WEBVTT - How Aerosol Cans Work 0:00:01.040 --> 0:00:04.520 Welcome to Stuff you Should Know from House Stuff Works 0:00:04.519 --> 0:00:13.680 dot com. Hey, and welcome to the podcast. I'm Josh Clark. 0:00:13.840 --> 0:00:17.200 There's Charles W Chuck Bryant, and this is Stuff you 0:00:17.239 --> 0:00:21.680 Should Know podcast. Yeah, what are you excited about this one? 0:00:23.280 --> 0:00:26.360 I'm going to try to be excited for everybody enough 0:00:26.400 --> 0:00:29.159 for everybody, because I imagine, like there's a you know, 0:00:29.200 --> 0:00:31.000 there's a lot of people out there who don't listen 0:00:31.040 --> 0:00:34.479 to every single episode. I just I find it biting 0:00:34.720 --> 0:00:37.760 in weird because I do that with my podcast. So 0:00:37.920 --> 0:00:40.559 if I'm like, if I'm listening to like if I 0:00:40.600 --> 0:00:42.239 look at Mark Marrin', so I listen to that one. 0:00:42.240 --> 0:00:44.000 If it's a guest that I'm not super into, I 0:00:44.000 --> 0:00:47.760 want right, that's other podcasts. I'm talking about Stuff you 0:00:47.800 --> 0:00:50.760 Should Know. Man, you must be confused. Yes, I feel 0:00:50.800 --> 0:00:52.720 like every single one of them is worth listening to. 0:00:53.159 --> 0:00:55.720 I agreed. I suspect though, that people are going to 0:00:55.760 --> 0:00:58.680 skip over this one. Well, I am going to take 0:00:58.680 --> 0:01:01.160 the rap because I picked this out. I like it, 0:01:01.320 --> 0:01:02.920 but as I looked into it, I was like, you 0:01:02.960 --> 0:01:05.080 know what, I don't know how an aerosol can work, 0:01:05.760 --> 0:01:09.720 and I would like to and it's not super complicated. 0:01:09.760 --> 0:01:11.600 It's not. In a matter of fact, now that you 0:01:12.080 --> 0:01:14.560 read this and researched it, you understand how an aerosol 0:01:14.640 --> 0:01:17.040 can works. You can go to the hardware store on 0:01:17.080 --> 0:01:19.240 a Saturday when your board is just stand around and 0:01:19.280 --> 0:01:21.760 explain it to people and get like applause. I could 0:01:21.800 --> 0:01:25.160 do that. Every anyone who listens to this episode will 0:01:25.160 --> 0:01:26.760 be able to do the same thing. That would be 0:01:26.880 --> 0:01:29.039 like ACE Hardware, and there'll be some seventy five year 0:01:29.040 --> 0:01:31.000 old guy with the red vest next to me. Like 0:01:31.080 --> 0:01:34.800 all piste off, they always have old timer's working there. Well. 0:01:34.840 --> 0:01:39.160 They are big on keeping the economy going on the 0:01:39.200 --> 0:01:44.679 backs of aged baby boomers and that there's a slogan, Yeah, 0:01:44.880 --> 0:01:47.360 I think it's ACE is the place. Well, you have 0:01:47.400 --> 0:01:50.680 to read between the line, Um, chuck. Have you ever 0:01:50.720 --> 0:01:54.680 seen a movie called Style Wars. It's a documentary from 0:01:56.000 --> 0:01:59.160 Uh no, I haven't. It's pretty cool man. It's it 0:01:59.360 --> 0:02:06.040 basically arnicles the the rise of graffiti, hip hop, clothing 0:02:06.040 --> 0:02:09.760 and stuff, and break dancing, just that whole culture. And 0:02:09.880 --> 0:02:12.600 it's amazing the stuff that people were doing, like even 0:02:12.639 --> 0:02:15.040 back then as far as graffiti goes, and breakdancing and 0:02:15.160 --> 0:02:17.160 hip hop and all that, sure, but it's just like 0:02:17.200 --> 0:02:19.639 the seminal documentary that you just kind of have to see. 0:02:19.680 --> 0:02:22.919 It's just so cool. It's like it kind of makes 0:02:22.960 --> 0:02:25.200 you feel cool watching it, you know what I mean? Well, 0:02:25.240 --> 0:02:27.840 I need that in my life. But the what the 0:02:27.880 --> 0:02:32.080 reason I raised style Wars is because the graffiti that 0:02:32.200 --> 0:02:34.760 was being carried out would not have ever been able 0:02:34.800 --> 0:02:38.359 to be done had it not been for a Norwegian 0:02:38.360 --> 0:02:43.680 engineer named Eric Rothheim who in put in the first 0:02:43.760 --> 0:02:47.359 patent for an aerosol can in Norway and then five 0:02:47.440 --> 0:02:50.000 years later the first one in the US. Yeah, and 0:02:50.040 --> 0:02:52.359 they had the little photo of some of his initial drawings, 0:02:52.400 --> 0:02:55.600 and the author of this article points out that although 0:02:56.160 --> 0:02:58.640 it has evolved somewhat, it's he's He was pretty right 0:02:58.680 --> 0:03:01.839 on with that first, is right, you know, almost out 0:03:01.840 --> 0:03:05.000 of the gate, because as we said, it's kind of simple. 0:03:05.560 --> 0:03:07.440 The Yeah, one of them was simple to me. One 0:03:07.440 --> 0:03:10.959 of them I didn't quite understand. Well, okay, so um 0:03:11.000 --> 0:03:13.800 so Rothheim he comes up with this, this patent files, 0:03:13.840 --> 0:03:16.840 it kicks back and waits for the money to come 0:03:16.919 --> 0:03:20.320 rolling in, but it doesn't. It took many many years 0:03:21.560 --> 0:03:25.200 or so maybe a little less before anyone fully understood 0:03:25.560 --> 0:03:29.839 the value of an aerosol can, and it was um insecticides, 0:03:29.960 --> 0:03:34.720 bug bombs, cans of um insects spray that was being 0:03:34.840 --> 0:03:37.200 used by soldiers in the Pacific and World War Two. 0:03:37.320 --> 0:03:42.160 When people finally said, oh, that is a good idea. Yeah, 0:03:42.160 --> 0:03:44.600 I wonder if I mean they had atomizers and things 0:03:44.640 --> 0:03:46.240 at the time. I wonder if that was his initial 0:03:46.280 --> 0:03:50.880 inspiration was to take that concept and jam it into 0:03:51.080 --> 0:03:56.040 a can basically, because that's what's going on. Yeah, you're 0:03:56.080 --> 0:04:01.160 atomizing product. Yeah, and there's a lot of um advantages 0:04:01.240 --> 0:04:03.840 to atomizing. Number one, if you spray something in a 0:04:03.880 --> 0:04:06.480 fine mist, it doesn't hit the ground. Is a bunch 0:04:06.480 --> 0:04:09.360 of liquid that seeks into the groundwater usually sticks to 0:04:09.400 --> 0:04:13.320 whatever you're spraying it to. Sure, and it's delightful if 0:04:13.400 --> 0:04:15.960 you wear perfume or have you ever like had the 0:04:16.040 --> 0:04:18.760 rose water sprayed on your face, like the face sprays. Oh, 0:04:18.800 --> 0:04:20.720 I thought you meant like an aerosol can of perfect 0:04:20.760 --> 0:04:25.600 no atomizing in general? Yeah, sure, sure, I'm fresh. I've 0:04:25.720 --> 0:04:29.039 I've had an avian sprits sprayed on my face. You 0:04:29.080 --> 0:04:30.920 mean I have before? It's very nice. Yeah, I've had 0:04:30.920 --> 0:04:33.719 like the rosewater. Emily will spraying me occasionally. It's very nice. 0:04:34.040 --> 0:04:36.239 It just feels good. Does she like hide behind around 0:04:36.279 --> 0:04:40.800 a corner and yeah, no, that's the mace. Oh she 0:04:40.880 --> 0:04:46.400 mazes me occasionally for kicks. Um. So yeah, there's advantages 0:04:46.440 --> 0:04:49.560 to atomizing things. There's reasons. It's at the very least 0:04:49.600 --> 0:04:54.560 it's lovely. It is um and the whole premise behind 0:04:54.680 --> 0:04:58.760 this though, the delivery method of an aerosol can Like 0:04:58.800 --> 0:05:01.200 we said, it's very basic, it's very old, and all 0:05:01.240 --> 0:05:03.599 you have to do is understand a little bit about 0:05:03.760 --> 0:05:08.760 fluid dynamics to to get what's going on. So let's 0:05:08.839 --> 0:05:11.360 let's do let's give a brief prime around fluid dynamic 0:05:11.400 --> 0:05:14.960 shall yeah, and fluid period Like you know, fluid isn't 0:05:14.960 --> 0:05:18.760 necessarily liquid like you might think it's an actual thing. 0:05:18.800 --> 0:05:22.400 Fluid is any kind of substance that has free flowing 0:05:22.440 --> 0:05:24.960 particles that it's made up of that and it could 0:05:24.960 --> 0:05:27.880 be something liquid, could be something gas that those are 0:05:27.920 --> 0:05:32.159 both fluids. It just can't be a solid basically pretty much. Yeah, yeah, 0:05:32.160 --> 0:05:35.279 as long as you got those free flowing particles. Um, 0:05:35.360 --> 0:05:38.440 these particles, uh, if it's a liquid, they're loosely bound, 0:05:38.440 --> 0:05:40.680 but they're still bound. So it means it's gonna have 0:05:40.680 --> 0:05:42.880 a fixed volume if it's a liquid. Yeah, which is why, 0:05:42.960 --> 0:05:46.119 like when you put water into a glass, it doesn't 0:05:46.160 --> 0:05:49.240 just keep going and going and going. That'd be terrifying. No, 0:05:49.560 --> 0:05:53.039 it would make it. It would have a gaseous um characteristic. 0:05:53.080 --> 0:05:55.919 Then that's right, because gas does expand to fill the 0:05:56.000 --> 0:05:58.919 volume that you put it in. That's right, and well, 0:05:59.320 --> 0:06:03.360 spoiler or that's what happens with gas. It expands. Uh, 0:06:03.400 --> 0:06:07.360 if you heat liquid um applying energy to it, basically 0:06:07.720 --> 0:06:11.800 it's gonna vibrate and it's gonna break those forces and 0:06:11.920 --> 0:06:13.960 they're not gonna be bound together anymore. Then you're gonna 0:06:13.960 --> 0:06:16.599 have a gas. And that's called boiling. Yeah. And I 0:06:16.600 --> 0:06:19.480 mean we think of boiling is like applying enough heat 0:06:19.520 --> 0:06:23.320 that you will burn your skin. But boiling points vary 0:06:23.400 --> 0:06:27.159 for different types of fluids. Um. So any volatile fluid 0:06:27.240 --> 0:06:30.279 is a fluid that um boils or turns from a 0:06:30.320 --> 0:06:33.400 liquid state to a gasy state. That's boiling um at 0:06:33.480 --> 0:06:36.719 room temperature, right, Yeah, Which that that's the part I 0:06:36.760 --> 0:06:39.000 had a hard time getting my head around because I 0:06:39.000 --> 0:06:42.040 associate boiling with like heat and hot. Yeah. Because you 0:06:42.040 --> 0:06:44.600 think of boiling, you think of water, Yeah, exactly. And 0:06:44.720 --> 0:06:48.159 it takes a certain amount of temperature, of heat of 0:06:48.320 --> 0:06:52.400 heat energy to break those intermolecular bonds to turn water 0:06:52.520 --> 0:06:55.359 from a liquid into a gas, that's right. But it 0:06:55.400 --> 0:06:58.520 takes less for alcohol or for propane or whatever you 0:06:58.600 --> 0:07:02.480 want to use. Right. And so lastly there's another fluid 0:07:02.560 --> 0:07:04.600 dynamic trait that we have to have down and then 0:07:04.640 --> 0:07:08.039 we'll have all of the stuff in place to understand 0:07:08.080 --> 0:07:12.200 an aerosol can expansion of gas. Yeah, So so we 0:07:12.240 --> 0:07:14.640 said that when you put gas into something and expands 0:07:14.680 --> 0:07:18.840 to fill the volume, Yeah, and gas will decrease in 0:07:18.880 --> 0:07:22.200 pressure as it expands, which is why like a tiny 0:07:22.240 --> 0:07:25.280 little CEO two cartridge, it's like got tons of pressure 0:07:25.320 --> 0:07:27.520 in there, and that's why it can shoot your awesome 0:07:28.280 --> 0:07:32.760 industrial arts model car down the track. Because did you 0:07:32.760 --> 0:07:36.760 ever do that? Really? I had a Pinewood Derby racer once. 0:07:37.760 --> 0:07:40.280 What's that like the car you sit in? No, that's 0:07:40.320 --> 0:07:43.200 the cub scout car. Okay, it didn't have any CEO 0:07:43.240 --> 0:07:46.640 two though you'd be immediately disqualified. Yeah. In high school, 0:07:46.640 --> 0:07:48.760 we we made the little cars that have the CEO 0:07:48.800 --> 0:07:50.760 two cartridge in the battle. I know what you're talking about. 0:07:50.800 --> 0:07:53.160 And we raced each other and my brother one county 0:07:53.240 --> 0:07:56.480 of course, and then and then flashed this winning smile, 0:07:56.720 --> 0:07:58.680 and three years later, it's so funny. I forgot all 0:07:58.680 --> 0:08:01.160 about this. I tried to be his car design when 0:08:01.200 --> 0:08:05.320 I took the class, and mine was not nearly as like, 0:08:06.680 --> 0:08:09.679 it just wasn't quite right, and I didn't win county. 0:08:09.720 --> 0:08:14.520 I didn't even win my classroom. Somehow, the the compressed 0:08:14.600 --> 0:08:17.600 air decompressing into the atmosphere made like a sad trombo 0:08:17.680 --> 0:08:20.000 and sad is it so cool? And that really kind 0:08:20.000 --> 0:08:21.880 of just sums it all up with my brother and I. 0:08:22.720 --> 0:08:24.559 He was always really great at stuff, and I always 0:08:24.600 --> 0:08:27.040 tried to do that and was not nearly as good 0:08:27.080 --> 0:08:29.960 at it. You're good at other things. Well, I'm yeah, 0:08:30.160 --> 0:08:33.920 I can run my mouth, if that's how you want 0:08:33.960 --> 0:08:37.320 to put it. Anyway, So that's compressed gas. And when 0:08:37.360 --> 0:08:39.760 gas is compressed, it can you know, do some great 0:08:39.760 --> 0:08:42.920 things like shoot the car or in this case, spray 0:08:42.920 --> 0:08:47.000 paint or something. Right, right, exactly, Okay, So you have 0:08:47.040 --> 0:08:49.560 compressed gas, you have all these fluid dynamics, and you've 0:08:49.600 --> 0:08:53.319 had everyone now right, Okay, So all an aerosol can 0:08:53.480 --> 0:08:56.040 is is all of these principles kind of put into 0:08:56.040 --> 0:09:02.760 a very simply mechanically functioning state. Right. Yeah. So you 0:09:02.800 --> 0:09:07.080 have a can and you have to to things in there. 0:09:07.240 --> 0:09:10.800 You have the propellant, which is the stuff you use 0:09:10.880 --> 0:09:14.640 to force the other thing, the product out. Yeah. And 0:09:14.720 --> 0:09:19.360 it could be hair spray, bug spray, could be painting oil, 0:09:19.520 --> 0:09:23.559 could be that foamy stuff you ever use that, the 0:09:23.600 --> 0:09:26.520 stuff to like seal like insulation or sure or like 0:09:26.600 --> 0:09:33.079 fix the flat. All that, all that has myriad myriad uses. Okay, right, So, um, 0:09:33.160 --> 0:09:36.760 you've got the product in liquid state. Yes, uh say, 0:09:36.760 --> 0:09:38.559 it's just kind of floating in the bottom of the can. 0:09:39.240 --> 0:09:43.120 You put it in the can, seal it so it's 0:09:43.160 --> 0:09:45.760 there's there's no air going it's air tight. Yeah, this 0:09:45.800 --> 0:09:47.559 is part one. There's two two ways to do this. 0:09:47.559 --> 0:09:49.440 This is the first, right, This is the simple way. 0:09:49.800 --> 0:09:53.720 And then you add some sort of compressed air to it, 0:09:53.960 --> 0:09:57.880 call it air compressed air. Okay, okay. So you have 0:09:58.000 --> 0:10:02.200 this um the propellant in there, and it's it's basically 0:10:02.280 --> 0:10:04.640 filling up as much of it as it can until 0:10:04.679 --> 0:10:06.599 it's reaching the top of the can, the side of 0:10:06.600 --> 0:10:08.240 the can, in the top of the water, and it 0:10:08.280 --> 0:10:10.720 pushes all that product down to the bottom, which is 0:10:10.720 --> 0:10:12.720 one reason you gotta shake it chack it up exactly. 0:10:13.240 --> 0:10:16.600 So you have a tube going down from the nozzle 0:10:16.960 --> 0:10:19.640 at the top of the can valve system all the 0:10:19.640 --> 0:10:22.240 way down to the bottom of the can where the 0:10:22.280 --> 0:10:25.560 liquid is right and that look, that valve has a 0:10:25.640 --> 0:10:29.319 seal that's being pushed up by a spring. So the 0:10:29.360 --> 0:10:32.559 head the nozzle when it's when it's not being pushed, 0:10:32.920 --> 0:10:35.840 it's stealed tight. But when you push it down a 0:10:35.960 --> 0:10:40.320 channel opens. It goes below the seal and you now 0:10:40.440 --> 0:10:43.559 have the outside atmosphere, which is at a much lower 0:10:43.559 --> 0:10:47.400 pressure than inside the can um opened up to the 0:10:47.440 --> 0:10:50.000 inside of the can at that much higher pressure, and 0:10:50.080 --> 0:10:53.120 it drives it up the tube out the little tiny, 0:10:53.160 --> 0:10:57.439 tiny hole which atomizes it. And that's basically the simpler 0:10:58.040 --> 0:11:00.560 method of the aerosol can. Yeah. The air pushes the 0:11:00.559 --> 0:11:02.839 liquid down and then up the tube. Yeah, because it's 0:11:02.880 --> 0:11:06.920 like I want to get out too exactly. It expands. Done. 0:11:07.000 --> 0:11:10.320 I mean that's pretty easy. Yeah. So the second way 0:11:10.400 --> 0:11:12.040 that this can happen, and I didn't know this is 0:11:12.040 --> 0:11:14.640 the more common way, but it is. Uh they use 0:11:14.720 --> 0:11:19.559 liquified gas, so uh, that is the propellant. You've still 0:11:19.600 --> 0:11:23.440 got the same product. And the product is is sitting 0:11:23.480 --> 0:11:25.640 there at room temperature just fine as a liquid. So 0:11:25.679 --> 0:11:28.079 they just pour that in. Then they steal it up, 0:11:28.120 --> 0:11:30.240 and then the same way with the other way. They 0:11:30.280 --> 0:11:35.280 pump in this liquefied gas and it mixes though this time, 0:11:35.400 --> 0:11:37.480 right or does it press it down? This is where 0:11:37.480 --> 0:11:39.920 I got a little confused. So a liquefied guess you said, 0:11:40.000 --> 0:11:43.160 is um, it's a gas that goes into a liquid 0:11:43.160 --> 0:11:45.280 state under a certain amount of pressure, right, yeah, okay, 0:11:45.400 --> 0:11:49.199 so under high pressure. Yeah, so it does mix because 0:11:49.200 --> 0:11:51.120 it's all liquid in there. Once it gets in there, 0:11:51.559 --> 0:11:53.800 the whole thing turns liquid, and you keep that pressure 0:11:53.880 --> 0:11:55.800 up so it doesn't have any room to expand, so 0:11:55.840 --> 0:11:59.000 it's just in their mix together. And then when you 0:11:59.040 --> 0:12:01.240 press the nozzle down own and you break the seal 0:12:01.280 --> 0:12:05.400 as it were, um, the you form a channel with 0:12:05.440 --> 0:12:07.199 the outside air and the inside air. That change in 0:12:07.240 --> 0:12:11.680 pressure converts some of that propellant into gas, and it 0:12:11.760 --> 0:12:14.240 does the same thing is that standard can. The gas 0:12:14.320 --> 0:12:18.520 presses down forces the liquid up, but some of that 0:12:18.600 --> 0:12:21.520 propellant is still in liquid form mixed with the product, 0:12:21.760 --> 0:12:26.200 and as it goes out, it evaporates, it turns into gas, 0:12:26.520 --> 0:12:30.040 and it also kind of um, it turns that liquid 0:12:30.120 --> 0:12:32.960 product into a finer miss. Yeah. But what I don't 0:12:32.960 --> 0:12:35.320 get is is that it actually boils in the liquid 0:12:35.320 --> 0:12:39.280 gas system. It's like, once you relieve that pressure, it 0:12:39.400 --> 0:12:41.840 starts to boil, and that's what does it. That's what 0:12:41.920 --> 0:12:43.600 I was a little confused about. Yeah, I have a 0:12:43.640 --> 0:12:47.760 feeling that this is a different part of fluid dynamics, 0:12:48.400 --> 0:12:51.760 that it's not necessarily the boiling point, although it could be, 0:12:51.760 --> 0:12:54.640 because I don't think any average gas turns into a 0:12:54.679 --> 0:12:58.960 liquid under under all under pressure. There's just certain kinds 0:12:59.000 --> 0:13:04.439 that do. I think. Okay, so I think, what's your question, Well, 0:13:04.440 --> 0:13:06.560 it's actually boiling in the second in the in the 0:13:06.600 --> 0:13:09.079 liquid gas type of aerosoli, at the very least, it's 0:13:09.120 --> 0:13:13.480 converting into a gassy estate because of the release of pressure, right, 0:13:13.520 --> 0:13:15.400 all right? And why did they can sometimes get cold? 0:13:15.440 --> 0:13:18.760 Did you figure that out? Okay? Boy, there's some guts. 0:13:18.800 --> 0:13:21.160 There's some people in chemistry lab right now that are 0:13:21.200 --> 0:13:25.040 just like, oh my god, you guys, I thought we 0:13:25.080 --> 0:13:27.320 had this one, man. I think we had we do 0:13:27.440 --> 0:13:28.880 I had it, and I could have done a tap 0:13:28.960 --> 0:13:31.200 dance doing this earlier, and now it's like, but wait, 0:13:31.280 --> 0:13:33.439 let me complicate it a little more. Now, I think 0:13:33.480 --> 0:13:36.280 it's I think the message got through. Um. If in 0:13:36.280 --> 0:13:38.680 the case of paint, sometimes you need a little help 0:13:39.280 --> 0:13:41.840 mixing these things together. So that's why a paint can, 0:13:42.080 --> 0:13:45.000 spray paint can will have the little metal ball bearing 0:13:45.120 --> 0:13:47.680 on the inside, right, because you actually do want to 0:13:47.720 --> 0:13:52.360 mix the propellant and the product together in a liquefied can, 0:13:52.440 --> 0:13:57.079 liquefied gas can, right, because it helps atomize it. As 0:13:57.120 --> 0:14:02.160 you said, that's very pleasant, exact. Um, what about the 0:14:02.240 --> 0:14:04.960 rounded bottom of this very can you know why that's 0:14:05.040 --> 0:14:08.720 that way? If it was flat, it's so pressurized, it 0:14:08.840 --> 0:14:11.040 could be a bad scene. It could actually go the 0:14:11.040 --> 0:14:15.160 other way. And everyone knows if you studied architecture, that 0:14:15.240 --> 0:14:19.560 a dome is more structurally sound than just a flat surface. 0:14:19.600 --> 0:14:22.360 So that's basically the same concept at play. So that's 0:14:22.360 --> 0:14:26.480 one reason, Um, it's to protect the integrity of the can. 0:14:26.960 --> 0:14:29.320 And the second one is is so you can help 0:14:29.360 --> 0:14:32.200 get all of the product out, because if it was flat, 0:14:32.280 --> 0:14:34.440 it's like when you're down at the bottom of your 0:14:34.960 --> 0:14:37.600 of your soda cup with your straw and you're making 0:14:37.600 --> 0:14:40.280 that terrible little noise and you're tilting the cup and 0:14:40.320 --> 0:14:42.320 trying to stick the straw on the little corner where 0:14:42.320 --> 0:14:44.400 it meets the edge. This does it for you. If 0:14:44.400 --> 0:14:46.880 it's a rounded bottom, it just puts all the product 0:14:46.920 --> 0:14:49.160 there at the edge and that's where the little tube is, 0:14:49.400 --> 0:14:51.920 and so you're all set. Yeah, And did you know 0:14:52.000 --> 0:14:55.640 there's about nineteen billion steel and aluminum cans that include 0:14:55.640 --> 0:14:58.600 aerosols and other products that are recycled every year and 0:14:58.640 --> 0:15:04.400 that's equal to enough to build twenty golden gate bridges. Wow, 0:15:04.720 --> 0:15:07.960 isn't that amazing? So we mentioned there's a variety of 0:15:07.960 --> 0:15:10.360 different products that you can have that you're trying to 0:15:11.440 --> 0:15:13.880 get out of your can, from foam to like whipped 0:15:13.880 --> 0:15:17.360 cream to a bug spray, stuff like that hair spray, 0:15:17.400 --> 0:15:20.920 although does anyone still use aerosol hair spray? I think 0:15:20.960 --> 0:15:24.400 some people do, is it? Remember? Do you remember the 0:15:24.440 --> 0:15:29.680 Bizarre Ways to Die episode? The deodorant boy asol deodorant 0:15:29.680 --> 0:15:33.480 that he died totally man, that was a long time ago. Um. 0:15:33.520 --> 0:15:35.720 So the way they accomplished this though with a different product, 0:15:35.920 --> 0:15:39.000 um is you can have a variety of consistencies. And 0:15:39.040 --> 0:15:42.600 what they do is they just play with, UM, the 0:15:42.720 --> 0:15:46.200 ratio propellant to product. Maybe maybe the chemical makeup of 0:15:46.200 --> 0:15:48.760 the propellant the product have to be just right. Maybe 0:15:48.800 --> 0:15:50.520 the pressure of the propellant has to be a little 0:15:50.520 --> 0:15:52.840 different depending on what kind of product you're working with. 0:15:53.320 --> 0:15:57.440 And then um, the size and shape of the valve system. 0:15:57.480 --> 0:15:59.320 Like in the case of a fix, the flat that 0:15:59.360 --> 0:16:01.840 you put in your higher it's not the same as 0:16:01.920 --> 0:16:04.480 you know, a spray can. It's not atomizing. It's got 0:16:04.480 --> 0:16:07.800 like the tube hooked up and it's Uh. If you've 0:16:07.800 --> 0:16:09.960 ever sprayed that stuff in your house, like the Philip Crack, 0:16:10.520 --> 0:16:12.560 like a whole can of it, It's amazing how much 0:16:12.560 --> 0:16:15.240 stuff is packed in there. Like when it gets out, 0:16:15.240 --> 0:16:17.240 you're just like wow, it's like the clown car of 0:16:17.280 --> 0:16:22.680 the industrial engineering scene. Um, do you want to know 0:16:22.720 --> 0:16:25.720 a little bit about CFC's chlorofluora carbons. Yeah, I didn't 0:16:25.720 --> 0:16:27.160 get a chance to look into this, but I'm glad 0:16:27.160 --> 0:16:31.600 you did so. Prior to the late twenties, there was 0:16:31.960 --> 0:16:36.240 people were using ammonia and refrigerators and dying from ammonia leaks, 0:16:36.280 --> 0:16:39.480 and it was just a bad scene. And so everybody said, well, 0:16:39.560 --> 0:16:41.840 we've got to figure out some sort of toxic, non 0:16:41.920 --> 0:16:45.360 toxic chemical that we can use as a refrigerant, and 0:16:45.440 --> 0:16:48.480 a general motors engineer of all people came up with 0:16:48.800 --> 0:16:53.000 what du Pont later turned into free on, a chlorofluora 0:16:53.040 --> 0:16:56.840 carbon which supposedly was non toxic. It was. It basically 0:16:56.920 --> 0:17:01.880 changed everything. Um it was much less harm harmful compared 0:17:01.920 --> 0:17:06.000 to like ammonia. UM. It allowed us to make cheap refrigerators, 0:17:06.800 --> 0:17:10.280 car A C, A C window units, like all those 0:17:10.280 --> 0:17:13.760 things came from the advent of chlorofluora carbons, right, And 0:17:14.080 --> 0:17:17.720 it was also very ubiquitous as a propellant in aerosol 0:17:17.800 --> 0:17:21.800 can sprays. Well. I think that's why everyone, you know 0:17:21.960 --> 0:17:25.840 quit using aquinette, right, because everybody was going in the 0:17:25.920 --> 0:17:28.080 spraying these things, and they were going up in the atmosphere, 0:17:28.119 --> 0:17:29.720 and everyone was like, look at them. Go it's cool. 0:17:29.800 --> 0:17:34.040 They're like, you know, innert, non toxic chemicals going up 0:17:34.040 --> 0:17:36.760 in the atmosphere, but we're all getting cancer. The problem 0:17:36.920 --> 0:17:40.840 is when a CFC enters the atmosphere and gets high 0:17:40.920 --> 0:17:44.439 enough and it's exposed to UV radiation, it breaks down 0:17:44.680 --> 0:17:47.840 and into its constituting components, one of which is chlorine, 0:17:48.280 --> 0:17:52.359 chlorine reeks, havoc on the ozone layer. One atom of 0:17:52.440 --> 0:17:56.359 chlorine can destroy about a hundred thousand ozone molecules, and 0:17:56.400 --> 0:17:59.000 we need those molecules. The ozone layer protects us from 0:17:59.240 --> 0:18:01.399 UVB ray from the sun, which are they kind of 0:18:01.520 --> 0:18:04.480 give you skin cancer and destroyed crops. So in nineteen 0:18:04.560 --> 0:18:07.760 seventy four some scientists realized that CFCs were doing this 0:18:07.880 --> 0:18:09.800 in the ozone layer and is gonna be big trouble. 0:18:11.080 --> 0:18:13.440 And then in the eighties we figured out that there's 0:18:13.440 --> 0:18:17.080 a hole in the ozone layer over the Arctic. So, uh, 0:18:17.280 --> 0:18:20.720 a bunch of countries I think seventies signed on to 0:18:21.359 --> 0:18:26.119 basically outlaw CFC production. Yeah, and then later on another 0:18:26.400 --> 0:18:30.560 like hundred and twenty I think signed another treaty. So 0:18:30.960 --> 0:18:34.600 it's very very difficult to find CFC's these days. But 0:18:34.680 --> 0:18:37.200 they're still around, are they. Yeah? They still use them 0:18:37.200 --> 0:18:41.800 in some um nasal sprays UM and they're also used 0:18:41.880 --> 0:18:47.720 in halan, which is a fire extinguisher for airplanes. Did 0:18:47.720 --> 0:18:51.680 they not still use free on? No? I don't believe. So, Okay, Yeah, 0:18:51.680 --> 0:18:53.880 it's basically like we did away with those. It's gonna 0:18:53.880 --> 0:18:55.480 take a while to repair. But they found that the 0:18:55.480 --> 0:18:57.920 ozone layers no longer growing the hole in the ozon 0:18:58.000 --> 0:19:02.399 layers growing, it's just holding steady and hopefully patching itself 0:19:02.440 --> 0:19:04.320 back up. They just forced people to go out and 0:19:04.320 --> 0:19:07.080 be innovative and find different ways to do these things exactly. 0:19:07.119 --> 0:19:11.240 And if you compare your airsol can propellant today to 0:19:11.440 --> 0:19:13.920 one that had CFCs before, you're not going to notice 0:19:13.960 --> 0:19:17.120 the least bit different. So that's canna aquinit that looks 0:19:17.160 --> 0:19:20.439 exactly the same as it did in nineteen seven is 0:19:20.520 --> 0:19:24.480 no longer dangerous, not to the ozone layer. It is 0:19:24.520 --> 0:19:28.480 the spiders though, if you have a lighter. Yeah, don't 0:19:28.480 --> 0:19:31.920 ever do that. Kids. Ah, that's it for airsol cans 0:19:32.000 --> 0:19:35.000 unless you have like another ten minutes on it. Uh No, 0:19:35.200 --> 0:19:36.879 that's all I got. I mean, what else is there? 0:19:37.520 --> 0:19:41.000 I genuinely looked in There is nothing else. Ye, go 0:19:41.040 --> 0:19:43.840 out and do some graffiti, That's what I say. Um 0:19:44.840 --> 0:19:47.600 artful graffiti though, don't tagg and stuff. You should probably 0:19:47.640 --> 0:19:50.480 practice at home first. I hate that. Just stupid. Yeah, Like, 0:19:51.920 --> 0:19:55.280 educate yourself on different types of nozzles, like practice, don't 0:19:55.280 --> 0:19:59.359 do don't be a punk, agreed, be an artiste. Uh. 0:19:59.400 --> 0:20:01.920 If you we want to learn more about aerosols, or 0:20:01.920 --> 0:20:03.600 at the very least, want to see the article where 0:20:03.600 --> 0:20:05.760 we told you everything there is to know about aerosolis. 0:20:05.760 --> 0:20:08.040 You can type that word A E R O S 0:20:08.080 --> 0:20:10.840 O L S into the search bar how stuffworks dot 0:20:10.840 --> 0:20:13.160 com and that will bring it up. And I said 0:20:13.160 --> 0:20:18.880 the search bar, which means it's time for message break 0:20:23.240 --> 0:20:25.520 and now it's time for listener mail. I thought you 0:20:25.600 --> 0:20:30.440 might say it, okay, Josh, listener mail time. UM, I'm 0:20:30.440 --> 0:20:35.879 gonna call this uh police sketch eye witnessed stuff. It's 0:20:35.920 --> 0:20:39.119 from Terry Bennett. Um, Hey, guys, uh listen to the 0:20:39.119 --> 0:20:41.600 police Sketch episode, and wanted to share my story. I 0:20:41.720 --> 0:20:43.320 was robbed when I was a teller of a bank 0:20:43.640 --> 0:20:46.919 in n and at that time, bank robbery was a 0:20:46.920 --> 0:20:50.200 federal crime, probably still is. I was immediately taken into 0:20:50.280 --> 0:20:53.280 the back room of the vault and the FBI was 0:20:53.359 --> 0:20:55.760 called in. When they arrived, a sketch artist brought a 0:20:55.840 --> 0:20:59.440 large binder, not full of women, but full of pictures. 0:20:59.800 --> 0:21:03.439 They aces and eyes and noses and mouths, et cetera. 0:21:04.240 --> 0:21:07.960 Transparencies of face shapes were the base, and the rest 0:21:07.960 --> 0:21:10.400 of the face was built on the base, one eye 0:21:10.400 --> 0:21:12.919 and nose at a time. UM I was not allowed 0:21:12.920 --> 0:21:15.040 to talk to anyone, including the staff of my bank, 0:21:15.119 --> 0:21:17.800 until I talked to the FBI. I was instructed to 0:21:17.800 --> 0:21:19.800 write everything I could remember about the robber and the 0:21:19.840 --> 0:21:23.400 robbery before talking to anybody else. In those days, of course, 0:21:23.440 --> 0:21:25.239 we did not have digital cameras in the film had 0:21:25.240 --> 0:21:28.600 to be sent out for processing. Um, all of it 0:21:28.800 --> 0:21:31.920 in those days. I mean, it's the same like seven 0:21:32.160 --> 0:21:37.000 years ago. Um. Actually when did digital come around? The 0:21:37.040 --> 0:21:39.840 early two thousands? Seems like it became. I guess it's 0:21:39.840 --> 0:21:45.760 more than seven three years on. So uh. The pictures 0:21:45.760 --> 0:21:47.240 took a couple of days to get back, and my 0:21:47.320 --> 0:21:50.399 composite drawing was posted in the paper, and my robber 0:21:50.480 --> 0:21:53.040 was actually caught a couple of days afterward at a 0:21:53.119 --> 0:21:56.320 methodon clinic in town. When the film was developed, the 0:21:56.440 --> 0:21:59.760