1 00:00:01,040 --> 00:00:04,520 Speaker 1: Welcome to Stuff you Should Know from House Stuff Works 2 00:00:04,519 --> 00:00:13,680 Speaker 1: dot com. Hey, and welcome to the podcast. I'm Josh Clark. 3 00:00:13,840 --> 00:00:17,200 Speaker 1: There's Charles W Chuck Bryant, and this is Stuff you 4 00:00:17,239 --> 00:00:21,680 Speaker 1: Should Know podcast. Yeah, what are you excited about this one? 5 00:00:23,280 --> 00:00:26,360 Speaker 1: I'm going to try to be excited for everybody enough 6 00:00:26,400 --> 00:00:29,159 Speaker 1: for everybody, because I imagine, like there's a you know, 7 00:00:29,200 --> 00:00:31,000 Speaker 1: there's a lot of people out there who don't listen 8 00:00:31,040 --> 00:00:34,479 Speaker 1: to every single episode. I just I find it biting 9 00:00:34,720 --> 00:00:37,760 Speaker 1: in weird because I do that with my podcast. So 10 00:00:37,920 --> 00:00:40,559 Speaker 1: if I'm like, if I'm listening to like if I 11 00:00:40,600 --> 00:00:42,239 Speaker 1: look at Mark Marrin', so I listen to that one. 12 00:00:42,240 --> 00:00:44,000 Speaker 1: If it's a guest that I'm not super into, I 13 00:00:44,000 --> 00:00:47,760 Speaker 1: want right, that's other podcasts. I'm talking about Stuff you 14 00:00:47,800 --> 00:00:50,760 Speaker 1: Should Know. Man, you must be confused. Yes, I feel 15 00:00:50,800 --> 00:00:52,720 Speaker 1: like every single one of them is worth listening to. 16 00:00:53,159 --> 00:00:55,720 Speaker 1: I agreed. I suspect though, that people are going to 17 00:00:55,760 --> 00:00:58,680 Speaker 1: skip over this one. Well, I am going to take 18 00:00:58,680 --> 00:01:01,160 Speaker 1: the rap because I picked this out. I like it, 19 00:01:01,320 --> 00:01:02,920 Speaker 1: but as I looked into it, I was like, you 20 00:01:02,960 --> 00:01:05,080 Speaker 1: know what, I don't know how an aerosol can work, 21 00:01:05,760 --> 00:01:09,720 Speaker 1: and I would like to and it's not super complicated. 22 00:01:09,760 --> 00:01:11,600 Speaker 1: It's not. In a matter of fact, now that you 23 00:01:12,080 --> 00:01:14,560 Speaker 1: read this and researched it, you understand how an aerosol 24 00:01:14,640 --> 00:01:17,040 Speaker 1: can works. You can go to the hardware store on 25 00:01:17,080 --> 00:01:19,240 Speaker 1: a Saturday when your board is just stand around and 26 00:01:19,280 --> 00:01:21,760 Speaker 1: explain it to people and get like applause. I could 27 00:01:21,800 --> 00:01:25,160 Speaker 1: do that. Every anyone who listens to this episode will 28 00:01:25,160 --> 00:01:26,760 Speaker 1: be able to do the same thing. That would be 29 00:01:26,880 --> 00:01:29,039 Speaker 1: like ACE Hardware, and there'll be some seventy five year 30 00:01:29,040 --> 00:01:31,000 Speaker 1: old guy with the red vest next to me. Like 31 00:01:31,080 --> 00:01:34,800 Speaker 1: all piste off, they always have old timer's working there. Well. 32 00:01:34,840 --> 00:01:39,160 Speaker 1: They are big on keeping the economy going on the 33 00:01:39,200 --> 00:01:44,679 Speaker 1: backs of aged baby boomers and that there's a slogan, Yeah, 34 00:01:44,880 --> 00:01:47,360 Speaker 1: I think it's ACE is the place. Well, you have 35 00:01:47,400 --> 00:01:50,680 Speaker 1: to read between the line, Um, chuck. Have you ever 36 00:01:50,720 --> 00:01:54,680 Speaker 1: seen a movie called Style Wars. It's a documentary from 37 00:01:56,000 --> 00:01:59,160 Speaker 1: Uh no, I haven't. It's pretty cool man. It's it 38 00:01:59,360 --> 00:02:06,040 Speaker 1: basically arnicles the the rise of graffiti, hip hop, clothing 39 00:02:06,040 --> 00:02:09,760 Speaker 1: and stuff, and break dancing, just that whole culture. And 40 00:02:09,880 --> 00:02:12,600 Speaker 1: it's amazing the stuff that people were doing, like even 41 00:02:12,639 --> 00:02:15,040 Speaker 1: back then as far as graffiti goes, and breakdancing and 42 00:02:15,160 --> 00:02:17,160 Speaker 1: hip hop and all that, sure, but it's just like 43 00:02:17,200 --> 00:02:19,639 Speaker 1: the seminal documentary that you just kind of have to see. 44 00:02:19,680 --> 00:02:22,919 Speaker 1: It's just so cool. It's like it kind of makes 45 00:02:22,960 --> 00:02:25,200 Speaker 1: you feel cool watching it, you know what I mean? Well, 46 00:02:25,240 --> 00:02:27,840 Speaker 1: I need that in my life. But the what the 47 00:02:27,880 --> 00:02:32,080 Speaker 1: reason I raised style Wars is because the graffiti that 48 00:02:32,200 --> 00:02:34,760 Speaker 1: was being carried out would not have ever been able 49 00:02:34,800 --> 00:02:38,359 Speaker 1: to be done had it not been for a Norwegian 50 00:02:38,360 --> 00:02:43,680 Speaker 1: engineer named Eric Rothheim who in put in the first 51 00:02:43,760 --> 00:02:47,359 Speaker 1: patent for an aerosol can in Norway and then five 52 00:02:47,440 --> 00:02:50,000 Speaker 1: years later the first one in the US. Yeah, and 53 00:02:50,040 --> 00:02:52,359 Speaker 1: they had the little photo of some of his initial drawings, 54 00:02:52,400 --> 00:02:55,600 Speaker 1: and the author of this article points out that although 55 00:02:56,160 --> 00:02:58,640 Speaker 1: it has evolved somewhat, it's he's He was pretty right 56 00:02:58,680 --> 00:03:01,839 Speaker 1: on with that first, is right, you know, almost out 57 00:03:01,840 --> 00:03:05,000 Speaker 1: of the gate, because as we said, it's kind of simple. 58 00:03:05,560 --> 00:03:07,440 Speaker 1: The Yeah, one of them was simple to me. One 59 00:03:07,440 --> 00:03:10,959 Speaker 1: of them I didn't quite understand. Well, okay, so um 60 00:03:11,000 --> 00:03:13,800 Speaker 1: so Rothheim he comes up with this, this patent files, 61 00:03:13,840 --> 00:03:16,840 Speaker 1: it kicks back and waits for the money to come 62 00:03:16,919 --> 00:03:20,320 Speaker 1: rolling in, but it doesn't. It took many many years 63 00:03:21,560 --> 00:03:25,200 Speaker 1: or so maybe a little less before anyone fully understood 64 00:03:25,560 --> 00:03:29,839 Speaker 1: the value of an aerosol can, and it was um insecticides, 65 00:03:29,960 --> 00:03:34,720 Speaker 1: bug bombs, cans of um insects spray that was being 66 00:03:34,840 --> 00:03:37,200 Speaker 1: used by soldiers in the Pacific and World War Two. 67 00:03:37,320 --> 00:03:42,160 Speaker 1: When people finally said, oh, that is a good idea. Yeah, 68 00:03:42,160 --> 00:03:44,600 Speaker 1: I wonder if I mean they had atomizers and things 69 00:03:44,640 --> 00:03:46,240 Speaker 1: at the time. I wonder if that was his initial 70 00:03:46,280 --> 00:03:50,880 Speaker 1: inspiration was to take that concept and jam it into 71 00:03:51,080 --> 00:03:56,040 Speaker 1: a can basically, because that's what's going on. Yeah, you're 72 00:03:56,080 --> 00:04:01,160 Speaker 1: atomizing product. Yeah, and there's a lot of um advantages 73 00:04:01,240 --> 00:04:03,840 Speaker 1: to atomizing. Number one, if you spray something in a 74 00:04:03,880 --> 00:04:06,480 Speaker 1: fine mist, it doesn't hit the ground. Is a bunch 75 00:04:06,480 --> 00:04:09,360 Speaker 1: of liquid that seeks into the groundwater usually sticks to 76 00:04:09,400 --> 00:04:13,320 Speaker 1: whatever you're spraying it to. Sure, and it's delightful if 77 00:04:13,400 --> 00:04:15,960 Speaker 1: you wear perfume or have you ever like had the 78 00:04:16,040 --> 00:04:18,760 Speaker 1: rose water sprayed on your face, like the face sprays. Oh, 79 00:04:18,800 --> 00:04:20,720 Speaker 1: I thought you meant like an aerosol can of perfect 80 00:04:20,760 --> 00:04:25,600 Speaker 1: no atomizing in general? Yeah, sure, sure, I'm fresh. I've 81 00:04:25,720 --> 00:04:29,039 Speaker 1: I've had an avian sprits sprayed on my face. You 82 00:04:29,080 --> 00:04:30,920 Speaker 1: mean I have before? It's very nice. Yeah, I've had 83 00:04:30,920 --> 00:04:33,719 Speaker 1: like the rosewater. Emily will spraying me occasionally. It's very nice. 84 00:04:34,040 --> 00:04:36,239 Speaker 1: It just feels good. Does she like hide behind around 85 00:04:36,279 --> 00:04:40,800 Speaker 1: a corner and yeah, no, that's the mace. Oh she 86 00:04:40,880 --> 00:04:46,400 Speaker 1: mazes me occasionally for kicks. Um. So yeah, there's advantages 87 00:04:46,440 --> 00:04:49,560 Speaker 1: to atomizing things. There's reasons. It's at the very least 88 00:04:49,600 --> 00:04:54,560 Speaker 1: it's lovely. It is um and the whole premise behind 89 00:04:54,680 --> 00:04:58,760 Speaker 1: this though, the delivery method of an aerosol can Like 90 00:04:58,800 --> 00:05:01,200 Speaker 1: we said, it's very basic, it's very old, and all 91 00:05:01,240 --> 00:05:03,599 Speaker 1: you have to do is understand a little bit about 92 00:05:03,760 --> 00:05:08,760 Speaker 1: fluid dynamics to to get what's going on. So let's 93 00:05:08,839 --> 00:05:11,360 Speaker 1: let's do let's give a brief prime around fluid dynamic 94 00:05:11,400 --> 00:05:14,960 Speaker 1: shall yeah, and fluid period Like you know, fluid isn't 95 00:05:14,960 --> 00:05:18,760 Speaker 1: necessarily liquid like you might think it's an actual thing. 96 00:05:18,800 --> 00:05:22,400 Speaker 1: Fluid is any kind of substance that has free flowing 97 00:05:22,440 --> 00:05:24,960 Speaker 1: particles that it's made up of that and it could 98 00:05:24,960 --> 00:05:27,880 Speaker 1: be something liquid, could be something gas that those are 99 00:05:27,920 --> 00:05:32,159 Speaker 1: both fluids. It just can't be a solid basically pretty much. Yeah, yeah, 100 00:05:32,160 --> 00:05:35,279 Speaker 1: as long as you got those free flowing particles. Um, 101 00:05:35,360 --> 00:05:38,440 Speaker 1: these particles, uh, if it's a liquid, they're loosely bound, 102 00:05:38,440 --> 00:05:40,680 Speaker 1: but they're still bound. So it means it's gonna have 103 00:05:40,680 --> 00:05:42,880 Speaker 1: a fixed volume if it's a liquid. Yeah, which is why, 104 00:05:42,960 --> 00:05:46,119 Speaker 1: like when you put water into a glass, it doesn't 105 00:05:46,160 --> 00:05:49,240 Speaker 1: just keep going and going and going. That'd be terrifying. No, 106 00:05:49,560 --> 00:05:53,039 Speaker 1: it would make it. It would have a gaseous um characteristic. 107 00:05:53,080 --> 00:05:55,919 Speaker 1: Then that's right, because gas does expand to fill the 108 00:05:56,000 --> 00:05:58,919 Speaker 1: volume that you put it in. That's right, and well, 109 00:05:59,320 --> 00:06:03,360 Speaker 1: spoiler or that's what happens with gas. It expands. Uh, 110 00:06:03,400 --> 00:06:07,360 Speaker 1: if you heat liquid um applying energy to it, basically 111 00:06:07,720 --> 00:06:11,800 Speaker 1: it's gonna vibrate and it's gonna break those forces and 112 00:06:11,920 --> 00:06:13,960 Speaker 1: they're not gonna be bound together anymore. Then you're gonna 113 00:06:13,960 --> 00:06:16,599 Speaker 1: have a gas. And that's called boiling. Yeah. And I 114 00:06:16,600 --> 00:06:19,480 Speaker 1: mean we think of boiling is like applying enough heat 115 00:06:19,520 --> 00:06:23,320 Speaker 1: that you will burn your skin. But boiling points vary 116 00:06:23,400 --> 00:06:27,159 Speaker 1: for different types of fluids. Um. So any volatile fluid 117 00:06:27,240 --> 00:06:30,279 Speaker 1: is a fluid that um boils or turns from a 118 00:06:30,320 --> 00:06:33,400 Speaker 1: liquid state to a gasy state. That's boiling um at 119 00:06:33,480 --> 00:06:36,719 Speaker 1: room temperature, right, Yeah, Which that that's the part I 120 00:06:36,760 --> 00:06:39,000 Speaker 1: had a hard time getting my head around because I 121 00:06:39,000 --> 00:06:42,040 Speaker 1: associate boiling with like heat and hot. Yeah. Because you 122 00:06:42,040 --> 00:06:44,600 Speaker 1: think of boiling, you think of water, Yeah, exactly. And 123 00:06:44,720 --> 00:06:48,159 Speaker 1: it takes a certain amount of temperature, of heat of 124 00:06:48,320 --> 00:06:52,400 Speaker 1: heat energy to break those intermolecular bonds to turn water 125 00:06:52,520 --> 00:06:55,359 Speaker 1: from a liquid into a gas, that's right. But it 126 00:06:55,400 --> 00:06:58,520 Speaker 1: takes less for alcohol or for propane or whatever you 127 00:06:58,600 --> 00:07:02,480 Speaker 1: want to use. Right. And so lastly there's another fluid 128 00:07:02,560 --> 00:07:04,600 Speaker 1: dynamic trait that we have to have down and then 129 00:07:04,640 --> 00:07:08,039 Speaker 1: we'll have all of the stuff in place to understand 130 00:07:08,080 --> 00:07:12,200 Speaker 1: an aerosol can expansion of gas. Yeah, So so we 131 00:07:12,240 --> 00:07:14,640 Speaker 1: said that when you put gas into something and expands 132 00:07:14,680 --> 00:07:18,840 Speaker 1: to fill the volume, Yeah, and gas will decrease in 133 00:07:18,880 --> 00:07:22,200 Speaker 1: pressure as it expands, which is why like a tiny 134 00:07:22,240 --> 00:07:25,280 Speaker 1: little CEO two cartridge, it's like got tons of pressure 135 00:07:25,320 --> 00:07:27,520 Speaker 1: in there, and that's why it can shoot your awesome 136 00:07:28,280 --> 00:07:32,760 Speaker 1: industrial arts model car down the track. Because did you 137 00:07:32,760 --> 00:07:36,760 Speaker 1: ever do that? Really? I had a Pinewood Derby racer once. 138 00:07:37,760 --> 00:07:40,280 Speaker 1: What's that like the car you sit in? No, that's 139 00:07:40,320 --> 00:07:43,200 Speaker 1: the cub scout car. Okay, it didn't have any CEO 140 00:07:43,240 --> 00:07:46,640 Speaker 1: two though you'd be immediately disqualified. Yeah. In high school, 141 00:07:46,640 --> 00:07:48,760 Speaker 1: we we made the little cars that have the CEO 142 00:07:48,800 --> 00:07:50,760 Speaker 1: two cartridge in the battle. I know what you're talking about. 143 00:07:50,800 --> 00:07:53,160 Speaker 1: And we raced each other and my brother one county 144 00:07:53,240 --> 00:07:56,480 Speaker 1: of course, and then and then flashed this winning smile, 145 00:07:56,720 --> 00:07:58,680 Speaker 1: and three years later, it's so funny. I forgot all 146 00:07:58,680 --> 00:08:01,160 Speaker 1: about this. I tried to be his car design when 147 00:08:01,200 --> 00:08:05,320 Speaker 1: I took the class, and mine was not nearly as like, 148 00:08:06,680 --> 00:08:09,679 Speaker 1: it just wasn't quite right, and I didn't win county. 149 00:08:09,720 --> 00:08:14,520 Speaker 1: I didn't even win my classroom. Somehow, the the compressed 150 00:08:14,600 --> 00:08:17,600 Speaker 1: air decompressing into the atmosphere made like a sad trombo 151 00:08:17,680 --> 00:08:20,000 Speaker 1: and sad is it so cool? And that really kind 152 00:08:20,000 --> 00:08:21,880 Speaker 1: of just sums it all up with my brother and I. 153 00:08:22,720 --> 00:08:24,559 Speaker 1: He was always really great at stuff, and I always 154 00:08:24,600 --> 00:08:27,040 Speaker 1: tried to do that and was not nearly as good 155 00:08:27,080 --> 00:08:29,960 Speaker 1: at it. You're good at other things. Well, I'm yeah, 156 00:08:30,160 --> 00:08:33,920 Speaker 1: I can run my mouth, if that's how you want 157 00:08:33,960 --> 00:08:37,320 Speaker 1: to put it. Anyway, So that's compressed gas. And when 158 00:08:37,360 --> 00:08:39,760 Speaker 1: gas is compressed, it can you know, do some great 159 00:08:39,760 --> 00:08:42,920 Speaker 1: things like shoot the car or in this case, spray 160 00:08:42,920 --> 00:08:47,000 Speaker 1: paint or something. Right, right, exactly, Okay, So you have 161 00:08:47,040 --> 00:08:49,560 Speaker 1: compressed gas, you have all these fluid dynamics, and you've 162 00:08:49,600 --> 00:08:53,319 Speaker 1: had everyone now right, Okay, So all an aerosol can 163 00:08:53,480 --> 00:08:56,040 Speaker 1: is is all of these principles kind of put into 164 00:08:56,040 --> 00:09:02,760 Speaker 1: a very simply mechanically functioning state. Right. Yeah. So you 165 00:09:02,800 --> 00:09:07,080 Speaker 1: have a can and you have to to things in there. 166 00:09:07,240 --> 00:09:10,800 Speaker 1: You have the propellant, which is the stuff you use 167 00:09:10,880 --> 00:09:14,640 Speaker 1: to force the other thing, the product out. Yeah. And 168 00:09:14,720 --> 00:09:19,360 Speaker 1: it could be hair spray, bug spray, could be painting oil, 169 00:09:19,520 --> 00:09:23,559 Speaker 1: could be that foamy stuff you ever use that, the 170 00:09:23,600 --> 00:09:26,520 Speaker 1: stuff to like seal like insulation or sure or like 171 00:09:26,600 --> 00:09:33,079 Speaker 1: fix the flat. All that, all that has myriad myriad uses. Okay, right, So, um, 172 00:09:33,160 --> 00:09:36,760 Speaker 1: you've got the product in liquid state. Yes, uh say, 173 00:09:36,760 --> 00:09:38,559 Speaker 1: it's just kind of floating in the bottom of the can. 174 00:09:39,240 --> 00:09:43,120 Speaker 1: You put it in the can, seal it so it's 175 00:09:43,160 --> 00:09:45,760 Speaker 1: there's there's no air going it's air tight. Yeah, this 176 00:09:45,800 --> 00:09:47,559 Speaker 1: is part one. There's two two ways to do this. 177 00:09:47,559 --> 00:09:49,440 Speaker 1: This is the first, right, This is the simple way. 178 00:09:49,800 --> 00:09:53,720 Speaker 1: And then you add some sort of compressed air to it, 179 00:09:53,960 --> 00:09:57,880 Speaker 1: call it air compressed air. Okay, okay. So you have 180 00:09:58,000 --> 00:10:02,200 Speaker 1: this um the propellant in there, and it's it's basically 181 00:10:02,280 --> 00:10:04,640 Speaker 1: filling up as much of it as it can until 182 00:10:04,679 --> 00:10:06,599 Speaker 1: it's reaching the top of the can, the side of 183 00:10:06,600 --> 00:10:08,240 Speaker 1: the can, in the top of the water, and it 184 00:10:08,280 --> 00:10:10,720 Speaker 1: pushes all that product down to the bottom, which is 185 00:10:10,720 --> 00:10:12,720 Speaker 1: one reason you gotta shake it chack it up exactly. 186 00:10:13,240 --> 00:10:16,600 Speaker 1: So you have a tube going down from the nozzle 187 00:10:16,960 --> 00:10:19,640 Speaker 1: at the top of the can valve system all the 188 00:10:19,640 --> 00:10:22,240 Speaker 1: way down to the bottom of the can where the 189 00:10:22,280 --> 00:10:25,560 Speaker 1: liquid is right and that look, that valve has a 190 00:10:25,640 --> 00:10:29,319 Speaker 1: seal that's being pushed up by a spring. So the 191 00:10:29,360 --> 00:10:32,559 Speaker 1: head the nozzle when it's when it's not being pushed, 192 00:10:32,920 --> 00:10:35,840 Speaker 1: it's stealed tight. But when you push it down a 193 00:10:35,960 --> 00:10:40,320 Speaker 1: channel opens. It goes below the seal and you now 194 00:10:40,440 --> 00:10:43,559 Speaker 1: have the outside atmosphere, which is at a much lower 195 00:10:43,559 --> 00:10:47,400 Speaker 1: pressure than inside the can um opened up to the 196 00:10:47,440 --> 00:10:50,000 Speaker 1: inside of the can at that much higher pressure, and 197 00:10:50,080 --> 00:10:53,120 Speaker 1: it drives it up the tube out the little tiny, 198 00:10:53,160 --> 00:10:57,439 Speaker 1: tiny hole which atomizes it. And that's basically the simpler 199 00:10:58,040 --> 00:11:00,560 Speaker 1: method of the aerosol can. Yeah. The air pushes the 200 00:11:00,559 --> 00:11:02,839 Speaker 1: liquid down and then up the tube. Yeah, because it's 201 00:11:02,880 --> 00:11:06,920 Speaker 1: like I want to get out too exactly. It expands. Done. 202 00:11:07,000 --> 00:11:10,320 Speaker 1: I mean that's pretty easy. Yeah. So the second way 203 00:11:10,400 --> 00:11:12,040 Speaker 1: that this can happen, and I didn't know this is 204 00:11:12,040 --> 00:11:14,640 Speaker 1: the more common way, but it is. Uh they use 205 00:11:14,720 --> 00:11:19,559 Speaker 1: liquified gas, so uh, that is the propellant. You've still 206 00:11:19,600 --> 00:11:23,440 Speaker 1: got the same product. And the product is is sitting 207 00:11:23,480 --> 00:11:25,640 Speaker 1: there at room temperature just fine as a liquid. So 208 00:11:25,679 --> 00:11:28,079 Speaker 1: they just pour that in. Then they steal it up, 209 00:11:28,120 --> 00:11:30,240 Speaker 1: and then the same way with the other way. They 210 00:11:30,280 --> 00:11:35,280 Speaker 1: pump in this liquefied gas and it mixes though this time, 211 00:11:35,400 --> 00:11:37,480 Speaker 1: right or does it press it down? This is where 212 00:11:37,480 --> 00:11:39,920 Speaker 1: I got a little confused. So a liquefied guess you said, 213 00:11:40,000 --> 00:11:43,160 Speaker 1: is um, it's a gas that goes into a liquid 214 00:11:43,160 --> 00:11:45,280 Speaker 1: state under a certain amount of pressure, right, yeah, okay, 215 00:11:45,400 --> 00:11:49,199 Speaker 1: so under high pressure. Yeah, so it does mix because 216 00:11:49,200 --> 00:11:51,120 Speaker 1: it's all liquid in there. Once it gets in there, 217 00:11:51,559 --> 00:11:53,800 Speaker 1: the whole thing turns liquid, and you keep that pressure 218 00:11:53,880 --> 00:11:55,800 Speaker 1: up so it doesn't have any room to expand, so 219 00:11:55,840 --> 00:11:59,000 Speaker 1: it's just in their mix together. And then when you 220 00:11:59,040 --> 00:12:01,240 Speaker 1: press the nozzle down own and you break the seal 221 00:12:01,280 --> 00:12:05,400 Speaker 1: as it were, um, the you form a channel with 222 00:12:05,440 --> 00:12:07,199 Speaker 1: the outside air and the inside air. That change in 223 00:12:07,240 --> 00:12:11,680 Speaker 1: pressure converts some of that propellant into gas, and it 224 00:12:11,760 --> 00:12:14,240 Speaker 1: does the same thing is that standard can. The gas 225 00:12:14,320 --> 00:12:18,520 Speaker 1: presses down forces the liquid up, but some of that 226 00:12:18,600 --> 00:12:21,520 Speaker 1: propellant is still in liquid form mixed with the product, 227 00:12:21,760 --> 00:12:26,200 Speaker 1: and as it goes out, it evaporates, it turns into gas, 228 00:12:26,520 --> 00:12:30,040 Speaker 1: and it also kind of um, it turns that liquid 229 00:12:30,120 --> 00:12:32,960 Speaker 1: product into a finer miss. Yeah. But what I don't 230 00:12:32,960 --> 00:12:35,320 Speaker 1: get is is that it actually boils in the liquid 231 00:12:35,320 --> 00:12:39,280 Speaker 1: gas system. It's like, once you relieve that pressure, it 232 00:12:39,400 --> 00:12:41,840 Speaker 1: starts to boil, and that's what does it. That's what 233 00:12:41,920 --> 00:12:43,600 Speaker 1: I was a little confused about. Yeah, I have a 234 00:12:43,640 --> 00:12:47,760 Speaker 1: feeling that this is a different part of fluid dynamics, 235 00:12:48,400 --> 00:12:51,760 Speaker 1: that it's not necessarily the boiling point, although it could be, 236 00:12:51,760 --> 00:12:54,640 Speaker 1: because I don't think any average gas turns into a 237 00:12:54,679 --> 00:12:58,960 Speaker 1: liquid under under all under pressure. There's just certain kinds 238 00:12:59,000 --> 00:13:04,439 Speaker 1: that do. I think. Okay, so I think, what's your question, Well, 239 00:13:04,440 --> 00:13:06,560 Speaker 1: it's actually boiling in the second in the in the 240 00:13:06,600 --> 00:13:09,079 Speaker 1: liquid gas type of aerosoli, at the very least, it's 241 00:13:09,120 --> 00:13:13,480 Speaker 1: converting into a gassy estate because of the release of pressure, right, 242 00:13:13,520 --> 00:13:15,400 Speaker 1: all right? And why did they can sometimes get cold? 243 00:13:15,440 --> 00:13:18,760 Speaker 1: Did you figure that out? Okay? Boy, there's some guts. 244 00:13:18,800 --> 00:13:21,160 Speaker 1: There's some people in chemistry lab right now that are 245 00:13:21,200 --> 00:13:25,040 Speaker 1: just like, oh my god, you guys, I thought we 246 00:13:25,080 --> 00:13:27,320 Speaker 1: had this one, man. I think we had we do 247 00:13:27,440 --> 00:13:28,880 Speaker 1: I had it, and I could have done a tap 248 00:13:28,960 --> 00:13:31,200 Speaker 1: dance doing this earlier, and now it's like, but wait, 249 00:13:31,280 --> 00:13:33,439 Speaker 1: let me complicate it a little more. Now, I think 250 00:13:33,480 --> 00:13:36,280 Speaker 1: it's I think the message got through. Um. If in 251 00:13:36,280 --> 00:13:38,680 Speaker 1: the case of paint, sometimes you need a little help 252 00:13:39,280 --> 00:13:41,840 Speaker 1: mixing these things together. So that's why a paint can, 253 00:13:42,080 --> 00:13:45,000 Speaker 1: spray paint can will have the little metal ball bearing 254 00:13:45,120 --> 00:13:47,680 Speaker 1: on the inside, right, because you actually do want to 255 00:13:47,720 --> 00:13:52,360 Speaker 1: mix the propellant and the product together in a liquefied can, 256 00:13:52,440 --> 00:13:57,079 Speaker 1: liquefied gas can, right, because it helps atomize it. As 257 00:13:57,120 --> 00:14:02,160 Speaker 1: you said, that's very pleasant, exact. Um, what about the 258 00:14:02,240 --> 00:14:04,960 Speaker 1: rounded bottom of this very can you know why that's 259 00:14:05,040 --> 00:14:08,720 Speaker 1: that way? If it was flat, it's so pressurized, it 260 00:14:08,840 --> 00:14:11,040 Speaker 1: could be a bad scene. It could actually go the 261 00:14:11,040 --> 00:14:15,160 Speaker 1: other way. And everyone knows if you studied architecture, that 262 00:14:15,240 --> 00:14:19,560 Speaker 1: a dome is more structurally sound than just a flat surface. 263 00:14:19,600 --> 00:14:22,360 Speaker 1: So that's basically the same concept at play. So that's 264 00:14:22,360 --> 00:14:26,480 Speaker 1: one reason, Um, it's to protect the integrity of the can. 265 00:14:26,960 --> 00:14:29,320 Speaker 1: And the second one is is so you can help 266 00:14:29,360 --> 00:14:32,200 Speaker 1: get all of the product out, because if it was flat, 267 00:14:32,280 --> 00:14:34,440 Speaker 1: it's like when you're down at the bottom of your 268 00:14:34,960 --> 00:14:37,600 Speaker 1: of your soda cup with your straw and you're making 269 00:14:37,600 --> 00:14:40,280 Speaker 1: that terrible little noise and you're tilting the cup and 270 00:14:40,320 --> 00:14:42,320 Speaker 1: trying to stick the straw on the little corner where 271 00:14:42,320 --> 00:14:44,400 Speaker 1: it meets the edge. This does it for you. If 272 00:14:44,400 --> 00:14:46,880 Speaker 1: it's a rounded bottom, it just puts all the product 273 00:14:46,920 --> 00:14:49,160 Speaker 1: there at the edge and that's where the little tube is, 274 00:14:49,400 --> 00:14:51,920 Speaker 1: and so you're all set. Yeah, And did you know 275 00:14:52,000 --> 00:14:55,640 Speaker 1: there's about nineteen billion steel and aluminum cans that include 276 00:14:55,640 --> 00:14:58,600 Speaker 1: aerosols and other products that are recycled every year and 277 00:14:58,640 --> 00:15:04,400 Speaker 1: that's equal to enough to build twenty golden gate bridges. Wow, 278 00:15:04,720 --> 00:15:07,960 Speaker 1: isn't that amazing? So we mentioned there's a variety of 279 00:15:07,960 --> 00:15:10,360 Speaker 1: different products that you can have that you're trying to 280 00:15:11,440 --> 00:15:13,880 Speaker 1: get out of your can, from foam to like whipped 281 00:15:13,880 --> 00:15:17,360 Speaker 1: cream to a bug spray, stuff like that hair spray, 282 00:15:17,400 --> 00:15:20,920 Speaker 1: although does anyone still use aerosol hair spray? I think 283 00:15:20,960 --> 00:15:24,400 Speaker 1: some people do, is it? Remember? Do you remember the 284 00:15:24,440 --> 00:15:29,680 Speaker 1: Bizarre Ways to Die episode? The deodorant boy asol deodorant 285 00:15:29,680 --> 00:15:33,480 Speaker 1: that he died totally man, that was a long time ago. Um. 286 00:15:33,520 --> 00:15:35,720 Speaker 1: So the way they accomplished this though with a different product, 287 00:15:35,920 --> 00:15:39,000 Speaker 1: um is you can have a variety of consistencies. And 288 00:15:39,040 --> 00:15:42,600 Speaker 1: what they do is they just play with, UM, the 289 00:15:42,720 --> 00:15:46,200 Speaker 1: ratio propellant to product. Maybe maybe the chemical makeup of 290 00:15:46,200 --> 00:15:48,760 Speaker 1: the propellant the product have to be just right. Maybe 291 00:15:48,800 --> 00:15:50,520 Speaker 1: the pressure of the propellant has to be a little 292 00:15:50,520 --> 00:15:52,840 Speaker 1: different depending on what kind of product you're working with. 293 00:15:53,320 --> 00:15:57,440 Speaker 1: And then um, the size and shape of the valve system. 294 00:15:57,480 --> 00:15:59,320 Speaker 1: Like in the case of a fix, the flat that 295 00:15:59,360 --> 00:16:01,840 Speaker 1: you put in your higher it's not the same as 296 00:16:01,920 --> 00:16:04,480 Speaker 1: you know, a spray can. It's not atomizing. It's got 297 00:16:04,480 --> 00:16:07,800 Speaker 1: like the tube hooked up and it's Uh. If you've 298 00:16:07,800 --> 00:16:09,960 Speaker 1: ever sprayed that stuff in your house, like the Philip Crack, 299 00:16:10,520 --> 00:16:12,560 Speaker 1: like a whole can of it, It's amazing how much 300 00:16:12,560 --> 00:16:15,240 Speaker 1: stuff is packed in there. Like when it gets out, 301 00:16:15,240 --> 00:16:17,240 Speaker 1: you're just like wow, it's like the clown car of 302 00:16:17,280 --> 00:16:22,680 Speaker 1: the industrial engineering scene. Um, do you want to know 303 00:16:22,720 --> 00:16:25,720 Speaker 1: a little bit about CFC's chlorofluora carbons. Yeah, I didn't 304 00:16:25,720 --> 00:16:27,160 Speaker 1: get a chance to look into this, but I'm glad 305 00:16:27,160 --> 00:16:31,600 Speaker 1: you did so. Prior to the late twenties, there was 306 00:16:31,960 --> 00:16:36,240 Speaker 1: people were using ammonia and refrigerators and dying from ammonia leaks, 307 00:16:36,280 --> 00:16:39,480 Speaker 1: and it was just a bad scene. And so everybody said, well, 308 00:16:39,560 --> 00:16:41,840 Speaker 1: we've got to figure out some sort of toxic, non 309 00:16:41,920 --> 00:16:45,360 Speaker 1: toxic chemical that we can use as a refrigerant, and 310 00:16:45,440 --> 00:16:48,480 Speaker 1: a general motors engineer of all people came up with 311 00:16:48,800 --> 00:16:53,000 Speaker 1: what du Pont later turned into free on, a chlorofluora 312 00:16:53,040 --> 00:16:56,840 Speaker 1: carbon which supposedly was non toxic. It was. It basically 313 00:16:56,920 --> 00:17:01,880 Speaker 1: changed everything. Um it was much less harm harmful compared 314 00:17:01,920 --> 00:17:06,000 Speaker 1: to like ammonia. UM. It allowed us to make cheap refrigerators, 315 00:17:06,800 --> 00:17:10,280 Speaker 1: car A C, A C window units, like all those 316 00:17:10,280 --> 00:17:13,760 Speaker 1: things came from the advent of chlorofluora carbons, right, And 317 00:17:14,080 --> 00:17:17,720 Speaker 1: it was also very ubiquitous as a propellant in aerosol 318 00:17:17,800 --> 00:17:21,800 Speaker 1: can sprays. Well. I think that's why everyone, you know 319 00:17:21,960 --> 00:17:25,840 Speaker 1: quit using aquinette, right, because everybody was going in the 320 00:17:25,920 --> 00:17:28,080 Speaker 1: spraying these things, and they were going up in the atmosphere, 321 00:17:28,119 --> 00:17:29,720 Speaker 1: and everyone was like, look at them. Go it's cool. 322 00:17:29,800 --> 00:17:34,040 Speaker 1: They're like, you know, innert, non toxic chemicals going up 323 00:17:34,040 --> 00:17:36,760 Speaker 1: in the atmosphere, but we're all getting cancer. The problem 324 00:17:36,920 --> 00:17:40,840 Speaker 1: is when a CFC enters the atmosphere and gets high 325 00:17:40,920 --> 00:17:44,439 Speaker 1: enough and it's exposed to UV radiation, it breaks down 326 00:17:44,680 --> 00:17:47,840 Speaker 1: and into its constituting components, one of which is chlorine, 327 00:17:48,280 --> 00:17:52,359 Speaker 1: chlorine reeks, havoc on the ozone layer. One atom of 328 00:17:52,440 --> 00:17:56,359 Speaker 1: chlorine can destroy about a hundred thousand ozone molecules, and 329 00:17:56,400 --> 00:17:59,000 Speaker 1: we need those molecules. The ozone layer protects us from 330 00:17:59,240 --> 00:18:01,399 Speaker 1: UVB ray from the sun, which are they kind of 331 00:18:01,520 --> 00:18:04,480 Speaker 1: give you skin cancer and destroyed crops. So in nineteen 332 00:18:04,560 --> 00:18:07,760 Speaker 1: seventy four some scientists realized that CFCs were doing this 333 00:18:07,880 --> 00:18:09,800 Speaker 1: in the ozone layer and is gonna be big trouble. 334 00:18:11,080 --> 00:18:13,440 Speaker 1: And then in the eighties we figured out that there's 335 00:18:13,440 --> 00:18:17,080 Speaker 1: a hole in the ozone layer over the Arctic. So, uh, 336 00:18:17,280 --> 00:18:20,720 Speaker 1: a bunch of countries I think seventies signed on to 337 00:18:21,359 --> 00:18:26,119 Speaker 1: basically outlaw CFC production. Yeah, and then later on another 338 00:18:26,400 --> 00:18:30,560 Speaker 1: like hundred and twenty I think signed another treaty. So 339 00:18:30,960 --> 00:18:34,600 Speaker 1: it's very very difficult to find CFC's these days. But 340 00:18:34,680 --> 00:18:37,200 Speaker 1: they're still around, are they. Yeah? They still use them 341 00:18:37,200 --> 00:18:41,800 Speaker 1: in some um nasal sprays UM and they're also used 342 00:18:41,880 --> 00:18:47,720 Speaker 1: in halan, which is a fire extinguisher for airplanes. Did 343 00:18:47,720 --> 00:18:51,680 Speaker 1: they not still use free on? No? I don't believe. So, Okay, Yeah, 344 00:18:51,680 --> 00:18:53,880 Speaker 1: it's basically like we did away with those. It's gonna 345 00:18:53,880 --> 00:18:55,480 Speaker 1: take a while to repair. But they found that the 346 00:18:55,480 --> 00:18:57,920 Speaker 1: ozone layers no longer growing the hole in the ozon 347 00:18:58,000 --> 00:19:02,399 Speaker 1: layers growing, it's just holding steady and hopefully patching itself 348 00:19:02,440 --> 00:19:04,320 Speaker 1: back up. They just forced people to go out and 349 00:19:04,320 --> 00:19:07,080 Speaker 1: be innovative and find different ways to do these things exactly. 350 00:19:07,119 --> 00:19:11,240 Speaker 1: And if you compare your airsol can propellant today to 351 00:19:11,440 --> 00:19:13,920 Speaker 1: one that had CFCs before, you're not going to notice 352 00:19:13,960 --> 00:19:17,120 Speaker 1: the least bit different. So that's canna aquinit that looks 353 00:19:17,160 --> 00:19:20,439 Speaker 1: exactly the same as it did in nineteen seven is 354 00:19:20,520 --> 00:19:24,480 Speaker 1: no longer dangerous, not to the ozone layer. It is 355 00:19:24,520 --> 00:19:28,480 Speaker 1: the spiders though, if you have a lighter. Yeah, don't 356 00:19:28,480 --> 00:19:31,920 Speaker 1: ever do that. Kids. Ah, that's it for airsol cans 357 00:19:32,000 --> 00:19:35,000 Speaker 1: unless you have like another ten minutes on it. Uh No, 358 00:19:35,200 --> 00:19:36,879 Speaker 1: that's all I got. I mean, what else is there? 359 00:19:37,520 --> 00:19:41,000 Speaker 1: I genuinely looked in There is nothing else. Ye, go 360 00:19:41,040 --> 00:19:43,840 Speaker 1: out and do some graffiti, That's what I say. Um 361 00:19:44,840 --> 00:19:47,600 Speaker 1: artful graffiti though, don't tagg and stuff. You should probably 362 00:19:47,640 --> 00:19:50,480 Speaker 1: practice at home first. I hate that. Just stupid. Yeah, Like, 363 00:19:51,920 --> 00:19:55,280 Speaker 1: educate yourself on different types of nozzles, like practice, don't 364 00:19:55,280 --> 00:19:59,359 Speaker 1: do don't be a punk, agreed, be an artiste. Uh. 365 00:19:59,400 --> 00:20:01,920 Speaker 1: If you we want to learn more about aerosols, or 366 00:20:01,920 --> 00:20:03,600 Speaker 1: at the very least, want to see the article where 367 00:20:03,600 --> 00:20:05,760 Speaker 1: we told you everything there is to know about aerosolis. 368 00:20:05,760 --> 00:20:08,040 Speaker 1: You can type that word A E R O S 369 00:20:08,080 --> 00:20:10,840 Speaker 1: O L S into the search bar how stuffworks dot 370 00:20:10,840 --> 00:20:13,160 Speaker 1: com and that will bring it up. And I said 371 00:20:13,160 --> 00:20:18,880 Speaker 1: the search bar, which means it's time for message break 372 00:20:23,240 --> 00:20:25,520 Speaker 1: and now it's time for listener mail. I thought you 373 00:20:25,600 --> 00:20:30,440 Speaker 1: might say it, okay, Josh, listener mail time. UM, I'm 374 00:20:30,440 --> 00:20:35,879 Speaker 1: gonna call this uh police sketch eye witnessed stuff. It's 375 00:20:35,920 --> 00:20:39,119 Speaker 1: from Terry Bennett. Um, Hey, guys, uh listen to the 376 00:20:39,119 --> 00:20:41,600 Speaker 1: police Sketch episode, and wanted to share my story. I 377 00:20:41,720 --> 00:20:43,320 Speaker 1: was robbed when I was a teller of a bank 378 00:20:43,640 --> 00:20:46,919 Speaker 1: in n and at that time, bank robbery was a 379 00:20:46,920 --> 00:20:50,200 Speaker 1: federal crime, probably still is. I was immediately taken into 380 00:20:50,280 --> 00:20:53,280 Speaker 1: the back room of the vault and the FBI was 381 00:20:53,359 --> 00:20:55,760 Speaker 1: called in. When they arrived, a sketch artist brought a 382 00:20:55,840 --> 00:20:59,440 Speaker 1: large binder, not full of women, but full of pictures. 383 00:20:59,800 --> 00:21:03,439 Speaker 1: They aces and eyes and noses and mouths, et cetera. 384 00:21:04,240 --> 00:21:07,960 Speaker 1: Transparencies of face shapes were the base, and the rest 385 00:21:07,960 --> 00:21:10,400 Speaker 1: of the face was built on the base, one eye 386 00:21:10,400 --> 00:21:12,919 Speaker 1: and nose at a time. UM I was not allowed 387 00:21:12,920 --> 00:21:15,040 Speaker 1: to talk to anyone, including the staff of my bank, 388 00:21:15,119 --> 00:21:17,800 Speaker 1: until I talked to the FBI. I was instructed to 389 00:21:17,800 --> 00:21:19,800 Speaker 1: write everything I could remember about the robber and the 390 00:21:19,840 --> 00:21:23,400 Speaker 1: robbery before talking to anybody else. In those days, of course, 391 00:21:23,440 --> 00:21:25,239 Speaker 1: we did not have digital cameras in the film had 392 00:21:25,240 --> 00:21:28,600 Speaker 1: to be sent out for processing. Um, all of it 393 00:21:28,800 --> 00:21:31,920 Speaker 1: in those days. I mean, it's the same like seven 394 00:21:32,160 --> 00:21:37,000 Speaker 1: years ago. Um. Actually when did digital come around? The 395 00:21:37,040 --> 00:21:39,840 Speaker 1: early two thousands? Seems like it became. I guess it's 396 00:21:39,840 --> 00:21:45,760 Speaker 1: more than seven three years on. So uh. The pictures 397 00:21:45,760 --> 00:21:47,240 Speaker 1: took a couple of days to get back, and my 398 00:21:47,320 --> 00:21:50,399 Speaker 1: composite drawing was posted in the paper, and my robber 399 00:21:50,480 --> 00:21:53,040 Speaker 1: was actually caught a couple of days afterward at a 400 00:21:53,119 --> 00:21:56,320 Speaker 1: methodon clinic in town. When the film was developed, the 401 00:21:56,440 --> 00:21:59,760 Speaker 1: side by side pictures were incredibly closed. So she did 402 00:21:59,840 --> 00:22:02,280 Speaker 1: for good job. Sounds like, by the way he was 403 00:22:02,320 --> 00:22:07,000 Speaker 1: caught using my composite and not the true picture. We're 404 00:22:07,040 --> 00:22:08,960 Speaker 1: pretty cool. Yeah, it's very cool. We were trained to 405 00:22:09,000 --> 00:22:12,280 Speaker 1: observe all these details and also to watch for the 406 00:22:12,320 --> 00:22:14,560 Speaker 1: six ft mark as the robber left the building. And 407 00:22:14,680 --> 00:22:17,399 Speaker 1: you talked about the call it stores. Yeah, Um, I 408 00:22:17,440 --> 00:22:19,920 Speaker 1: guess I visit banks. Luckily, even though I was only 409 00:22:19,960 --> 00:22:23,160 Speaker 1: twenty years old, the training had taken a hold gave 410 00:22:23,200 --> 00:22:25,800 Speaker 1: me great resources to catch this guy. And to this day, 411 00:22:25,920 --> 00:22:29,320 Speaker 1: I always observed shady or odd things in everyday life, 412 00:22:29,560 --> 00:22:32,240 Speaker 1: including license plates like you talked about. By the way, 413 00:22:32,400 --> 00:22:34,680 Speaker 1: my robber had robbed eight other banks up and down 414 00:22:34,680 --> 00:22:36,399 Speaker 1: the coast in California. And I got to be a 415 00:22:36,440 --> 00:22:39,399 Speaker 1: hero for a minute. And that is Terry Bennett. And 416 00:22:39,480 --> 00:22:43,119 Speaker 1: that's a cool story. Yeah, that's very cool, Terry. Um, 417 00:22:43,160 --> 00:22:46,400 Speaker 1: thanks for Sharon. I bet she just eyeballs everybody, right, Yeah, 418 00:22:46,480 --> 00:22:48,760 Speaker 1: she said that like a weird lady. Now she takes 419 00:22:48,760 --> 00:22:52,160 Speaker 1: out methodon clinics. Yeah, what are you doing? Just getting 420 00:22:52,160 --> 00:22:55,479 Speaker 1: the methodone. If you want to give us a story, 421 00:22:55,520 --> 00:22:58,919 Speaker 1: we love our stories. Um, you can tweet very very 422 00:22:59,040 --> 00:23:02,440 Speaker 1: very short story to us at s y s K podcast. 423 00:23:02,520 --> 00:23:05,600 Speaker 1: That's our Twitter handle. You can post one on Facebook 424 00:23:05,600 --> 00:23:07,800 Speaker 1: dot com slash Stuff you Should Know. You can send 425 00:23:07,840 --> 00:23:11,280 Speaker 1: in an email to Stuff Podcast at Discovery dot com 426 00:23:11,280 --> 00:23:13,399 Speaker 1: and you can't really tell us a story, but you 427 00:23:13,440 --> 00:23:16,000 Speaker 1: can hang out with us at our home on the web. 428 00:23:16,400 --> 00:23:23,960 Speaker 1: Stuff you should Know dot com for more on this 429 00:23:24,119 --> 00:23:26,600 Speaker 1: and thousands of other topics. Is it how stuff works 430 00:23:26,640 --> 00:23:35,879 Speaker 1: dot com. 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