Why We Need Zip Lines On The Moon

26:47You're going to need 150 billion of them. So far, far, far less than your red blood cells, but that's still, I would say, quite a lot. These are big numbers, but they're small things. These are big numbers, but small things are great. You're also going to need white blood cells, the sort of rarer mix. You need about a couple of billion of them, barely any really, they're quite rare in comparison. and then you've got the plasma which is all the water and so on so in total all of those together you're losing about 110 grams of protein and manufacturing proteins from from raw amino acids that's that's really where the energy intensive work is going to come in so so in total that's about 500 calories and then probably an extra 150 or so um to get all of the blood glucose that you've lost the kind of cellular energy reserves the lipid bilayers so that's what you're looking at about 650 calories okay that's a lot more than i expected it is quite a lot isn't it the thing is it's spread out over a period of time so in the first 24 hours you're going to get the volume replacement that's really just where your body's going to pull water from other tissues okay um mostly to replace your lost blood plasma and then it's over the next one to four weeks which is when these blood cells start being made, that's really when you're kind of spending those 650 calories.

28:15But what I will say is they give you sort of, you know, a glass of orange juice and a biscuit to say thank you very much. You're kind of already there, really. Just on eating those, you're kind of back up to zero. Well, yeah, especially if it's sugary juice. Exactly. So how long does it take for your body to replenish everything that was donated? About four weeks. Four weeks! Yeah, which was quite a long time. Oh, man. Here's what I was thinking. If you were sitting there and instead of giving you some orange juice to drink, what if instead you sort of became a bit of a vampire and drank a pint of blood instead?

28:54Ah. Because here's what's interesting. Half a litre of blood, it might take 650 kilocalories for you to make it but it only contains about 450 calories. That is fascinating. Isn't it? So gulping down blood isn't a good way to bulk up. Gulping down blood is not a good way to bulk up. So here is what I was thinking was like okay if you I mean sure there's like that's still some good calories in there but what if you connected yourself up so you basically made yourself a sealed a sealed tube oh yeah where you were continually drinking your own blood right how would that work out probably not well the answer is definitely not well so there's a few issues here um the first is that you would you would almost certainly die from heavy metal poisoning um because a single pint of blood also contains 250 milligrams of pure iron.

29:55And if you are drinking that continually, you're going to be forcing your digestive tract to absorb these massive toxic doses of iron, which is going to overwhelm your liver. Oh, wow. So it's obviously that iron got in there naturally and healthily, but to have it so concentrated. Exactly. It's generally not a good idea. Wow. What you could do, though, is if you were if you're allowed to drink water, I'm going to assume that you're allowed to drink water. How long would it take you? You're running this calorie deficit. It takes you 650 calories to make the blood, but you're only getting 450 calories from drinking it.

30:34How long would it take you to waste away, to wither away? So we're talking here, you know, you've got your you've got your base metabolic rate as well. that's all going on um and then you've got this deficit that you're running at uh essentially i work it out as you're you're running at a deficit of about 2 190 kilocalories a day i reckon you would wither away in 87.6 days almost three months that is also longer than i expected so if you tell someone to go eat themselves it's like telling them to go die in three months yes yeah yeah now what i will say is i'm not a medical professional and i wouldn't i wouldn't i wouldn't recommend this as a way to be and it does also assume a steady supply of water okay because you're kind of losing water at every stage of this process yeah you got to replenish that but wow okay so donating blood means that over the next month you will have an extra 650 calories you're going to have to burn just to make back that blood.

31:41How often can you give blood? I think it's about every three months for men and every four months for women. Oh, interesting. It's different. I guess because if you're menstruating, presumably that comes into it too. Gosh, only every like three or four months and a pound of fat, roughly, everyone's body is different, but it takes like, that contains like 3 ,500 calories. So for your body to eat a pound of its own fat to compensate for the blood loss from the donations would take how many months? Seven times four, like 28 months, basically two years to lose a pound just by donating blood at a healthy rate.

32:22Not worth it, guys. Now, this is reminding me of a question that I'd always wondered and I finally tried to look it up this morning. And it was, you know, I don't grow hair up on top of my head anymore. And I'm like, how many extra calories am I not burning because my body isn't physically producing hair out of these follicles? Like, is that something to be, you know, worried about? And as it turns out, probably not. I found a forum on the straight dope where this user called Squink, which how can you not trust Squink? Like, Squink is like really loved this question and got obsessed with it. But the only data Squink could find was the amount of energy sheep need to grow their wool.

33:08And so Squink's conclusion is that if a person is like a sheep – well, actually, Squink is talking about beards specifically. To grow a beard for a day, just a day's worth of beard growth is only 2.28 calories. is that it that seems really low but i know our bodies are really efficient i mean if that's true then it kind of explains why when people go bald they don't suddenly go wow my my metabolism is so different that sort of feels worth it actually as i mean if you're thinking of the cost benefit analysis, right? I will pay you 2.2 calories for a day of beard. That seems worth it. Depends how much you want to have a beard, I guess.

33:59Balding is a better comparison because you can't stop growing a beard. And if you pluck or shave all your hair off, it keeps growing. You're still spending those calories every day. But once you actually go bald or have the follicles destroyed, then that's when the weight loss begins, guys. Over time, it starts to build up. Yeah. I mean, you can also shave off all your hair for like a weigh in. If you want to weigh like an ounce less, you could remove some weight that way. Speaking of which, if you look behind me, there's a Ziploc bag on the board. Let me bring this closer. Yeah. here's some of my beard hair honestly honestly michael i think i think sometimes a tour around your office you would be confused as to whether it was the office of the the great v-sauce or a serial killer but go on or both yeah it is weird but you know i shaved it all off once for charity and we had more than we needed so i'm like i can't throw this out it's like a reminder of my beard before it turned completely white, which will happen one day soon.

35:05And so I just, I just have it. When I was, I don't know, maybe about eight years old or something, I got into a big fight with my sister. And she pulled out a great big handful of my hair. And my mum, who has a sort of strange approach to punishment, she kept it in a Ziploc bag and put a little note in it saying, this is what happened on this day. And she still has it, still has this little, this handful of hair. And the two things that I've noticed in viewing it as an adult is one, my goodness me, my sister has got a good grip strength because it was an astonishing amount of hair to pull out of a child's head.

35:48But secondly, my hair colour has not changed at all my entire life. Oh, see, that's why it's so great that your mother did that. It's, that's not punishment. That's being an archivist. like I understand I've done that too I've still got my daughter's umbilical cord the little bit that like you had to wait for it to fall off and I've got clippings from her first haircut I've got the wristband that they put on to her and us at the hospital when she was born and I've given them all dates I'm trying to remember I might have like her first fingernail clipping and they're all in like envelopes in my bedside table it's like a whole you know Hannibal Lecter drawer, but it's actually beautiful.

36:29Yeah, it is. It is a life through off cuts. Yeah. Okay, should we go to a break? Let's take a break. And when we come back, I want to see this steampunk iPad.

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38:35And we are back. Hannah, you've got some kind of, I'm assuming like a mechanical calculator, but not an abacus, something in between then and now. I do have a mechanical calculator. So this was my sister gets really good gifts for me for Christmas. And this is my Christmas gift this year. And it's a thing. It's very beautiful. Look at this. So it's brass or looks like brass anyway. and it is it sort of fits in your hand and it's got a fractamator written across the top. It has feet inches and sixteenths and basically it's an addition system with a subtraction system hiding on the back. Right it's quite flat it's definitely iPad scale kind of a thing like a very thin little book, but it's made of metal and it's got grooves on it with what look like divots or something.

39:38Little holes that you can use. I cannot wait to see how this works because believe it or not, there's something similar to that at the thrift store next door to my office. And I could not figure out how to move the numbers or the pieces inside of it. Do you need to have a stylus or a pencil? A pencil. Exactly right. Okay, so I just want to sort of like picture the world at this point. So this particular one is made by a German company. They started making them in the 1920s, but these continued to be popular even after the invention of the calculator. Essentially, this is like a pre-calculator world, right?

40:17And you have to imagine that if you are doing complicated sums, so either you are an accountant and you're totting stuff up all day long, or worse you're an engineer trying to build a bridge or an aircraft actually do you know what I don't know when the actual digital calculator was invented I know that my grandparents got one I think in the early 70s they got it for free for looking at some property like real estate and they just they drove like all day just to do this tour with no intention of buying because they wanted the free digital calculator. Do you know what? Your grandparents are my kind of people, frankly.

40:59So the first electronic desktop calculator was in 1961. But as you said, they were not widely available. Texas Instruments, who are sort of the calculator kings, they weren't releasing them until the late 1960s, 1970s. So we're talking about there are sputnik is in space we've got you know attempts to get to the moon while people are running the calculations on all of the orbits on how to build everything they're running them on these kind of things here these like these mechanical systems where uh there's no electronics involved right when you stop to think about it they're like constructing nuclear bombs with mechanical calculators they're sending people into space with mechanical calculators just they're discovering general relativity and quantum mechanics with mechanical calculators this is just wild to me i can't even i can't even do five times eight anymore without checking your electronic calculator yeah show me show me how this works okay let me show how it works all right so this particular one the fractometer uh the thing that makes this special and the thing that made it outlast electronic calculators is because it can handle fractions of an inch okay so if you go run along top here so this is all about distance can you use this for simple addition and subtraction or is it for working within the imperial system of feet and inches so you can use it for integer addition and subtraction if you want to but when it comes to the decimal points then you're then then you're locked into the imperial system.

42:49Okay. So let me show you like an additional, a really straightforward addition on this. Okay. So what you do, so for those of you who are listening, let me try and describe what you're looking at here. So you have, you've got this panel of numbers and they're arranged as you might expect. So you've got some units, tens, hundreds, et cetera, et cetera, et cetera. And then over to the far right-hand side, you have inches and then you have fractions of an inch right over on the far right hand column. Okay, so if you want to add, the thing is if you just want to add, let's go here, right? So in the ones column, if you want to add, say, four, so you slide it down to the number four, you see the number four appears here.

43:32Right, you've stuck your pencil into the hole for the number four and you've dragged an internal rail downwards. Exactly. So if you want to do something simple like four plus two i've done the four and then i can do the exact same process for two i put my pencil in the two and i drag it down and then you've moved the internal mechanism six spaces okay that's really super easy where things become difficult is when you take a number that then requires you to carry over into the next column this has always been the thing that makes it tricky so what you do in that case so i now have six uh if i want to add a number to six let's say you want want to add eight to six instead of going down you go up and over which effectively moves this block moves the block that you were originally in by um eight spaces but it also carries over to the following column so it's like you're effectively like minusing two from this column and adding 10 to the next and it's doing it all simultaneously And so this is the bit that makes this super clever is that you can, rather than the rail just going up and down and up and down, when you carry over, your pencil physically moves the next column of units.

44:59Right. I was wondering why they had that candy cane shape. And it's because you have to go up and then drag over to notch one more on the next place. So the slider that you're sticking your pencil into, it's mainly silver, but eventually you start seeing red numbers. And if it's red, you need to pull up, I guess, is the rule. Exactly. Because adding eight is the same as saying minus two plus ten. Or minus two to this column, add one to the following column. This is why I think devices like this should be in schools. not because I love old-fashioned things, but because it shows you how numbers work with each other and what the goal is and the different ways to get there.

45:47When you just are taught, memorize five times eight or memorize this particular strategy for multiplying two-digit numbers, it just becomes, I don't know, like you do it by rote and you don't go, ah, place value matters and I get why we're carrying over. whatever. Yeah, because you are literally carrying it. I mean, you're physically carrying it over to the next column. I think that's exactly right. Exactly right. That you get this kind of intuitive physical feeling for it that you don't get when you're just dealing with an electronic calculator alone. The really nice thing about this one. So all of these where you're in the feet columns, you're just going one to 10.

46:28So this is all makes perfect sense. Because it's in imperial, once you get over to the inches it no longer is one to ten or not to nine i should say it suddenly becomes not to eleven in the inches column right it still allows you to carry over but it takes into account the fact that there are 12 inches in a foot right so it's the 12th that moves into the next place the next column quite right when you're over here on the 16th of an inch this is where it has an advantage if you have if you're having to deal in feet and inches and sixteenths of inches and so on all the time in imperial metrics and you're building bridges and whatnot this is where this has an advantage to an electronic calculator because let's say that you want to do okay three eighths of an inch hang on let me let me do a little reset clear all thank you oh it shows how it resets it's got a little like bar on top it does have a little bar and you pull it up and it resets all of the numbers.

47:26Isn't that cute? I love that. So let's say that you had three eighths of an inch and you wanted to add to it 11 sixteenths of an inch. If you're doing it on a calculator you first got to convert everything to sixteenths. You got to add it up. It's just it gets a bit complicated. Then you've got the imperial to metric conversion or sorry the imperial to decimal conversion. It just it's all really complicated but with this situation you can just go, okay, actually it's just 15 16ths. Easy peasy. That's really nice. So these actually, as I say, lasted on in time. These were still being used well into sort of late 70s, early 80s, just because they had this advantage to it.

48:11I wanted to ask how subtraction works. Do you just reverse the rule? You move silver up and you move red down? Don't just reverse the rule, my friend. You reverse the side. What? It's the exact same internal mechanism. It's just you're moving it up on one side, down on the other effectively. It's flipped over. Right. So you don't need a new thing. You can just add and subtract, add and subtract, and it can tally the entire thing as you go. So you could be adding some things together, flip over, subtract them. So you flip it over. It's got the answer you currently have, the running total, and then you can start subtracting from it on the other side.

48:48Exactly. That's beautiful. Isn't it gorgeous? and this is the thing okay so um just going back to the point that you made earlier about how having these old school mechanical objects actually give you a much more intuitive feel for what the numbers are actually doing even when you're doing simple things like addition and subtraction and multiplication i think the same thing of good old-fashioned slide rules You know, we're in boomer tech now. I love a good slide rule, but I love no slide rule more than the slide rule, Michael, that also happens to be a pair of chopsticks, which was a gift from you.

49:29Look at those. They look familiar. Yeah, we designed those and they were in a curiosity box a couple of years ago. And yeah, you can eat some food with your chopsticks, but then they also slide by each other and you can do slide rule calculations. You can do addition, subtraction, multiplication, division, as well as exponents. Yeah, to the power of two, to the power of three. We don't have time to go through it today, but learn how a slide rule works. Learn how that kind of, what the heck is that thing that you, what's it called in general, what you brought today? It's a mechanical calculator, but is it called like a slider or a...

50:05This one is called an adiator. Ah, yes. A slide calculator, also known as an adiator after the best known brand. So the generic is slide calculator. I don't want the adiator people coming after us. They're their competitors. But the point is that learning how these work gives you such a much deeper understanding of number theory. It's amazing. The reason why I think slide rules are really interesting is because they use this mathematical trick to make multiplication way easier. The thing that makes these unusual, the slide rule and the adiator, is that they're not using any turning because most mechanical calculators would be based on a system of cogs where you would have one cog that would turn and turn and turn and turn and turn and then on the 10th would flip the next cog.

50:55That was sort of how they managed to handle carrying over a digit effectively. And there are all kinds of these that exist at various levels of complexity. One of them, which I think is probably the most beautiful, is called a kurta. And these things, they get found in people's lofts, like stashed away in the stuff your grandparents owned, thinking they often get sort of chucked away really because people think that they're musical boxes that don't work anymore. But they look like an old fashioned sort of pepper mill. They have a handle on top that you can turn around to do the calculations. Like a pepper mill, yeah.

51:31Like a pepper mill, exactly. I know, I've seen videos about them and I want one so badly, but look on eBay, they're all over$1 ,000. Over$1 ,000. They're wildly expensive. And fair play because they are an unbelievable masterclass in precision engineering. But the story about these kurters is that it was actually invented by a prisoner of war during the Second World War, Nazi prisoner of war. and were it not for his clear talents in this area of engineering, then he almost certainly would have been murdered. But instead he managed to escape the camps and after the war launched this brand and it was one of the most popular mechanical calculators for a number of decades.

52:20I want one of those so bad. I want one so bad. All right, I'll put that on the Christmas list for Hannah. mechanical calculator. The fractometer, by contrast, I think is worth about 20 quid. Yeah, I was going to say the slide calculator next door is$3. Yeah. Buy it though. I want to see a picture of it. Yeah, I'll see if I can find it. You've inspired me though. I think I'm going to go and play with that with my kids. I was in the House of Lords last week talking about adult numeracy. This is the kind of stuff I do on days when I'm not with you, Michael. and they were saying, how can we improve numeracy in young people and adults in the general population?

53:01And it's really hard. But I think that you're right, that actually having a physical connection when you're manipulating numbers is one of the really good ways to do it. Well, yeah, I'm sure you've seen people build those mechanical counters that go up with binary and like that shows how binary works so much better than reading the Wikipedia page. and you can build calculators with falling marbles and just little levers in the same way in base 10. And your understanding of what the heck numerals and our notation or what a place value system, what that means, it makes everything so much clearer.

53:40I have a book that is, I haven't read it yet, but it's one of my ideas for like a long video in the future. And it's a book of all the different ways there are to multiply numbers. and add them and subtract them. And by that, it means all the methods. And in school, you usually learn the method that your country at the time has said, this is what we should teach. So for like me multiplying, we did the whole like, okay, so you start at the ones digit and you go to the ones times the ones, the ones times the tens, and you label them out and add them up. But then you see these viral TikToks about in Japan, they use diagonal lines.

54:15And in China, they use dots or whatever. And everyone goes, what? Math should only go one way. And it's like, no, these are the methods for working with numbers. Sometimes it's more convenient to do it one way, sometimes the other. But if you learn them all, you suddenly are like a wizard of numbers. I have a similar book downstairs, actually. It's Speed Arithmetic Techniques. Ooh. As you can tell by the fact that I need you to calculate it to do four times eight, I haven't read it. But one day, Michael, one day I'm going to read it and then I'm going to blow you away. Oh, yeah. I fell down a rabbit hole of watching a like math, a speed math person on Instagram or something.

54:56And I loved it because the guy was using very different methods. He was like, don't do the whole thing you learned in school. Like just take every number and break it apart. 72 times 48. You can do 70 times 40 really quickly. And you can do two times eight really quickly. And then adding them together in your mind, way easier to do mentally. Do you know what? I think we should do another Field Notes episode where we just shout numbers at each other. Yes. I do definitely think an episode on like mental math tricks could be useful. Like there are some, you know, like finding the square roots of certain numbers can actually be really easy.

55:33Squaring numbers and cubing them, there are shortcuts. And then the listeners will walk away going, hey, name a four digit number. I can find its cube root in like a second and your life will be the same. Okay, well, you can write to us and tell us if that is an episode that you would like to hear or the I'm very idea if it horrifies you. As ever, send us anything you would like us to answer to therestiscience at gohanger.com. Yes, please do. And join our newsletter at therestis.com slash science. Until next time, stay curious. Bye.

56:15Thank you.