WEBVTT - The Pressure 0:00:00.160 --> 0:00:04.840 My welcome Stuff to Blow Your Mind, a production of 0:00:04.880 --> 0:00:13.880 I Heart Radios How Stuff Works. Hey, welcome to Stuff 0:00:13.880 --> 0:00:15.960 to Blow your Mind. My name is Robert Lamb, and 0:00:16.000 --> 0:00:18.799 I'm Joe McCormick. Robert. There's a kind of mistake we 0:00:18.840 --> 0:00:21.959 all make in our modern electrified homes, and this is 0:00:22.000 --> 0:00:27.400 microwave mistakes. What's the worst microwave mistake you've ever made? Oh? Um, 0:00:27.440 --> 0:00:30.520 I don't know about the worst. I mean, generally it 0:00:30.520 --> 0:00:33.600 just involves megan a mass like splat splattering something, not 0:00:33.680 --> 0:00:37.240 covering something appropriately, so you have to not only remove 0:00:37.280 --> 0:00:39.360 your food from the microwave, but then scrub it out. 0:00:39.520 --> 0:00:42.440 I remember there was one day not too long ago. 0:00:42.520 --> 0:00:44.200 I think it might have been like on New Year's 0:00:44.280 --> 0:00:47.080 this year or something that within the same day, I 0:00:47.080 --> 0:00:49.920 think I tried to microwave butter to melt it and 0:00:50.000 --> 0:00:52.800 it exploded in the microwave. But then I also tried 0:00:52.840 --> 0:00:56.279 to microwave a soft boiled egg to heat it up 0:00:56.360 --> 0:00:59.160 and it exploded. Uh so, I don't know. There's a 0:00:59.200 --> 0:01:01.680 lot of exploding the microwave. But there's another kind of 0:01:01.760 --> 0:01:05.800 microwave mistake where we use this radio range of ultramodern 0:01:05.880 --> 0:01:09.280 convenience uh to to maybe maybe do a little less 0:01:09.560 --> 0:01:12.480 troublesome damage than than blowing up an egg, but at 0:01:12.520 --> 0:01:16.440 least causing frustration. When you warp lids of containers in 0:01:16.480 --> 0:01:20.000 the microwave. You've ever done this? Uh? So you know 0:01:20.040 --> 0:01:21.600 you want to heat up some food, maybe you just 0:01:21.640 --> 0:01:23.880 want to sterilize a bowl full of mud or something, 0:01:23.959 --> 0:01:25.920 So you put it in a glass bowl with a 0:01:26.000 --> 0:01:29.240 tight fitting lid or you know, tight fitting plastic, tight 0:01:29.280 --> 0:01:32.520 fitting rubber lid. Uh. You know you maybe shouldn't do this, 0:01:32.560 --> 0:01:34.679 but you forget, but you cover it up with something 0:01:34.720 --> 0:01:37.319 that fits tight, and you microwave it and it gets 0:01:37.319 --> 0:01:39.600 piping hot, and you leave it standing in the microwave 0:01:39.640 --> 0:01:41.760 for a minute, and then when you check it, the 0:01:41.840 --> 0:01:44.240 lid or the plastic wrap or whatever you've used to 0:01:44.280 --> 0:01:47.840 cover it has been sucked down into a concave depression 0:01:47.920 --> 0:01:50.440 over the food. It has turned your you know, if 0:01:50.480 --> 0:01:52.880 it's a permanent lid, it has warped it maybe or 0:01:53.240 --> 0:01:55.640 you've caused trouble. And the way we normally think about 0:01:55.680 --> 0:01:58.440 these kind of things is that when something like this happens, 0:01:58.480 --> 0:02:02.560 the lid or the plow stick was sucked down. But 0:02:02.680 --> 0:02:06.440 think about why is that happening. What's actually happening there? 0:02:06.480 --> 0:02:10.400 What's the attractive force pulling the lid of the container 0:02:10.520 --> 0:02:14.360 down into the food? Obviously it's not gravity, right, The 0:02:14.400 --> 0:02:17.560 food isn't like a star pulling things into its orbit. 0:02:18.040 --> 0:02:22.480 And it's not electromagnetism. The food isn't a magnet attracting 0:02:22.520 --> 0:02:25.800 an opposite charge. It's not like the strong force that 0:02:25.840 --> 0:02:29.200 holds atomic nuclei together. So what's the attraction there? So 0:02:29.160 --> 0:02:33.000 superdnse potatoes are out of the question. No, though those 0:02:33.040 --> 0:02:35.640 can be a big problem. That's why when you make 0:02:35.639 --> 0:02:37.919 a big potato, fun fact, you should cut it open 0:02:38.000 --> 0:02:39.639 right after you pull it out of the oven. Don't 0:02:39.680 --> 0:02:45.000 leave it to sit there forever it turns into a rock. No. Counterintuitively, strangely, 0:02:45.200 --> 0:02:49.280 what's happening when that lid gets pushed down is the 0:02:49.360 --> 0:02:53.600 atmosphere pressing on it. When the lid bends, what you're 0:02:53.639 --> 0:02:57.240 witnessing is the weight of the air we breathe. And 0:02:57.320 --> 0:02:59.680 it's a powerful Wait, it really is, but we don't 0:02:59.720 --> 0:03:03.480 norm normally notice it. Like, how come the atmosphere only 0:03:03.560 --> 0:03:06.640 pushes a depression into the lid after it's been microwave? 0:03:06.720 --> 0:03:09.000 Why doesn't the atmosphere, bend the lid when it's just 0:03:09.040 --> 0:03:11.720 sitting on the counter at room temperature. One thing you 0:03:11.800 --> 0:03:14.320 might be thinking is, okay, maybe it heats the lid 0:03:14.440 --> 0:03:16.600 up and this like sort of melts it or something 0:03:16.680 --> 0:03:19.080 and makes it more appliable. But no, that that's not 0:03:19.120 --> 0:03:22.919 necessarily the case. It's because of the power of condensation. 0:03:23.760 --> 0:03:27.280 After you microwave a bowl of food containing water, a 0:03:27.280 --> 0:03:29.680 lot of the water in that food is turned into 0:03:29.760 --> 0:03:33.040 steam or water vapor. And of course when liquid is 0:03:33.040 --> 0:03:35.280 turned into a gas, it not only becomes hot, but 0:03:35.360 --> 0:03:38.280 it expands. It takes up more space, and it expands 0:03:38.320 --> 0:03:41.640 to fill evenly all the space it can. So the 0:03:41.680 --> 0:03:45.040 spots inside the sealed bowl are not occupied that are 0:03:45.080 --> 0:03:47.960 not occupied by food, they get filled with hot, high 0:03:48.040 --> 0:03:51.000 pressure steam. And of course we know one thing that 0:03:51.040 --> 0:03:53.800 can happen here as as water turns to steam inside 0:03:53.800 --> 0:03:56.440 a sealed container is it can make the container explode. 0:03:56.440 --> 0:03:58.640 In some cases, that's what happened I think with my egg, 0:03:59.200 --> 0:04:01.520 Like the yolk is turning to steam and it had 0:04:01.560 --> 0:04:03.920 to expand, and so the egg blew up. But if 0:04:03.960 --> 0:04:07.760 your container doesn't expand, it just fills with high pressure steam. 0:04:07.800 --> 0:04:10.960 And then when the microwaving stops, the contents of the 0:04:10.960 --> 0:04:14.000 bowl cool down again. And what happens, well, the steam 0:04:14.040 --> 0:04:17.040 that had filled all these voids in the bowl starts 0:04:17.040 --> 0:04:20.880 to lose energy, it cools down, it gradually converts back 0:04:20.920 --> 0:04:24.000 into liquid water. And this process, of course, is known 0:04:24.040 --> 0:04:27.000 as condensation. It's the same reason that dew forms on 0:04:27.000 --> 0:04:29.360 the outside of your cold soda can on a warm day. 0:04:29.400 --> 0:04:33.320 The cold can is converting water vapor in the air 0:04:33.520 --> 0:04:36.040 into liquid by cooling it. But if the bowl in 0:04:36.080 --> 0:04:38.599 the microwave has a tight fitting lid, or it's wrapped 0:04:38.640 --> 0:04:41.480 tightly in plastic, what happens when the water converts from 0:04:41.480 --> 0:04:44.200 a gas back into a liquid while it takes up 0:04:44.320 --> 0:04:47.799 less space and it exerts less pressure on the inside 0:04:47.800 --> 0:04:51.320 of the bowl. Thus, a covered bowl becomes a low 0:04:51.400 --> 0:04:55.440 pressure environment or a partial vacuum. Without air pushing back 0:04:55.480 --> 0:04:57.920 at the same pressure on the lid from below. The 0:04:57.960 --> 0:05:01.320 atmosphere leans hard on the it and it presses it 0:05:01.400 --> 0:05:05.839 down into the evacuated space, the vacuum, punching it into 0:05:05.880 --> 0:05:08.720 that bowl shape. So what you're seeing when the when 0:05:08.720 --> 0:05:11.960 the lid bends down is the footprint of the atmosphere, 0:05:12.240 --> 0:05:14.800 and of course The reason the lid doesn't normally warp 0:05:14.839 --> 0:05:17.040 informa bowl when it's sitting on the counter or whatever 0:05:17.160 --> 0:05:19.800 is that the pressure is equalized on both sides. There's 0:05:19.800 --> 0:05:23.080 atmosphere below it as well. The partial vacuum created by 0:05:23.080 --> 0:05:27.240 the condensation of steam changes. That evacuates the space in 0:05:27.279 --> 0:05:30.080 the bowl as the steam condenses into water, and then 0:05:30.120 --> 0:05:32.880 the atmosphere comes in. And this is such a This 0:05:33.000 --> 0:05:36.640 a wonderful, mundane little way of seeing something strange and amazing. 0:05:36.920 --> 0:05:41.800 The power of atmospheric pressure. Yeah, you know it, you know. Normally, 0:05:41.800 --> 0:05:44.080 when I observed this, my main thought is, oh, I 0:05:44.080 --> 0:05:46.560 hope I don't break the plastic top to my glass 0:05:47.040 --> 0:05:50.279 of food storage container, because I'm down to like one 0:05:50.360 --> 0:05:55.480 plastic top. They're all eight glass containers. But but yeah, this, 0:05:55.480 --> 0:05:56.960 this is an interesting way of looking at it, to 0:05:57.000 --> 0:06:00.800 see it as the footprint of the atmosphere, the weight 0:06:00.800 --> 0:06:04.320 of air actually observed. It's funny how it can be 0:06:04.480 --> 0:06:07.080 so powerful and we're so blind to it most of 0:06:07.080 --> 0:06:09.920 the time. I want to tell a related story about 0:06:09.960 --> 0:06:12.719 a about a seventeenth century Prussian mayor. How about we 0:06:12.760 --> 0:06:16.760 go there. Okay, so this guy is named Otto von Garica. 0:06:17.000 --> 0:06:19.520 He lived from sixteen o two to sixteen eighty six. 0:06:19.640 --> 0:06:22.960 And uh. In addition to being a lawyer and a politician, 0:06:23.080 --> 0:06:25.440 he was, as I said, a mayor. He was an 0:06:25.440 --> 0:06:28.360 important engineer and physicist in history, and he had all 0:06:28.480 --> 0:06:31.919 kinds of scientific accomplishments. For example, in the sixteen sixties 0:06:32.240 --> 0:06:34.760 he invented what is believed to be the world's first 0:06:34.880 --> 0:06:40.080 known electrostatic generator, which is a device for generating electrical potential. Now, 0:06:40.240 --> 0:06:42.679 we talked a bit, you remember, Robert, about the history 0:06:42.680 --> 0:06:45.960 of electrostatic generators on the I think it was the 0:06:45.960 --> 0:06:50.160 episode about the electric arc thesis, right, Yes, I believe so. Yeah, 0:06:50.200 --> 0:06:53.560 But for a brief refresher, these early generators were generally 0:06:53.720 --> 0:06:56.279 based on friction, kind of like how you can build 0:06:56.320 --> 0:06:59.200 up an electric charge on yourself by scuffing around on 0:06:59.240 --> 0:07:02.600 a carpet. Von Garrika discovered that he could build up 0:07:02.600 --> 0:07:05.960 a charge on a ball of sulfur if he rotated 0:07:06.000 --> 0:07:09.280 it rapidly with a crank to rub against things. And 0:07:09.360 --> 0:07:11.680 he eventually discovered that building up a charge in this 0:07:11.680 --> 0:07:14.600 way could cause the sulfur ball to glow in the dark. 0:07:15.120 --> 0:07:18.640 But this wasn't Von Gerrika's only cool invention. Demonstrating like 0:07:18.720 --> 0:07:22.280 the potential of vast hidden powers in the world. He 0:07:22.360 --> 0:07:25.840 was also interested in the power of vacuums and voids, 0:07:25.880 --> 0:07:28.280 and in the weight of the atmosphere, which, as we 0:07:28.280 --> 0:07:31.280 were just saying, usually goes unnoticed by us. So Von 0:07:31.360 --> 0:07:34.600 Garrika was the mayor of a city called Magdeburg, and 0:07:34.680 --> 0:07:37.800 around sixteen forty nine or sixteen fifty or so he 0:07:38.000 --> 0:07:41.680 invented the first known air pump which could be used 0:07:41.720 --> 0:07:45.520 to remove gas from a closed container. And by using 0:07:45.520 --> 0:07:48.520 this pump to create a partial vacuum, he was able 0:07:48.560 --> 0:07:51.120 to conduct fascinating research on the nature of voids in 0:07:51.200 --> 0:07:55.240 empty space. For example, he discovered that light could pass 0:07:55.280 --> 0:07:58.760 through a vacuum, but sound could not, and like so, 0:07:58.840 --> 0:08:02.040 given what was known the in the sixteen fifties, how 0:08:02.080 --> 0:08:05.360 could that be? You know what? What was causing that fascinating? 0:08:05.600 --> 0:08:08.320 But then also in a series of public experiments following this, 0:08:08.760 --> 0:08:11.800 he demonstrated the power of a vacuum, or more precisely, 0:08:11.840 --> 0:08:15.040 the power exerted on a vacuum by air pressure, in 0:08:15.120 --> 0:08:18.280 a really awesome way, with an experimental apparatus that came 0:08:18.320 --> 0:08:22.120 to be known as the Magdeburg hemispheres. So Von Garica 0:08:22.200 --> 0:08:25.440 had this air pump of his and he created two 0:08:25.520 --> 0:08:31.480 precisely fitted copper hemispheres to like hollow half spheres that together, 0:08:31.680 --> 0:08:33.720 if you fit them together, they would make a closed 0:08:33.760 --> 0:08:35.800 hollow sphere that was about thirty five and a half 0:08:35.800 --> 0:08:39.600 centimeters in diameter. And these spheres were constructed with a 0:08:39.720 --> 0:08:42.199 valve so that they could when they were pressed together 0:08:42.240 --> 0:08:45.600 to create an enclosure. Varna could attach his air pump 0:08:45.679 --> 0:08:48.040 to the valve to force the gas out of the 0:08:48.040 --> 0:08:52.120 hollow sphere and create a partial vacuum inside. And here's 0:08:52.160 --> 0:08:54.840 the mind blowing part. Once the gas had been pumped 0:08:54.880 --> 0:08:58.000 out of the space between the two hemispheres, these copper 0:08:58.040 --> 0:09:01.120 domes could not be pulled apart, even when they were 0:09:01.120 --> 0:09:04.920 tied to horses pulling them in opposite directions. And yeah, 0:09:05.080 --> 0:09:06.880 it's and I want to be clear, like, there's no 0:09:06.960 --> 0:09:10.560 device holding the two hemispheres together. They weren't glued or 0:09:10.640 --> 0:09:13.400 latched together or anything. You just press them together with 0:09:13.480 --> 0:09:16.240 a relatively air tight seal, pump the air out of 0:09:16.280 --> 0:09:19.720 the middle, and they stay so stuck together that even 0:09:19.880 --> 0:09:23.560 horses pulling at each end couldn't separate them. So we 0:09:23.600 --> 0:09:26.600 ask again, what's holding these half spheres together, just kind 0:09:26.600 --> 0:09:29.680 of like what's pulling the lid of the microwave container down, 0:09:30.440 --> 0:09:32.720 just as was the case with the bull in the microwave. 0:09:32.800 --> 0:09:36.560 If you're imagining some force inside the spheres sucking them together, 0:09:37.000 --> 0:09:39.920 that's not accurate. There is no real sucking in a way, 0:09:40.000 --> 0:09:42.040 sucking is an illusion which you know there'll be a 0:09:42.120 --> 0:09:46.520 good motivational poster almost um. The real force here was 0:09:46.679 --> 0:09:49.600 the weight of the atmosphere, the pressure difference between the 0:09:49.679 --> 0:09:52.400 outside of the sphere and the inside. So you can 0:09:52.440 --> 0:09:57.200 sort of imagine the Earth's atmosphere reaching down with two huge, 0:09:57.320 --> 0:10:01.719 invisible fingers and pressing the two hemispheres together while the 0:10:01.760 --> 0:10:04.080 horses tried to pull them apart. And to separate the 0:10:04.080 --> 0:10:08.680 spheres you would have to overpower that push of the atmosphere. Now, 0:10:08.679 --> 0:10:10.520 of course, an easy way to separate them is just 0:10:10.600 --> 0:10:13.360 to just open the valve and allow the air to 0:10:13.480 --> 0:10:15.920 fill the sphere um and then of course they'd come 0:10:15.960 --> 0:10:18.800 apart instantly because the pressure pushing out from the inside 0:10:18.800 --> 0:10:21.240 would be the same as the pressure pushing in from 0:10:21.240 --> 0:10:24.720 the outside. And that I love these kind of experiments, 0:10:24.760 --> 0:10:29.199 the kind that suddenly demonstrate in sharp relief amazing forces 0:10:29.240 --> 0:10:32.520 that are always there. They're always present, but they're invisible 0:10:32.520 --> 0:10:35.160 to us from moment to moment. An atmosphere pressure is 0:10:35.240 --> 0:10:37.920 like this, it's our whole world. We spend our whole 0:10:38.040 --> 0:10:41.000 lives in it. We evolved in it, we're adapted to it. 0:10:41.000 --> 0:10:44.360 It permeates our bodies, so we don't feel or notice it. 0:10:44.360 --> 0:10:47.240 It's just completely invisible to us. But if you merely 0:10:47.280 --> 0:10:51.800 create a vacuum inside two half spheres, the familiar becomes 0:10:51.800 --> 0:10:54.840 strange again, and these fingers of the atmosphere come pressing 0:10:54.880 --> 0:10:58.520 down and the sky becomes so heavy it's kind of frightening. Well, 0:10:58.559 --> 0:11:02.199 let's break things down a little bit into about pressure itself. 0:11:02.640 --> 0:11:06.439 What is pressure? Well, pressure is actually fairly simple. Has 0:11:06.480 --> 0:11:09.720 two components. It has force, and it has an area 0:11:09.800 --> 0:11:11.839 over which that force is applied. And this is why 0:11:11.880 --> 0:11:15.520 you often hear pressure explained in terms of like pounds 0:11:15.520 --> 0:11:19.640 per square inch. Right, So pressure is not Pressure is 0:11:19.679 --> 0:11:22.640 not just the amount of force pressing on something, but 0:11:22.960 --> 0:11:25.400 where that force is being applied. So one way of 0:11:25.440 --> 0:11:28.360 thinking about this is like, why do so many weapons 0:11:28.400 --> 0:11:31.199 have sharp points and blades or not just weapons, I 0:11:31.240 --> 0:11:33.800 mean any kind of like piercing object it's because they 0:11:33.840 --> 0:11:36.679 take the force of your swing or thrust or push 0:11:37.040 --> 0:11:40.000 and they apply it to a smaller surface area, increasing 0:11:40.000 --> 0:11:43.319 the pressure on that surface area and usually doing more 0:11:43.400 --> 0:11:47.000 damage or getting through what you're trying to separate. Now, 0:11:47.080 --> 0:11:51.640 when we start then up applying this to Earth's atmosphere, uh, 0:11:51.720 --> 0:11:54.560 it really gets fascinating. Uh. And this is a topic 0:11:54.600 --> 0:11:57.440 I I really enjoyed researching several years back when I 0:11:57.480 --> 0:12:01.000 wrote a piece called How Weather Works for How Stuff Works, 0:12:01.000 --> 0:12:04.720 probably one of my favorite articles that ever worked on UM. 0:12:04.760 --> 0:12:06.440 And one of my sources on that was a book 0:12:06.440 --> 0:12:10.400 called The Atmosphere Planetary Heat Engine from twenty from two 0:12:10.440 --> 0:12:15.280 thousand and seven by Gregory L. Vault and so member 0:12:15.559 --> 0:12:18.240 some of these figures are his figures, I believe from 0:12:18.280 --> 0:12:22.760 that book. But UM, the Earth's atmosphere, if you were 0:12:23.000 --> 0:12:25.679 to weigh it, it would weigh in at a whopping 0:12:25.920 --> 0:12:31.560 five point five quadrillion tons. That's a fourteen zeros trailing 0:12:31.600 --> 0:12:34.280 after it. So you know that's that's a lot of mass. 0:12:34.480 --> 0:12:37.120 And it's actually it's the driving force behind air pressure. 0:12:37.720 --> 0:12:40.360 So one one analogy that I kind of like to 0:12:40.400 --> 0:12:42.280 turn to here is like if you imagine a squad 0:12:42.360 --> 0:12:46.280 of cheerleaders forming a human pyramid. The cheerleaders on the 0:12:46.280 --> 0:12:48.280 bottom have to bear the weight of all the other 0:12:48.480 --> 0:12:51.320 cheerleaders on top of them, while the cheerleader on the 0:12:51.320 --> 0:12:53.400 top doesn't have to bear, you know, any of the weight. 0:12:54.600 --> 0:12:57.560 A similar situation exists in the atmosphere. The air is 0:12:57.840 --> 0:13:00.160 least pressurized at the edge of space, where it's a 0:13:00.160 --> 0:13:03.320 little or nothing pressing it down. The air at sea level, however, 0:13:03.400 --> 0:13:05.079 is weighed down by all the air on top of it. 0:13:05.400 --> 0:13:08.840 Um like those pool poor cheerleaders shoring up the pyramid. 0:13:09.520 --> 0:13:12.200 All this pressure presses the molecules in the lower atmosphere 0:13:12.200 --> 0:13:14.760 closer together, and that means that the higher the air pressure, 0:13:14.920 --> 0:13:18.240 the greater the air density. And for this reason alone, 0:13:18.360 --> 0:13:21.920 fifty of Earth's air exists below an altitude of three 0:13:21.960 --> 0:13:25.000 miles or five kilometers, right. And that's one reason it 0:13:25.040 --> 0:13:27.560 actually becomes kind of difficult to say exactly where the 0:13:27.600 --> 0:13:31.000 atmosphere stops, right, because the atmosphere doesn't there's not like 0:13:31.040 --> 0:13:33.720 a dividing line where it stops. We've kind of imposed 0:13:33.760 --> 0:13:36.719 some arbitrary dividing lines where we say, well, conventionally the 0:13:36.800 --> 0:13:39.560 atmosphere stops here, but it just keeps getting thinner and 0:13:39.600 --> 0:13:42.320 thinner until you go up until you basically realize, well, 0:13:42.360 --> 0:13:44.679 I guess I would call this empty space. Yeah, that's right. 0:13:44.679 --> 0:13:47.560 There's not like a membrane or anything up there. So 0:13:47.720 --> 0:13:51.760 standing at sea level, the atmosphere exerts, on average, a 0:13:51.800 --> 0:13:55.880 pressure of fourteen point seven pounds or six point seven 0:13:55.960 --> 0:13:59.679 kilograms against every square inch of your skin. Now, I've 0:13:59.679 --> 0:14:03.679 also seen this figure slightly differently before the National Oceanic 0:14:03.720 --> 0:14:07.800 and Atmospheric Administration. Uh they say fourteen point five pounds 0:14:07.800 --> 0:14:10.600 per square inch, and uh per square inch it's p 0:14:10.760 --> 0:14:12.800 s I. So when you hear say P s I later, 0:14:12.840 --> 0:14:15.880 that's what we're referring to. I find this interesting to 0:14:15.920 --> 0:14:18.480 think about. Okay, fifteen pounds per square inch again that 0:14:18.520 --> 0:14:21.440 we just totally take for granted. And I know each 0:14:21.520 --> 0:14:27.120 of us recently acquired a fifteen pound gravity blanket. This 0:14:27.200 --> 0:14:29.040 is not a paid plug, not a paid plug, but 0:14:29.080 --> 0:14:31.800 just to to illustrate, it's a blanket the ways fifteen 0:14:31.840 --> 0:14:34.960 pounds and you pull it over your body and it 0:14:35.040 --> 0:14:38.240 presses down on you and this kind of like uh 0:14:38.920 --> 0:14:42.880 comforting in human hug and uh So when I was 0:14:42.920 --> 0:14:45.720 researching this, and I was adding that into my notes 0:14:45.720 --> 0:14:47.440 about the fifteen pounds, I was like, oh my goodness, 0:14:47.480 --> 0:14:50.320 I gotta I gotta bust the gravity blanket out and 0:14:50.320 --> 0:14:53.600 and feel what fifteen pounds feels like, or rather what 0:14:53.720 --> 0:14:56.480 fifteen additional pounds feels like. Yeah, but there's one of 0:14:56.520 --> 0:15:00.360 those for every square inch of your body. Yeah. Yeah, 0:15:00.360 --> 0:15:02.800 So it's it's crazy to think about that. Now we've 0:15:02.840 --> 0:15:06.000 already sort of explored this, but you you might begin 0:15:06.040 --> 0:15:08.720 to wonder about Okay, so there's a lot of square 0:15:08.720 --> 0:15:12.240 inches on my body, uh, and fifteen pounds alone that 0:15:12.280 --> 0:15:15.240 can start to feel pretty heavy, even distributed just over 0:15:15.280 --> 0:15:17.760 the entire thing in a gravity blanket. How come I 0:15:17.800 --> 0:15:21.560 don't feel just constantly weighed down by the atmosphere. Why 0:15:21.600 --> 0:15:25.120 isn't it a crushing force that prevents me from doing anything? Well, 0:15:25.240 --> 0:15:26.680 I guess there's kind of like two answers to that. 0:15:26.720 --> 0:15:29.600 I mean, one is this is the norm, this is 0:15:29.640 --> 0:15:33.040 what you are used to. And then there's also you know, 0:15:33.360 --> 0:15:35.480 I've I've seen it written. You know that basically you're 0:15:35.520 --> 0:15:37.160 the fluids in your body are pressing out with the 0:15:37.200 --> 0:15:41.960 same force, so everything is there's equilibrium there, right, we 0:15:42.040 --> 0:15:45.080 are at equilibrium in this pressure. It's what our bodies 0:15:45.120 --> 0:15:48.040 are evolved to existent. If you brought in, you know, 0:15:48.320 --> 0:15:51.840 an alien from outer space that I was living, I 0:15:51.840 --> 0:15:54.320 don't know. I was living in a super low pressure environment. 0:15:54.440 --> 0:15:56.720 That's how its body had been formed, and then you 0:15:56.800 --> 0:15:58.480 brought it to the surface of Earth, it might well 0:15:58.520 --> 0:16:01.120 be crushed like a like a tin can a right, 0:16:01.160 --> 0:16:03.920 and then there might be issues with with the density 0:16:04.120 --> 0:16:06.440 because one of the issues too, is that if you 0:16:06.520 --> 0:16:10.200 venture above sea level air pressure uh, and it's corresponding 0:16:10.240 --> 0:16:13.400 density will decrease. That's why it's more difficult to breathe 0:16:13.400 --> 0:16:16.080 a higher altitudes. Yeah, that's why it would be you know, 0:16:16.400 --> 0:16:18.560 you've you've probably heard stats like if you were to 0:16:18.600 --> 0:16:22.400 teleport to the top of Mount Everest, Uh, the difficulty 0:16:22.520 --> 0:16:25.040 you would you would have in getting enough air into 0:16:25.040 --> 0:16:27.360 your body to stay alive. Oh yeah, And this is 0:16:27.400 --> 0:16:29.320 this is something that's really interesting. I want to linger 0:16:29.360 --> 0:16:31.400 on this for a moment, because we've established that we've 0:16:31.400 --> 0:16:36.200 got this really powerful, fascinating force of atmospheric pressure always 0:16:36.240 --> 0:16:39.600 affecting us, but we don't normally notice it because we're 0:16:39.640 --> 0:16:43.080 we're acclimatized to it, we're in equilibrium with it um 0:16:43.160 --> 0:16:47.240 and we only normally notice its effects by its absence. 0:16:47.280 --> 0:16:50.240 When we're at low pressure, that's when when you start 0:16:50.280 --> 0:16:53.480 to notice what air pressure is. And of course, as 0:16:53.480 --> 0:16:55.680 you're saying, when you climb a mountain and reach a higher, 0:16:55.840 --> 0:16:59.920 high enough altitude, atmospheric pressure is lower. There's less atmosphere 0:17:00.000 --> 0:17:02.360 sussing down from above, so the air is less dense, 0:17:02.440 --> 0:17:05.440 meaning every time you take a breath, you literally get 0:17:05.560 --> 0:17:09.440 fewer oxygen molecules. They're just it's less dense. You're getting 0:17:09.520 --> 0:17:12.520 less with each pull. Yeah. This is also the very 0:17:12.560 --> 0:17:15.720 reason that in your airplane safety videos they stress that 0:17:15.720 --> 0:17:18.399 if the cabin loses pressure, because little masks are going 0:17:18.480 --> 0:17:20.040 to fall down and you need to put them on 0:17:20.240 --> 0:17:22.600 in order to keep breathing right or you will very 0:17:22.680 --> 0:17:26.399 quickly encounter hypoxia, you know, like lack of oxygen and 0:17:26.440 --> 0:17:29.080 the breaths you take, and that of course can lead 0:17:29.119 --> 0:17:30.800 to all kinds of bad stuff in the body. You 0:17:30.840 --> 0:17:34.399 need oxygen continuously immediately. And of course, so what this 0:17:34.520 --> 0:17:36.800 means when you get up to a high altitude, as 0:17:36.840 --> 0:17:38.960 it can lead to a heavy breathing in order to 0:17:39.000 --> 0:17:42.040 compensate for the lack of oxygen and each breath, uh 0:17:42.080 --> 0:17:45.840 and all kinds of stuff weakness, dizziness, potentially dehydration or 0:17:45.840 --> 0:17:49.679 even loss of consciousness. I've experienced high altitude environments. I 0:17:49.800 --> 0:17:52.119 assume you have at some point as well, and it's 0:17:52.119 --> 0:17:56.840 it's a kind of alarming feeling, you know, like you 0:17:56.880 --> 0:18:00.119 suddenly go up like ten ft worth of stairs and 0:18:00.240 --> 0:18:02.480 like normally that wouldn't be a problem, but you're start 0:18:02.520 --> 0:18:06.119 you're feeling lightheaded. And I remember encountering this on a 0:18:06.200 --> 0:18:09.600 trip to Arizona where we be We began in Phoenix 0:18:10.000 --> 0:18:12.840 and then we were heading up um, you know, rising 0:18:12.880 --> 0:18:16.640 in altitude as we were heading eventually towards the canyon, 0:18:17.160 --> 0:18:19.399 the Grand Canyon, UH. And I think we're somewhere in 0:18:19.400 --> 0:18:22.000 your Flagstaff where we stopped, got out and had his 0:18:22.080 --> 0:18:25.920 beautiful walk. The leaves were golden. But I also think 0:18:25.960 --> 0:18:28.600 we were like it was like we we that the 0:18:28.640 --> 0:18:31.760 altitude changed as such that we felt maybe like a 0:18:31.760 --> 0:18:34.359 little more exhausted by the walk and everything seemed like 0:18:34.359 --> 0:18:38.560 a little more magical in a weird way. Yeah. Yeah, 0:18:38.600 --> 0:18:41.960 I definitely experienced this sum when I was up up 0:18:41.960 --> 0:18:44.000 in Canada, when like we went on the hike to 0:18:44.119 --> 0:18:47.600 the Burgess Shale National Park area and uh to see 0:18:47.640 --> 0:18:49.720 the trilobyte beds up there, which if you haven't done, 0:18:49.760 --> 0:18:52.679 I highly recommend, but researched the hike before you do it. 0:18:53.160 --> 0:18:55.879 But also I've experienced this like in New Mexico and 0:18:55.920 --> 0:18:58.720 the mountains around Albuquerque and Santa Fe which can get 0:18:59.040 --> 0:19:02.159 really high elevation sition and you really start to feel it. 0:19:02.840 --> 0:19:05.560 Of course, altitude sickness can vary a lot in where 0:19:05.560 --> 0:19:08.520 it sets in. It's usually said that it begins somewhere 0:19:08.560 --> 0:19:12.000 around fifteen hundred to three thousand meters above sea level, 0:19:12.040 --> 0:19:15.320 but it varies a lot from person to person. And 0:19:15.520 --> 0:19:18.680 I kind of wonder about something. This got me thinking 0:19:18.720 --> 0:19:23.520 about the prevalence of beliefs about the sacred or religious 0:19:23.560 --> 0:19:28.199 significance of mountain tops. Like so, there are tons and 0:19:28.280 --> 0:19:32.120 tons of examples of sacred mountain tops or beliefs about 0:19:32.119 --> 0:19:35.280 the religious significance of mountain peaks around the world. There's, 0:19:35.320 --> 0:19:37.879 of course, you know, familiar one to us, mount Mount Olympus, 0:19:38.119 --> 0:19:40.800 the home to the gods in Greek mythology. But they're 0:19:40.800 --> 0:19:44.720 just literally hundreds of sacred and holy mountains around the 0:19:44.720 --> 0:19:47.520 world that are either homes of the gods or peaks 0:19:47.520 --> 0:19:50.800 of sacred pilgrimage, or places where people go to meditate, 0:19:51.119 --> 0:19:55.040 you know, near mountain peaks, mountain top monasteries considered sacred 0:19:55.080 --> 0:19:58.080 in some forms of Buddhism and all that. Um I 0:19:58.240 --> 0:20:02.040 was thinking about Mount Kailash or Kailassa into bed Ah. 0:20:02.080 --> 0:20:05.280 So you're saying mountaintops where the air is thin and 0:20:05.320 --> 0:20:08.480 the gods are near. Yeah, I wonder. Now I'm not sure, 0:20:08.520 --> 0:20:10.720 but there could be a lot of reasons for belief 0:20:10.760 --> 0:20:13.159 in the mountaintops being homes of the gods or sacred 0:20:13.200 --> 0:20:15.359 places in general. And I think there's one clearer piece 0:20:15.359 --> 0:20:18.639 of evidence that not all beliefs about sacred mountain tops 0:20:18.640 --> 0:20:20.840 have to do with altitude, because many of the holy 0:20:20.880 --> 0:20:22.960 mountains of the world aren't even that tall. I was 0:20:23.000 --> 0:20:25.320 thinking about there's one in Japan called, I think Mountain 0:20:25.320 --> 0:20:28.600 Mihwa that's like not even five So it's clearly not 0:20:28.680 --> 0:20:31.560 like an altitude sickness thing going on there. So there's 0:20:31.600 --> 0:20:34.280 obviously there are obviously other things contributing to these types 0:20:34.320 --> 0:20:38.159 of beliefs. But I wonder if one factor contributing to 0:20:38.280 --> 0:20:41.880 the widespread prevalence of belief in holy mountains is altitude sickness. 0:20:42.040 --> 0:20:44.800 As you climb toward the top of a very tall mountain, 0:20:45.040 --> 0:20:49.720 you're very likely to experience heavy breathing, weakness, dizziness, dehydration, 0:20:49.880 --> 0:20:52.800 loss of consciousness. And I can even imagine these like 0:20:53.000 --> 0:20:57.960 mundane types of physiological obstacles presenting too ancient mountain climbers 0:20:57.960 --> 0:21:01.439 a kind of invisible power of magic or repelling force 0:21:01.480 --> 0:21:04.720 that attempts to bar entry or repel you from the 0:21:04.720 --> 0:21:08.080 sacred domain of the gods. Interesting. Oh yeah, I like 0:21:08.119 --> 0:21:11.439 this hypothesis and actually does go farther than that. Like 0:21:11.520 --> 0:21:15.200 Apart from the mere hypoxic conditions caused by low air 0:21:15.200 --> 0:21:18.280 pressure at altitude, there are plenty of records of high altitudes, 0:21:18.400 --> 0:21:21.360