.

You cannot alternate odds and evens while getting an optimal arrangement of the numbers in terms of how big they are.

So, the actual maths was done by Dave Percy at the University of Salford up in Manchester, and they did a lot of research into the optimal arrangement of a dartboard.

And in 2011, they found the best arrangement.

They published it the next year and I really struggled to find any of their the 2012 paper.

I couldn't find it easily online but quite conveniently they announced their discovery of the optimal dartboard at the Mass Jam conference that I help organize.

So I was there in the room back in 2011 when Dave Percy was like, hey, check it out.

This is the best arrangement.

Because knowing what you want and actually finding it is difficult.

It takes a computer to do.

They wrote some probably very good code to then search and find it.

And that is now, that is the best arrangement.

That's it.

So the Percy board is the best possible arrangement.

I will link in the show notes to a paper written in 2022.

by a researcher in Turkey who does a fantastic summary of the history of the mathematics of dartboards.

They show that the Percy one is optimal while looking at some other ones and the way you can balance and all these things I've been talking about, how you can measure

the nature of the distribution of the numbers.

They break it all down in terms of the maths going on behind the scenes.

And they do find two other alternate arrangements.

I'll put a picture of the classic arrangement of the dartboard and the Percy arrangement and maybe even these two other alternate ones if people want to have a look at those so you can see what the options are.

But at the end of the day, if you want to have the alternating odds and evens and you want to have the optimal distribution and you are trying to balance them out, the Percy one is the best arrangement.

So I will make sure we have a link to Percy's design.

And it's very similar.

Like eight of the 20 numbers are in the same place as they are on the standard board.

So it's not dramatically different.

It's just kind of shuffling a bunch of them around a little bit

to just kind of tweak and improve.

So it's technically a little bit better, but not dramatically better than the classic one.

Can you buy the boards or can people just cover up the numbers and tape and renumber them?

They did do a limited run of them in like 2012 or 2013.

I don't know if they're still available.

You might have to get out, you know, some pliers

and move and rearrange the numbers on your board, but I will will give you the guide.

So you can, you're right.

Tape over the board you've got and sharpie on these improved numbers.

I have one more question to ask, Matt.

We're talking about the arrangement of dartboards, and this is the problem that the ROG sent us.

So, first of all, ding.

To me,

as far as I'm concerned,

that's a ding.

I think you've

fully answered that.

Is there a better way to place the numbers?

Yes.

Yes, there is.

Is there a tactic that people should play by if they're playing with a standard board?

It depends how good you are.

So

my friend Zoe Griffith did a thing a while ago, which was looking at if you gradually increase the level of uncertainty in your throw, where the best spot to aim for moves to.

So it depends how accurate you are.

I will also say that there are still some assumptions around the best arrangement because it assumes that aiming for any one slice is equally easy, but some are sideways and some are vertical.

And actually,

it's easier to aim.

Side to side is easier to aim if you're not good at darts, whereas

metering your power to aim up and down is harder.

And the height of the player, too.

And the height of the player.

So we're assuming all slices are equally easy to aim for, and that's not true.

And as we discovered with

Rob's contribution, we might come up with new measures for what we want from a dartboard.

So, maybe my idea of the equality board, where it helps bad players but penalizes good players, we could decide actually that's our new most important criteria, and would have to recalculate and look at new arrangements that achieve that.

So, it's the optimal arrangement based on what we want from a dartboard at the moment, but there are still some things we're not factoring in, such as the orientation of the board.

Yeah, well, you can get a lot of those

interactive ones now where they sort of project stuff on there.

So you can play games where they do change the layout of it depending on what sort of game you want to play.

Yeah.

I think the board should be able to spin.

Aha!

Yeah,

somewhere between Wheel of Fortune and Dart.

Matt, can we invent that?

I think we just did.

Our next problem comes in from the Chris.

I mean, they just wrote Chris, but I assume they'd like to be known as The Chris.

How they're following the rogue.

Yeah.

The Chris says sharks can apparently smell blood from quite a way away.

They're not sure what that means, as they can presumably only sense something that is in the water that is around them.

Good point, the Chris.

Their main problem, though, is if they cut themselves, how long would it be before a shark got a whiff of them and could home in?

How long have they got to get out of the water?

Or stated alternatively, how quickly does blood spread in the sea?

Okay, the Beck.

Have you got a solution for the Chris?

I do, the Matt.

I'd heard several sort of things about sharks can smell blood from a mile away or they can smell it a quarter of a mile away.

And my first thing was, like, how do they know

that led me down a series of rabbit holes well I suppose I'm gonna go from the problem backwards so how quickly does blood spread in the sea blood in the sea very similar to a fart in the air it's all to do with diffusion so if things were sort of sitting relatively still but sort of diffusing then obviously the further away it is the fewer particles there are and if you and I were in a room with completely still air and one of us farted,

but there was no movement in the air, it would take quite some time for some of those very dispersed particles to make their way to my olfactory system for me to then recognize it.

And therefore, deduce that you had deltaized it.

Well, if you recognize it, you deltized it.

I think that's the expression.

Yeah, that's what they say.

Yeah, that's the same.

But obviously, air and

water move

So at first I thought okay like waves waves actually only really affect towards the surface of the sea.

You know how you see people in like a wave machine pool and they just kind of go whoa and they bob up and then come back down.

They don't necessarily get pushed along by the wave.

You know, you only tend to get pushed along by a wave if you're at the right point.

point of the wave breaking and you can manage to catch it.

Otherwise, it just kind of like passes by you.

You sort of raise and then fall again.

On a traditional ocean wave you would do like a little circle loop as the wave goes past you.

So it's not exactly up and down motion.

There is side to side but it all brings you back to where you started.

You will not go anywhere on a non-breaking ocean wave.

What does move water currents?

And that usually comes down to temperature, water temperatures, in the same way you get with air.

So when the temperatures are different in different parts of the water, warmer water will move towards.

And also if you're near where like rivers and stuff are coming out as well, that will start to affect the movement of the water in those situations.

Also stuff coming up from under the ground.

And then just animals, animals, schools of fish swimming through will interrupt the water currents and stuff as they're swimming through.

I then realized that, yeah, how quickly blood spreads in the sea, it really boils down to where you are in the sea, where's the water going, how much blood is there, etc., etc.

And then I tried to find like how they actually tested, like, how did they come to the conclusion of exactly how far away a shark is?

Oh, yeah.

Like, how do they know it's a mile or a quarter of a mile or whatever?

Well, given that

they say both a quarter of a mile and a mile, it means we probably don't know exactly, but we do know one thing for sure, and that's that sharks use the imperial measurement system yeah yeah yeah exactly but I'm imagining you would put so let's say if we let's say just for ease of sake you you're working in metric you'd put a whole bunch of sharks in a long row 10 meters apart

and then you put blood at one end and you see where the point is where what's the most distant shark

that comes to the blood.

It is a very shark intensive way of doing the research, but I feel like it would be the most accurate.

Yes.

I was hoping there would be something like that out there.

Nope.

I couldn't find anything.

All I could find was either things that were pushing the idea that it's a mile, and then a lot of zoologists or marine biologists dispelling this and saying, no, it's not true.

It's another problem on a problem squared where the messiness of biology and no one agrees and there's always an exception.

Yeah.

Now they do have a very good sense of smell.

So, according to Louis Villazon, who's a zoologist, they say sharks actually have roughly the same sensitivity as other fish and can detect smells at between one part per 25 million and one part per 10 billion, depending on the chemical and the species of shark.

At the top end, that's about one drop of blood in a small swimming pool.

So, that's pretty impressive.

Okay.

But not

hugely unbelievable.

It's not a mile.

And it's also when you think about like how a dog can pick up a pretty decent scent.

My hamster can tell if food has entered a room.

Oh, wow.

He's little.

He's only got a little nose.

But then again, most of us can.

You know, you can usually tell.

Oh, someone in the neighborhood is making bacon.

Yeah.

There's a barbecue nearby.

Yeah.

So like it's, that's actually not, you know, it is impressive, but.

It's also, it's not like if you put a drop of blood in a swimming pool, a shark will go nuts.

I think that's what a lot of people seem to imagine.

So if we're looking at the maximum speed when they're attacking in water, sharks can travel at 19 kilometers per hour.

That's pretty swift.

So if you had a cut and currents were able to carry that a kilometer

away.

You got three minutes to...

get out of there.

If you want like a math C type answer, that's what it is.

And I do.

And now I'm I'm happy.

But twist.

No.

I know.

Sharks don't really care about human blood.

Sharks don't like humans.

We're not tasty to them.

They don't really care.

So it's not like smelling a barbecue.

It's like smelling a salad bar.

Yeah, exactly.

They're a bit like,

sharks generally don't like people to eat.

We have a lot of bones.

We're sort of more bone than we are flesh.

We're no seal.

No, exactly.

And like, and the type of bones that we have aren't great.

Apparently, our flesh isn't delicious.

We're not like big, chewy, fatty seals with all that.

I'm okay with that.

Yeah, so sharks generally don't like eating people.

Sharks tend to attack because either they're territorial or they think a person is a seal because they tend to come up from under them.

And a seal can sometimes look like a human, vice versa, if you're swimming on top of the ocean.

So most of the time when sharks attack it's not because they're like tasty humans they're like oh a delicious lunch oh no this isn't what i wanted your blood's not gonna attract them in any capacity or at least according to dr lauren simonitis overall you don't really need to worry about whether you're bleeding or not so to go back to the question If you cut yourself, how long would it be before a shark got whiff and could hone in?

How much do you look like a seal?

That's the answer.

Unless someone is throwing chum for things that sharks like to eat, like other fish or other marine animals, unless you're having a little swim through all that stuff,

you're relatively safe.

So I'm not saying please go and actively swim amongst sharks unprotected, but I am saying

the whole danger of them is severely overblown.

What was interesting was when I was trying to find out how they tested this fact, which now we know isn't a fact,

was

they did do some tests to see how sharks smell helped with their navigating.

And they found that a shark will know the source of blood.

So if it could smell the blood of prey

that had come along on a current, it can tell which nostril it hit first

and can turn towards that smell, and then

using the nostril on each side, steer themselves.

They're actually really good at navigating via smell.

So I thought that was really fascinating.

You were reassuring for a while there.

Now you're back to terrifying.

Well, if you are scared, cuttlefish ink is a reasonable shark repellent.

Like cuttlefish have a natural shark repellent in their ink.

Sharks are not a fan.

There's been studies and tests to see whether they can start using or manufacturing a sort of synthetic version of cuttlefish ink to help just ward sharks away from heavily populated areas so that they're not crossing over into each other's territories and causing issues.

That's great.

Gio, I think you can smell coming a mile away.

I think I can feel it in my right nostril.

Hang on.

Yep, now it's hit my left.

Yeah, yeah, yeah.

There's a ding in the water.

We're going to need a bigger pod.

Yeah,

a bigger pod.

That was the correct answer.

Well done.

Ding, ding.

There's some gag in there about whales and pods, but you know.

Oh, yeah.

We leave it to the listener to assemble that joke themselves.

Yeah.

Ding.

Ding, ding, ding.

Well done.

Thank you.

It's time for any other blindsness.

Oh, good work.

Thanks.

I was trying really hard to think of other window words.

Several of you, and we appreciate every single one of you, wrote in in response.

Well, okay, a very large group of people wrote in response to our do dogs have four legs or two arms and two legs.

A decent percentage of those people were telling us the same facts.

And it is interesting facts.

I appreciate everyone who said this because we were talking about what would then be worn on those legs slash arms.

And someone pointed out in the German language, the word for gloves, which we were using as part of our argument, translates to hand shoes, shoes for your hands.

So

implying that hands are just feet where you'd normally put your shoes.

I don't know.

I don't 100% buy the argument that this lends any

additional weight to the

arms or legs argument, but I do accept it as a very interesting and fun fact, and we always enjoy a fun quirk of the German language around here.

I would argue that maybe arms are a type of leg because you've been known to wear socks on your hands when you're riding a bike.

As gloves.

I was improvising gloves.

Were they gloves or were they just hand shoes?

They were definitely hand socks.

We also heard from Michael.

who said, hi Becca Matt.

Just listened to episode 88 and had to ride in solidarity with Beck.

Plain salted chips are without doubt the superior flavor, be it pringles, regular chips, kettle-fried, whatever.

No.

I have some friends whom I love dearly, and whenever we go over, their five-year-old always says, Uncle Monkel.

I'm guessing that's Michael.

We got your favorite, salt and vinegar.

And don't get me wrong, I like salt and vinegar, but it's not the best flavor.

That's wisdom from the mouth of children right there.

I think they're just gently trying to correct Michael's, you know, accidentally thinking that plain salt are the best.

They're doing their best to correct him.

I would say that this sort of nonsense coming from the mouth of babes is why we need to regulate children's media better.

Oh, wow.

Wow.

Callback.

Don't be so salty.

Ah, nice.

Thank you so much for listening, especially those of you who are right about the best flavor of crisps slash chips.

We would like to thank, in particular, our Patreon supporters who support us financially and allow this show to continue.

We love all of you, every single one of our listeners,

but it is nice to be able to financially justify the amount of time and effort that goes into this show.

So, without any further ado, we will thank three of our Patreon supporters at random by mispronouncing their names.

And on this episode, those three supporters are JU Stimb

I

Richler,

Steph Han

Wilm

Eroff.

B.

Nook

Asner.

Thank you so much for supporting us.

Thank you very much to everyone, though, for listening and for telling everyone to listen to this podcast.

Word of mouth is also the best way to support us if you'd like to.

And

thank you to my lovely co-host, Matt Parker.

Oh, thanks.

To myself, Beck Hill, the other host, and to our fantastic glassy gal.

Would you describe her as the void in our double glazing?

Yep.

Let's go with that.

Acroja, Lauren Armstrong, Carter.

Lauren Armstrong Glata.

No, I've got nothing.

I'm so sorry.

I'm so sorry, Lauren.

Oh boy, really regretting opening this episode by saying I was a writer.

She's going to quit and go into politics.

That's a wrap, folks.