An Honest Dad Ranking (Out Of All 2 Billion)

0:28Welcome to The Rest is Science. I'm Hannah Fry. Island in the Bay of Plenty region. It's geothermally very active here. Hold on. I want to get the joke. How do you spell it? R-O-T-O-R-U-A. Rotten Rua. My aunt-in-law calls it Rotten Rua because it smells rotten. It is a very geothermally active area. It's like Yellowstone in America. As soon as you drive in, you smell all this sulfur. Let me make this very brief. We drove into here from Auckland. So where did we stop along the way? You guessed it, Hobbiton. And it was beautiful. There was a rainbow in the sky as we stood outside of Bilbo's door.

1:10It was incredible. So exciting. My daughter fell asleep as we finished the drive to Rotorua and the smell came into the car as we approached and she wakes up and goes, who farted? and I said no no one farted the earth farted the earth farted and by the way this is where we're going to stay for another nine days so enjoy yeah thank goodness you'll adapt to it quickly you adapt to it very quickly like it took about half an hour before we were like wait did we leave no but I mean and it doesn't cling to your clothes apparently

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4:05Anyway, speaking of my daughter, the object I want to show you today is the mug that I'm drinking out of. Did you see my short about this mug? I did and I loved it. Tell us the story though. I'll tell you the story and then I'm going to reveal a bit of the story I did not tell on YouTube. Okay, this is the uncensored full story. For people who are listening rather than just watching, at the moment Michael is holding a mug. It looks like it could hold a decent cup of coffee. I'll tell you that. And it says, number 1 ,093 ,750 ,012, dad. Not number one dad. It's an honest ranking of myself. Now, I would have ranked myself higher.

4:48I would have chosen like, I don't know, maybe top half a million. How many dads are there? Very good question. I had to look this up. Apparently, there's an estimated 1.5 to 2 billion dads alive on Earth right now. So you're not even top 50%. I'm not even in the top half. So I've always thought number one dad on coffee mugs or barbecue tools is kind of, it's kind of braggy. Okay. Like I am not, I'm not the number one dad. I'll admit that, you know, I, I, I aspire to number one. I look forward to growing. I think growing, not just as a dad, but as a person is a great thing a parent gets to do. look i want something also that it would just be funny if the mug ranked me for real or it tried to now i would have put myself in like the top half million or so that's pretty braggy is that still braggy so i looked it up and by looked it up i mean i just google searched it and i looked at like a few links and they all kind of said uh there might be one and a half maybe two billion dads total alive right now on earth.

5:56So that's your kind of bounds here between one and two billion. Where do I fall? Top million is like half of a thousandth of a percent. I know that would be really high when you think about it. So I'm kind of happy that that didn't happen. What happened is I said, well, I got to ask my daughter now she's six years old. And so what I did is I drew a line on a piece of paper and I, cause she, she, she understands, you know, on a scale of one to 10, where would you rank something? So I said here, this is basically what that is on a scale of the worst dad in the world to the best dad in the world.

6:36Where would you put me? And she put me in the bottom half and I didn't know what to do. I'm like, well, this is what she said. Now this has got to be how I rank myself on the mug. because it's what my daughter said. I can't ignore that, but I do wish I was higher. Now, what I then did is I measured where her mark on the line was, and I took that ratio, and I compared it to the 2 billion dads who are alive today, and that's how I arrived at 1 ,093 ,750, but then I added 12 to make it look less like a round number, like I had more precision. This was exactly where my next question was going to be.

7:19Because if you're 1 billion, you're measuring to nine significant figures. What kind of laser electron microscope were you using to work out where she put her mark on this line? But now you've clarified it. Still though, you're still measuring to six significant figures, were you? Well, yeah. So I'm trying to remember exactly how I did this. I mean, 750, this is just a quarter. So did I really just, was I really that specific? I must have been. Because after I did the math, I had 750 ,000 and a bunch of zeros. But no, I wasn't counting how many atoms were on either side of her mark. Now, I love this.

8:02So she and my wife then turned it into a custom mug. And I think it gives me something to aspire to, to be better. My daughter, I asked her, do you really think I'm in the bottom half? And she's not really happy with the amount of screen time she gets. She's not happy with the amount of candy she's allowed to have. I'm not sure if she would be the best person to assess how good a dad you are, though, you know, for those exact reasons. I think that her opinion is biased. And actually, I don't think she should take her word for it. I think what you should do is you should go around to all the people who would be capable of making this assessment.

8:41So your wife, her school teachers, maybe a pediatrician, you know, all kinds of different experts. And then I think you should weight their responses accordingly. Get a fair, proper metric. I know. Rather than just asking a six-year-old who really doesn't, I think, know yet all the different ways a dad can be, I should have impaneled a jury that would actually rank me in their experience. Maybe I'll do that next year. But I think in some ways I also kind of think it's fair. Like I don't think I'm a bad dad. I don't think that I've had a lot of challenges. I'm lucky enough that I haven't had to make a lot of the same sacrifices that other dads have.

9:28So I'm happy for them to be ranked above me. Like what makes you the number one dad? It can't just be that you're fun and like you've never had any kind of struggles. Like there are dads who've had a hard time and they've done much more heroic things and harder things. They've made sacrifices that I haven't. Like I just. So again, that's why I don't want to be called the number one dad. My fundamental problem with this is that you're essentially ranking dads on one scale, you're literally creating a ranking of them. You've got to weigh up all of these things simultaneously. I think that what we should do is we should have a multi-dimensional dad ranking system.

10:13Then I think that you can say, I'm the 1 ,93 ,750 ,012th dad according to this particular metric in this particular dimension. I mean, look, let's take a proper data science approach for this. Let's take all of the different variables. Let's do a principal component analysis. And then we'll find out who the real best dad is based on everything. And then we could do it to moms, which this brings me to the secret part that I have not revealed yet. So we'll show on the screen the actual picture that my daughter drew ranking me on this line. Okay. So as you can see, it's in the bottom half. It's just, it's just a pencil line.

10:56And she made a little tick mark down a little bit low in my opinion. That's what I showed in my video, but I'm going to send you, I'm going to, I'm going to message you, Hannah, the full image. I removed some of what was on that page just to avoid the distraction because a short can only be so long. Okay. So I have just sent Hannah the unredacted, uncensored ranking. Is one of these for your wife? It is. Oh, lordy. Okay. Yeah. Because of course, after I had my daughter rank me, my wife couldn't help but be like, okay, but what about me? So she drew a line and said, worst mom, the best mom, where would you put me?

11:37And here's the results, listeners and viewers. Okay. The only thing I can't tell is which one is which, but should I give you my guess? Because one of them has all the hallmarks of being written with a mechanical pencil. Ah, okay. Yes. And for those of you who are just listening, I'll just, I'll explain that we're just looking at the back of, I think it's a, an envelope and like a ripped up envelope and it's got two horizontal lines with tick marks on them. One of them has a tick mark that's even closer to zero than the other. Yeah. One of you, one of you did worse out of this than the other. Okay.

12:10I'm going to guess that your wife did worse. She did. Yeah, she did. Oh, that was brutal. I mean, it's barely in the first, it's barely in the bottom quarter, you know? She barely makes it 25 % of the way along the line. Well, to be fair, I think my wife had suggested brushing my daughter's hair that morning. So that knocked her down a lot. Absolutely fair. Yeah, no, I felt terrible when my daughter ranked my wife below me. I'm like, oh, no, this Father's Day gift is turning into the saddest, most competitive thing I never wanted it to be. But it's an important piece of family history now, this ranking.

12:51How many mothers are there? Are there a similar number of mothers or are there more mothers than fathers? That is such a good question. And I did not come prepared with an answer. Well, I mean, let's just do a search. I'll do the exact same, completely unrigorous search. All right, so soundvision.com, statistics about mothers around the world. They say there are 2 billion mothers in the world. And 2 billion is about the same number I get when I look up how many fathers are there. There's a Reddit thread from They Did the Math. And they put it at, whoa, this person calculated 1.06 billion moms.

13:28That's half as many as that other figure. So I was going to say, actually, if I would guess, I would guess it would be lower, right? Because there is a physical upper limit on the number of children that one woman can have. And so you get people like Elon Musk, right? Who's got like unknown number of children or Boris Johnson, unknown number of children with many different mums. So I would guess that the number of mums, whereas I don't think you very often get it the other way around where someone has like 15 children, you know, where one woman has like 15 children. Right. So the things we're considering are if a mother has multiple children with multiple men, then those kids all have just one mom.

14:20But there are a lot of dads that have been created in that scenario. Agree. Agree. The reverse is also true. However, there's less of an upper limit. Right. Right. You see what I mean? And so I reckon the average number of kids per dad is higher, slightly, possibly, which means that the average number of dads or the number of dads should be lower. It's my guess, you guys. You're saying the number of dads should be lower. Yeah. So the mom category is more competitive. There's more in it. I'm basing this on no evidence whatsoever, right? Just having a story about Boris Johnson and Elon Musk in my mind.

15:03Well, I mean, this is a part of like critical thinking, you know, let's figure out like, how do we approach this not having already consulted the experts? And yeah, so I don't know, my wife, her number might even be like, what if her number was the same? Because even though she was lower, it was out of more moms? Wait, would that work? Yes. Yes, it would. Yeah. No, wait, you'd be the other way around. Sorry, it'd be the other way around. She would need to be higher to have the same rank. Yeah. Right. Uh-oh. The thing that this reminds me of is there has been really extensive research into the number of sexual partners that men and women have in heterosexual relationships.

15:43So it's a bit of a heteronormative story. But what's really interesting is that when it comes back, the average number of partners that men have is higher than the average number of partners of females, okay? Which sort of doesn't make sense because in the same way as when you have children, you kind of have to have a matching, right? So there were early suggestions, which I think were basically founded in sexism, which said, okay, well, the reason why this still works is because most women have a smaller number of sexual partners than most men, but there are some women who have an extremely large number.

16:20And if they're not included in the sample, then that's used the average and that's what's going on. Anyway, turns out that's almost, well, it's almost certainly not the case. Certainly not the reason why you see these differences in numbers. The first reason, actually, that you can get this real clue when you look at what the numbers actually are, if you look at a distribution of the numbers of sexual partners. And women's has this like very neat distribution, sort of as you would expect you know you've got like sort of nice tails on either side of the distribution or on one side anyway because it's sort of cut off at zero isn't it it can't have negative well you can have negative encounters certainly but not negative

17:03but when you look at men's right you don't see that same pattern instead you see these really big peaks at numbers that are divisible by five. So essentially, and there's two reasons for this. Two reasons for this. One is that women are more likely to say, this is like evidence of back to the South of Africa. This is not just sort of hearsay, although I am doing this from the top of my head. So please correct me in the comments if I've misremembered this. But women are more likely to say, okay, there was this person and then this person and then count upwards, but like thinking of each individual person.

17:40Yeah. Whereas guys are more likely to estimate and be like, wow, five a year for 10, you know what I mean? For this many years equals this. Yeah. Oh, fascinating. And also women are, because of sort of cultural expectations, more likely to estimate downwards, whereas men are more likely to estimate upwards. Right. But anyway, I just, when you have, I find those kind of problems very, it's like weirdly mathematically interesting where it's like, you know, there must be a pairing. as be a mom and a dad. And yet the statistics for each group individually are not the same. So you get into paradox territory very easily there.

18:18I really like it. I like it too. I've got the most important question though about your mug. Does it taste good when you put coffee inside it? Because I think some mugs, coffee tastes better in some mugs than others. I'll tell you, Coke Zero tastes delicious out of this mug. That's what's in here. I used to drink coffee all the time. I drank so much because my dad did. He would brew up a whole pot of coffee just before bed. He thought it was really cool that he could drink coffee in bed and then still go to sleep. I got really into it. Today, I'm just too, I run too hot. Literally temperature-wise, a hot beverage just makes me too hot.

18:56So I drink cold, cold caffeine. But does it taste good? It tastes good. And there's something about the physicality of a mug. that's just like so sophisticated. It makes me think. It makes me savor. I can just do a little like, you know, I'll do a little slurp, a little ASMR here. Go on. Oh, that sounds like coffee, but it's not. Well, I think you should get your daughter to update her line every year. And I suspect that as she gets older and sees that you put that number on a mug in honor of her drawing, I strongly suspect that your number will increase. I would hope so. I hope I earn it though.

19:38But I will say that of all the shorts I've made, she loves the one about this mug the most because it's telling a story about us, you know? And so, yeah, maybe she'll take it a little bit more seriously next year. I'd love to crack into the top billion at least. Like, goodness. It is funny though that being the number 1 billion, 93 million and so on dad means that from an angle, it almost looks like I have a number one dad mug. And then I can be like, psych, I didn't win the competition. I actually barely placed. Okay, should we go for a break? And when we come back, we'll be answering some of your questions.

20:23Tomorrow morning is knocking. Stock your fridge now. How about a creamy mocha frappuccino drink or a sweet vanilla? Smooth caramel, maybe. Or white chocolate mocha. Whichever you choose, delicious coffee awaits. Find Starbucks Frappuccino drinks wherever you buy your groceries.

20:46Okay, we are back. And first up, we've got a question to Hannah from Catherine and Eli. Here's the question. Hello, I'm writing on behalf of my son, Eli, who is 11 years old. He's a budding scientist and sailor in Sydney, Australia. He loves your show. He never misses an episode. Eli's question, what would be the most efficient way to use a fan to power the sail on a sailing boat? Eli's idea, put a huge industrial fan on a second boat, which would motor next to the target boat. Thank you in advance, Catherine. I absolutely love this. I love this question. This is my favourite bit of the week, by the way, when we get to answer Elizabeth's questions, especially when they're like little ingenious ones like this.

21:32Because the thing is that the intuitive logic is there, right? A sail can't distinguish between wind that's created by the geophysics of the Earth and wind that's created by a fan. So if you stick a fan on a boat, it should make sense that it would move. Eli's not the first person to have had this idea. And the kind of traditional formulation of this is that you just put the fan on the same boat. So you have it on the same deck, just point it at the sail. And when people had like worked this through, they had come to the conclusion that it wouldn't work at all because of Newton's laws of motion.

22:09So every action has an equal and opposite reaction. So it would be like sort of trying to move by kind of pushing your hands together. You know, it sort of, it doesn't, it doesn't really work, right? Yeah, right. The fan will blow onto the sail and push the sail forward, which will pull on the boat. But yet by pushing air forward, the fan gets pushed back and they're even. So the boat's getting pushed forward and back at the same doesn't go anywhere. So it doesn't go anywhere. And that is definitely true. If you do small models of this, if you kind of build versions of it to see whether what happens on a cart or whatever, instead of necessarily on water, then it's absolutely true, right?

22:46Like Newton's laws holds it's all you know no laws of physics are broken and and the boat doesn't move however Mythbusters um that amazing program with your friend Adam Savage in fact um they did a version of this where they got this like massive swamp boat which are generally driven by fans anyway and they reversed the fan round and then had it blowing into a sail and um I mean normally this boat right when it doesn't have a sail there it can go at 20 miles an hour right can kind of zip along the water um but when they had the sail and the fan it did move forward it did but only by about three miles an hour so like a really really small amount this is surprising i i'm surprised one because i've never seen this episode uh-huh which is unusual yeah and i expected something weird as soon as you started telling this story i'm like oh it must work in some way so why what was the explanation for how they're able to blow themselves forward with a fan that's on board?

23:51Okay, so there's arguments about this, right? If you want to see a couple of scientists get into a fight, ask them about aerodynamics in general, because it's really difficult to prove which force is the kind of dominant one, one way or the other. Ask a pilot about the difference between Benue and Newton, and they'll sort of descend into horror. But this is another one of those examples where basically people have gone into massive fights about it. No one is perfectly sure. But I think that the most convincing argument is that the sail doesn't just absorb the air that's being blown towards it.

24:26It ends up reflecting some of that air backwards. And so in reflecting that air backwards, then the opposite reaction is that the sail moves forwards. So that there's like an additional effect. there's a net forward force on the boat because the reflected air doesn't then get reflected back and forth and back and forth eventually it just leaves out the back yeah meaning the boat goes forward not as quickly as it would not as quickly as it would um but i mean in general okay like in general putting a fan on the same boat as a sail is like it's not a good idea eli's version is way smarter, right?

25:10Way smarter, which is that he suggests that you put a fan on a boat behind and then blow the fan in. And then now Newton's not a problem, right? You don't have to worry about equal and opposite reactions because the two things are physically separated from one another. This would totally work, right? Only slight problem about it is that a jet of air actually it sort of falls apart really quickly. You know, it doesn't sort of keep its strength very quickly. um it fans out it sort of drags other air in or still air loses its speed um and so on and so on and so uh you would have to have the the fan like absurdly close to the sail um that it's blowing and also it would have to go along with it right so your your boat with the fan on it would have to be propelled along and be like extremely close to the sail that it was following at which point you've sort of got a boat that's already moving and you may as well just use a rope instead, you know?

26:10So, I mean, in terms of the laws of physics, it's perfectly legal. Economically, unhinged, I think, is the best description of what he's come up with. But ultimately, that's my favourite category of invention. So, fine by me. It would look amazing, though, if I looked out on a lake and I saw a boat being blown by the fan in another boat, I would watch. I would love that. I'd love to see a race like that. Because of course, yeah, it becomes like hilarious because the boat with the fan on it is going to have to be using much more energy to keep up because its fan is blowing it backwards. So it's got to work even harder to move forward and keep up with the boat it's pushing.

26:52And all the energy of the actual fan itself. Yeah, I mean, it's mad. but great. Mad, but great. That should be one of the catchphrases of this podcast. Absolutely. Now, here's a question from Sever or Steve. Steve asks, Michael, in about 600 million years, the total solar eclipse era will be over. The moon will have drifted far enough from Earth that we will only experience annual eclipses. This, of course, leaves us all wondering the same thing, will the next Manhattan Hinge solar eclipse be total or annual? Okay, so I love this question because I didn't know, but I'm a huge fan of Manhattan Hinge.

27:35Manhattan Hinge is a phenomenon that was first described by Neil deGrasse Tyson. It's based on Stonehenge in England, where these stones appear to be aligned with the sun for the solstices, the winter and summer solstice. and on those dates the sun is like it's lined up on certain stones blah blah blah the details don't matter what matters is that any big monoliths could be assumed by future civilizations to also be aligned with the sun so now picture picture you are a future archaeologist it's the year 5000 and you've uncovered the the ruins these ancient ruins of new york city and you notice that of course this was a celestially important religious site because four times a year, the city aligns with the sun.