WEBVTT - Rerun: How Tech Could Make Better Chocolate 0:00:04.240 --> 0:00:07.240 Welcome to tech Stuff, a production of I Heart Radios 0:00:07.320 --> 0:00:13.760 How Stuff Works. Hey there, and welcome to tech Stuff. 0:00:13.800 --> 0:00:16.680 I'm your host, Jonathan Strickland. I'm an executive producer with 0:00:16.720 --> 0:00:20.040 I Heart Radio and I love all things tech, and guys, 0:00:20.520 --> 0:00:23.959 things have gotten a little hectic over at I Heart 0:00:24.040 --> 0:00:27.560 Radio headquarters. We're running around all over the place working 0:00:27.560 --> 0:00:32.600 on special projects. And the way it impacts us right now, guys, 0:00:32.840 --> 0:00:35.040 is that I just haven't had the time to be 0:00:35.080 --> 0:00:38.879 able to research and write full new episodes. So we're 0:00:38.880 --> 0:00:42.159 gonna be doing a couple of reruns just for the 0:00:42.200 --> 0:00:44.760 time being. Don't worry. New episodes are right around the corner. 0:00:45.440 --> 0:00:47.240 I just I need to be in the same city 0:00:47.479 --> 0:00:50.040 for two days in a row and then I think 0:00:50.080 --> 0:00:53.000 I can probably you know, bang a couple out. But 0:00:53.040 --> 0:00:56.280 in the meantime, I thought maybe we would enjoy this episode, 0:00:56.280 --> 0:00:59.080 which originally aired back in two thousand sixteen. It's called 0:00:59.280 --> 0:01:02.960 How Tech Could Make Better Chocolate, and it's all about 0:01:03.000 --> 0:01:07.240 a a Temple University project in which scientists were using 0:01:07.240 --> 0:01:11.039 electric fields to improve chocolate. And you know, being the 0:01:11.080 --> 0:01:14.080 holiday season with lots of chocolate all around, I figured 0:01:14.319 --> 0:01:17.480 what better time to revisit this than Now, so enjoy 0:01:17.760 --> 0:01:22.160 this classic episode. How Stuff Works Now if you aren't familiar, 0:01:22.440 --> 0:01:26.319 is our more news oriented page, So if you go 0:01:26.360 --> 0:01:28.920 to now dot how stuff works dot com you can 0:01:28.959 --> 0:01:31.640 see it. We have a lot more stories that are 0:01:32.280 --> 0:01:36.120 reflective of things that are unfolding now, thus the name, 0:01:36.560 --> 0:01:38.840 and we also do video for that. There's also a 0:01:38.840 --> 0:01:42.800 podcast hosted by Lauren Vogelbaum. You can subscribe to that 0:01:42.840 --> 0:01:44.760 How Stuff Works Now. It's a summary of some of 0:01:44.760 --> 0:01:48.400 the stories that we cover each week. So if you're 0:01:48.440 --> 0:01:51.840 not familiar with that, go check it out. It's pretty awesome. Anyway, 0:01:52.360 --> 0:01:56.320 I did this story about chocolate and making sure you 0:01:56.360 --> 0:01:59.760 could reduce the viscosity of liquid chocolate so that it 0:01:59.800 --> 0:02:02.640 does and gum up stuff because one of the challenges 0:02:02.640 --> 0:02:05.240 of working with chocolate is making sure that it doesn't 0:02:05.320 --> 0:02:08.919 clog up the pipes like Augustus Gloop in Willy Wonka. 0:02:09.040 --> 0:02:14.120 So a consulting firm working on behalf of Mars Incorporated, 0:02:14.320 --> 0:02:17.800 which is a giant candy company that makes a lot 0:02:17.840 --> 0:02:21.600 of different chocolate products. This consulting firm went to a 0:02:21.639 --> 0:02:25.240 group of physicists at Temple University, and physicist is one 0:02:25.280 --> 0:02:29.639 of those words. I have difficulty pronouncing. I think I 0:02:29.720 --> 0:02:32.880 might just say scientists. Scientists at Temple University. Hey, that's 0:02:32.880 --> 0:02:35.760 way better. And these guys have developed a method to 0:02:35.840 --> 0:02:42.000 make crude oil flow more easily through pipes using electric fields. 0:02:42.080 --> 0:02:45.000 So the question that the consulting firm had was could 0:02:45.040 --> 0:02:47.000 you do the same thing you did for crude oil 0:02:47.080 --> 0:02:51.040 for chocolate? And here's a spoiler alert, Yeah they could. 0:02:51.680 --> 0:02:54.120 But I want to talk more about what they did 0:02:54.200 --> 0:02:56.240 and how they did it because it's it's a really 0:02:56.320 --> 0:03:01.480 interesting story. So I'm gonna go into a bit more 0:03:01.520 --> 0:03:06.079 detail about the physics and the technology behind the scientist 0:03:06.200 --> 0:03:09.040 solution for this problem. It's pretty cool and a lot 0:03:09.080 --> 0:03:11.800 of it was stuff I had no idea about before 0:03:11.840 --> 0:03:14.079 I began to research the story. So today's episode is 0:03:14.120 --> 0:03:18.840 going to be about chocolate. It's gonna be about viscous fluids, 0:03:18.880 --> 0:03:23.519 about electro real logical fluids, and how an electric field 0:03:23.560 --> 0:03:28.360 can change their fluid I properties, specifically viscosity. So yeah, 0:03:28.400 --> 0:03:31.079 this episode is gonna be science heavy. But here's also chocolate, 0:03:31.160 --> 0:03:34.839 so stick around. You know, everyone loves chocolate. So let's 0:03:34.840 --> 0:03:39.480 get into the physics first. Now, fluid dynamics is pretty 0:03:39.520 --> 0:03:43.080 complicated and also there's some stuff that's related to this 0:03:43.200 --> 0:03:47.920 that falls into the category of misinformation about viscosity. So 0:03:48.480 --> 0:03:51.920 I'll be talking a lot about not just the principles 0:03:51.920 --> 0:03:56.040 in general, but some specific uh myths that I would 0:03:56.040 --> 0:04:00.680 like to bust, as some of my former workers used 0:04:00.680 --> 0:04:03.480 to do on a regular basis. So, first of all, 0:04:03.560 --> 0:04:07.240 viscosity is a property of fluids or semi fluids, and 0:04:07.400 --> 0:04:11.320 it can be described as a fluids thickness or stickiness 0:04:11.320 --> 0:04:16.680 and its resistance to flowing due to internal friction. More accurately, 0:04:16.800 --> 0:04:19.480 viscosity is a measure of the resistance of a fluids 0:04:19.480 --> 0:04:25.000 deformation due to tensile or shear stress. Now, shear stress 0:04:25.080 --> 0:04:30.120 is mechanical stress that's parallel to the surface of that substance. 0:04:30.640 --> 0:04:36.280 So you could think of sheer stress as it's not perpendicular. 0:04:36.320 --> 0:04:38.720 It's not like an impact, right, it's more of a 0:04:38.760 --> 0:04:42.280 tearing ten style. Stress is a pulling stress rather than 0:04:42.320 --> 0:04:47.200 a compression stress. So again, instead of compressing stuff closer together, 0:04:47.240 --> 0:04:50.560 it's about pulling stuff further apart. And water has a 0:04:50.560 --> 0:04:56.200 pretty low viscosity, Honey has a very high viscosity. So 0:04:56.279 --> 0:05:00.159 we actually measure viscosity and units called poises p o 0:05:00.400 --> 0:05:04.360 I s e s. Water at room temperature twenty degrease 0:05:04.400 --> 0:05:08.680 celsius or so has a viscosity of zero point zero 0:05:09.000 --> 0:05:12.960 one poises or a center poise. In other words, a 0:05:13.080 --> 0:05:17.720 thick oil might have a viscosity of one point zero poise. Now, 0:05:17.760 --> 0:05:22.320 we measure viscosity with a viscometer. I'm not making that up. 0:05:22.839 --> 0:05:25.520 That's actually the name of the tool used to measure 0:05:25.520 --> 0:05:30.960 a fluids viscosity. Now, typically we will call a liquid 0:05:31.320 --> 0:05:34.920 viscous if its viscosity is higher than that of waters, 0:05:35.360 --> 0:05:38.200 and if the viscosity is lower than that of waters, 0:05:38.240 --> 0:05:41.800 because water is not the least viscous material that we 0:05:41.839 --> 0:05:44.440 know of, if it has a lower viscosity than water, 0:05:44.520 --> 0:05:48.480 we call that fluid mobile. So some fluids are so 0:05:48.640 --> 0:05:51.479 viscous that they can actually seem to be a solid. 0:05:51.680 --> 0:05:55.919 And this leads us to that misinformation I was talking about. 0:05:55.960 --> 0:05:59.240 It's one of those things that I hear bandied about 0:05:59.680 --> 0:06:02.359 prey the well, not not not as frequently as it 0:06:02.480 --> 0:06:06.040 used to, but it's one of those miss understandings that 0:06:06.120 --> 0:06:08.359 gets passed around its fact every now and again, and 0:06:08.400 --> 0:06:12.000 that is the idea that glass is one of these 0:06:12.000 --> 0:06:15.520 fluids that glass is actually a fluid that is um 0:06:15.600 --> 0:06:18.159 so viscous that it appears to be a solid, and 0:06:18.240 --> 0:06:23.400 that is not true. Glass is not a very very 0:06:23.520 --> 0:06:28.240 viscous fluid. It's a little more complicated than that. Uh So, 0:06:28.880 --> 0:06:31.400 here's the basic idea. People have noticed that if they 0:06:31.480 --> 0:06:35.960 look at windows and very old buildings like medieval churches, 0:06:36.640 --> 0:06:41.239 they see that the base of the window is thicker 0:06:41.279 --> 0:06:45.200 than the top of the window. And this has led 0:06:45.279 --> 0:06:50.240 some people to conclude, to jump to a conclusion that 0:06:50.320 --> 0:06:52.679 the reason why the base is thicker than the top 0:06:52.839 --> 0:06:56.760 is that glass, over the course of centuries has been 0:06:56.760 --> 0:07:01.320 flowing downward and that it's so low that it's not 0:07:01.480 --> 0:07:05.680 detectable under normal situations. It's only over the course of 0:07:05.800 --> 0:07:09.359 centuries that you can see the difference. Uh. Here's the 0:07:09.360 --> 0:07:12.640 problem is that that's just not that's not the case. 0:07:12.680 --> 0:07:17.040 That's not true. It's not what's happening. Uh. If you 0:07:17.400 --> 0:07:21.800 look at the glass making approach in the Middle Ages, 0:07:21.880 --> 0:07:25.600 you'll see why there's a thicker part of the pane 0:07:25.640 --> 0:07:29.440 of glass. Glass was created generally speaking, in the Middle 0:07:29.480 --> 0:07:34.240 Ages through something called the crown glass process. It's a 0:07:34.240 --> 0:07:38.120 pretty neat idea pretty neat way of making glass windows. 0:07:38.480 --> 0:07:41.400 Here's how it worked in general. First, you get your 0:07:41.440 --> 0:07:45.280 raw materials to make glass, and in the Middle Ages 0:07:45.360 --> 0:07:48.440 that was essentially sand and potash, and you mix it 0:07:48.480 --> 0:07:51.600 together and you melt them in a very hot furnace. 0:07:52.800 --> 0:07:55.680 Then you would get a glass blower with a pipe 0:07:55.960 --> 0:07:59.400 and they would get roll out a lump of molten glass, 0:07:59.400 --> 0:08:02.720 put on the ype blow out the glass. So they 0:08:02.760 --> 0:08:07.120 expand the glass outward before flattening it, so they don't 0:08:07.160 --> 0:08:09.920 just you know, create a globe of glass, they actually 0:08:09.920 --> 0:08:12.640 flatten it back out. Then, with the flat glass, which 0:08:12.680 --> 0:08:16.200 is still hot and still malleable, it hasn't cool to 0:08:16.240 --> 0:08:19.360 the point where it is really solidified, you would put 0:08:19.360 --> 0:08:22.240 that on a disk, a spinning disk, and the disk 0:08:22.320 --> 0:08:25.520 spins around to draw out the glass to flatten it further. 0:08:26.320 --> 0:08:29.000 Sort of like how a pizza maker will toss and 0:08:29.080 --> 0:08:31.640 spend dough in the air in order to make that 0:08:31.760 --> 0:08:35.440 circular pizza. It's kind of similar to that. So the 0:08:35.520 --> 0:08:39.599 disc spins and the centripetal force, if you like this, 0:08:39.720 --> 0:08:44.120 pushing the glass outward toward the edges. So then once 0:08:44.160 --> 0:08:48.480 that's done, you would cut the glass into panes so 0:08:48.520 --> 0:08:51.480 that you could fit them in a window. Now, that 0:08:51.480 --> 0:08:53.760 would mean that when you would get anywhere close to 0:08:53.760 --> 0:08:57.360 where the edge of the glass was, the outer edge, 0:08:57.480 --> 0:08:59.120 because you put the glass on that disk and you 0:08:59.120 --> 0:09:02.760 spun it around, the outer edge was thicker than the 0:09:02.800 --> 0:09:06.160 rest of the glass, just because that's where the excess 0:09:06.160 --> 0:09:10.600 was accumulating as it was being uh pushed outward due 0:09:10.600 --> 0:09:15.280 to the spinning motion. So typically window makers would cut 0:09:15.360 --> 0:09:18.360 pains so that a thicker edge would only be on 0:09:18.360 --> 0:09:20.840 one side, and they put that side at the bottom 0:09:20.880 --> 0:09:24.160 at the base of the window, so glass didn't flow 0:09:24.320 --> 0:09:27.440 to the base over hundreds of years. It started out 0:09:27.559 --> 0:09:30.400 like like that. It was like that from the beginning. 0:09:30.960 --> 0:09:34.240 That being said, glass is a really interesting substance. It's 0:09:34.280 --> 0:09:38.520 what we would call an amorphous solid, so saying that 0:09:38.559 --> 0:09:42.120 it's a fluid or a liquid is not accurate. But 0:09:42.320 --> 0:09:46.160 it is an amorphous solid, which is a little hinky 0:09:46.280 --> 0:09:48.800 compared to other materials that you might be familiar with. 0:09:49.160 --> 0:09:54.760 So typically not everything, obviously metals and glass being exceptions, 0:09:54.800 --> 0:09:57.480 but a lot of solids have an ordered crystalline structure, 0:09:58.400 --> 0:10:00.959 so that means the molecules are organized in a pretty 0:10:00.960 --> 0:10:08.160 regular lattice. They form a nice repeating pattern that goes 0:10:08.200 --> 0:10:12.840 throughout the entire material. When you heat up this solid, 0:10:13.800 --> 0:10:16.440 those molecules start to shimmy and shake. Some of the 0:10:16.440 --> 0:10:18.760 molecular bonds might start to break down a little bit, 0:10:19.600 --> 0:10:23.800 the bonds between one molecule and another. The essentially the 0:10:23.840 --> 0:10:27.079 crystalline order breaks down. And if you heat a solid 0:10:27.120 --> 0:10:30.160 beyond its melting point, the crystalline structure completely breaks down 0:10:30.200 --> 0:10:34.000 and molecules will begin to flow freely, or as freely 0:10:34.040 --> 0:10:37.640 as the viscosity of that fluid allows, and there's a 0:10:37.760 --> 0:10:42.120 very clear delineation between the solid and liquid stages. You 0:10:42.120 --> 0:10:47.719 can see the difference molecularly from the way this substance 0:10:47.760 --> 0:10:50.720 looks when it's in solid form versus in liquid form, 0:10:50.760 --> 0:10:54.120 and we call that delineation that border between the two 0:10:54.280 --> 0:10:59.560 the first order phase transition. It's obvious when you look 0:10:59.600 --> 0:11:03.280 at it from a microscopic standpoint. I mean it's obvious 0:11:03.280 --> 0:11:07.199 from a macroscopic standpoint too, because a solid behaves one way, 0:11:07.200 --> 0:11:10.640 in a liquid behaves another way. Now, when you cool 0:11:10.880 --> 0:11:16.040 a liquid down, its viscosity tends to increase. If you 0:11:16.080 --> 0:11:20.199 introduce a nucleation site into the liquid, crystals can form 0:11:20.480 --> 0:11:23.720 and you get that nice solid structure again, once you 0:11:23.760 --> 0:11:27.720 get down below what the melting point was. Uh, but 0:11:27.840 --> 0:11:32.760 glass doesn't do this. Glass doesn't form a crystalline structure. 0:11:33.679 --> 0:11:37.959 Glasses viscosity increases, so it does what other fluids do 0:11:38.080 --> 0:11:42.480 at that point. But since it doesn't crystallize, it solidifies 0:11:42.520 --> 0:11:46.199 in a different way. The molecules actually form an irregular arrangement, 0:11:46.840 --> 0:11:50.599 not that nice ordered structure that you see another solids, 0:11:50.640 --> 0:11:53.880 but that a regular arrangement is still cohesive enough to 0:11:54.000 --> 0:11:59.320 maintain rigidity. So glass does become a solid, It's just 0:11:59.400 --> 0:12:04.320 not a crysp let solid. It's an amorphous solid. Jonathan 0:12:04.320 --> 0:12:07.000 from two thousand nineteen breaking in to say, we'll be 0:12:07.160 --> 0:12:18.000 right back after this quick break. Now, there's no first 0:12:18.080 --> 0:12:20.800 order phase transition here. It's not like if you looked 0:12:20.800 --> 0:12:23.600 at the liquid form of glass and the solid form 0:12:23.600 --> 0:12:26.439 of glass, you would see a massive difference in the 0:12:26.640 --> 0:12:31.920 molecular structure. But there is a second order transition. Now. 0:12:31.920 --> 0:12:34.600 That transition is a little more subtle than first order 0:12:34.679 --> 0:12:39.240 transitions and involves the thermal expansion and heat capacity of 0:12:39.280 --> 0:12:44.000 a material, so it wouldn't be as obvious to casual 0:12:44.120 --> 0:12:48.440 observation on a microscopic level, but there would still be 0:12:48.480 --> 0:12:54.000 differences with the thermodynamics of the material, so we still 0:12:54.000 --> 0:12:56.240 would say the glass is a solid, not a liquid. 0:12:56.760 --> 0:12:59.360 All right, I'm done with glass now, I promise. I 0:12:59.360 --> 0:13:01.680 had to go on that little track just because it 0:13:01.679 --> 0:13:03.719 was related to the stuff I was talking about, and 0:13:04.080 --> 0:13:06.880 I get really irritated seeing that one myth passed around 0:13:06.880 --> 0:13:09.080 as fact. So now you know, if you ever go 0:13:09.200 --> 0:13:13.200 through a a tour and the tour guide says and 0:13:13.240 --> 0:13:15.680 the reason that the windows are thicker at the bottom 0:13:15.720 --> 0:13:18.160 is because glass flows over the course of hundreds of years, 0:13:18.480 --> 0:13:23.040 you can raise your hand and say, well, actually, and 0:13:23.080 --> 0:13:25.000 tell them Josh Clark sent you, because I don't want 0:13:25.000 --> 0:13:27.040 that kind of burden on me. I like being able 0:13:27.080 --> 0:13:32.080 to take tours. Anyway, Let's get back to viscosty in general. So, 0:13:32.160 --> 0:13:35.640 like I said earlier, viscosty is due to internal friction 0:13:35.760 --> 0:13:38.800 of a liquid. And you might think that that sounds weird, 0:13:38.880 --> 0:13:41.480 like how can a liquid have friction inside of it? 0:13:41.760 --> 0:13:45.880 But we're talking about liquids specifically that have like molecules, 0:13:45.880 --> 0:13:48.480 and those molecules can have a tendency to resist getting 0:13:48.559 --> 0:13:52.400 by each other. So some molecules are more resistant to 0:13:53.600 --> 0:13:56.319 slipping by each other than others, or a liquid could 0:13:56.360 --> 0:13:58.520 actually have particles that are suspended in it. It could 0:13:58.520 --> 0:14:02.240 be a suspension, which is different than just a pure liquid. 0:14:03.440 --> 0:14:07.720 But if it's a suspension, it's got particles suspended within 0:14:08.320 --> 0:14:12.520 the liquid at some level of density, right Like some 0:14:12.920 --> 0:14:14.960 maybe a pretty weak suspension where you don't have a 0:14:14.960 --> 0:14:20.160 whole lot, but others could have a greater density of 0:14:20.240 --> 0:14:24.720 particles inside a suspension of fluid. Make chocolate bars, let's say, 0:14:25.080 --> 0:14:28.920 and you're laying out melted chocolate into the mold for 0:14:28.960 --> 0:14:31.800 the chocolate bars, uh, and it clogs up and you 0:14:31.840 --> 0:14:34.320 have to stop production and clean out the clog and 0:14:34.600 --> 0:14:36.960 get everything back up to temperature and start it all 0:14:36.960 --> 0:14:40.960 over again. It's time consuming and expensive when that happens. 0:14:41.400 --> 0:14:45.280 So one solution to preventing it from happening is dilute 0:14:45.320 --> 0:14:49.080 the cacao more so that those particles don't clump up 0:14:49.080 --> 0:14:54.760 as much because there there's a less dense coco component 0:14:54.880 --> 0:14:59.280 in the fluid. That essentially means replacing cacao with something else, 0:14:59.400 --> 0:15:03.760 typically something that is less viscous, like that oil that 0:15:03.920 --> 0:15:07.560 fat essentially, so you usually add more fat to the 0:15:07.600 --> 0:15:12.120 recipe so you get the more fat but less cacao. However, 0:15:12.200 --> 0:15:16.520 it ends up flowing better and creates the chocolate bars 0:15:16.560 --> 0:15:19.920 that you want without creating the clogs. But it's not 0:15:19.960 --> 0:15:23.160 necessarily the best product you could create. It's just the 0:15:23.200 --> 0:15:28.320 most convenient based upon the method of production. So that's 0:15:28.320 --> 0:15:31.240 where this alternative solution comes in. If you could change 0:15:31.480 --> 0:15:35.280 the shape of those cacao particles in the fluid so 0:15:35.320 --> 0:15:40.320 that they packed together more effectively, you would reduce that viscosity, 0:15:40.400 --> 0:15:44.880 that internal friction of the fluid. So imagine you've got 0:15:44.880 --> 0:15:48.000 one of those inflated rubber balls, like like a kickball 0:15:48.120 --> 0:15:51.520 or something. Now, imagine that you're able to grab hold 0:15:51.720 --> 0:15:56.400 on either side of this ball and pull it outward 0:15:56.720 --> 0:16:00.240 so that you're elongating it. Now it would become a 0:16:00.360 --> 0:16:04.880 more of an oval shape, or as the researchers at 0:16:04.920 --> 0:16:10.760 Temple University called them, prolate spheroids. Now, the interesting thing 0:16:10.840 --> 0:16:14.000 about these prolate spheroids is if you align them in 0:16:14.040 --> 0:16:17.480 the direction of the flow of chocolate, you can pack 0:16:17.560 --> 0:16:20.320 more of them together. They have these elongated sides, and 0:16:20.360 --> 0:16:23.000 they will fit together much more snuggly. You can create 0:16:23.120 --> 0:16:28.440 chains of them and chocolate would flow much more readily. 0:16:28.480 --> 0:16:33.120 But how do you change the shape of those COCU particles. 0:16:33.520 --> 0:16:35.400 What is it that you could do to make them 0:16:35.400 --> 0:16:41.400 actually assume a different shape than their natural globular ball 0:16:41.560 --> 0:16:47.760 like shape. This is where electric fields come in. Uh, 0:16:47.840 --> 0:16:50.920 we're gonna talk about applying magnetic or electric fields to 0:16:50.960 --> 0:16:54.120 a fluid to changes viscosity. But first, this doesn't work 0:16:54.120 --> 0:16:58.400 with every fluid. Uh. Not every fluid reacts to electric 0:16:58.440 --> 0:17:00.760 fields and magnetic fields in a way that will alter 0:17:00.880 --> 0:17:04.119 its viscosity. But it does work in fluids that have 0:17:04.280 --> 0:17:08.880 certain non conducting or weakly conducting particles suspended in an 0:17:08.880 --> 0:17:13.920 electrically insulating fluid. Now we call this a special type 0:17:13.920 --> 0:17:20.280 of liquid, electro reological fluid. Electrohological fluids essentially means that 0:17:20.280 --> 0:17:23.800 when you apply an electric or magnetic field to such 0:17:23.800 --> 0:17:28.080 a fluid, it changes its viscosity. Sometimes we also call 0:17:28.160 --> 0:17:32.040 them smart fluids, But more about that in a bit now. Interestingly, 0:17:32.119 --> 0:17:35.719 the property was completely discovered by chance. There was an 0:17:35.760 --> 0:17:39.840 inventor named Willis Winslow who observed the effect in the 0:17:39.920 --> 0:17:45.360 nineteen forties, and he actually patented it in nineteen seven. Now, 0:17:45.400 --> 0:17:49.119 for this reason, we sometimes call this effect of changing 0:17:49.119 --> 0:17:54.200 an electroheological fluids viscosity the Winslow effect, and I'll mostly 0:17:54.240 --> 0:17:56.320 be using that term from here here on out, because 0:17:56.720 --> 0:17:58.280 there's only so many times I'm gonna be able to 0:17:58.280 --> 0:18:02.719 say electroheological before my mouth just decides to rebel against 0:18:02.720 --> 0:18:05.560 the rest of me and march out the door. And 0:18:05.640 --> 0:18:09.320 as entertaining as that would be kind of needed. Hey, 0:18:09.320 --> 0:18:11.600 it's modern day, Jonathan again. We're going to take another 0:18:11.680 --> 0:18:14.280 quick break to thank our sponsor and we'll be right back, 0:18:24.359 --> 0:18:27.919 all right. So, applying an electric or magnetic field to 0:18:27.960 --> 0:18:32.080 such a fluid changes that fluids viscosity within meliseconds like 0:18:32.119 --> 0:18:37.679 it's practically instantaneous, and if you remove the field, the 0:18:37.720 --> 0:18:41.000 particles in the fluid will snap back to their original shape, 0:18:41.040 --> 0:18:44.160 to the fluid's viscosity will return to what it normally 0:18:44.200 --> 0:18:47.919 would be. So the change isn't permanent. It only persists 0:18:48.080 --> 0:18:52.320 as long as the respective field persists, which is super 0:18:52.400 --> 0:18:56.000 cool because you can do these temporary changes that are 0:18:56.200 --> 0:18:59.399 really useful in specific situations and then have it go 0:18:59.480 --> 0:19:02.600 back to normal and it's like it never happened in 0:19:02.600 --> 0:19:06.080 the first place. But one thing to keep in mind 0:19:06.119 --> 0:19:09.119 is the direction of the electric or magnetic field is 0:19:09.359 --> 0:19:14.360 critically important when you want to make a particular effect. So, 0:19:14.440 --> 0:19:17.400 in the case of chocolate, if you apply the electric 0:19:17.440 --> 0:19:22.200 field perpendicular to the direction of flow, you will actually 0:19:22.359 --> 0:19:25.199 increase the viscosity of the chocolate. You will make it 0:19:25.359 --> 0:19:30.120 thicker more like a gel. Melted chocolate will turn into 0:19:30.160 --> 0:19:32.560 this kind of thick gel. It'll otherwise have all the 0:19:32.640 --> 0:19:38.800 same properties that had before, but the viscosity will increase dramatically. However, 0:19:39.080 --> 0:19:41.320 if you were to apply that electric field in the 0:19:41.400 --> 0:19:45.719 direction of the flow of chocolate, then you would decrease 0:19:45.760 --> 0:19:48.359 the viscosity of chocolate and it will flow more freely 0:19:48.480 --> 0:19:53.119 at that point. Now this makes some sense because imagine 0:19:53.119 --> 0:20:01.040 that you have these elongated ovals, these uh prolate sphere poids. Right. 0:20:01.960 --> 0:20:05.120 If you stand them vertically, then you could imagine them 0:20:05.160 --> 0:20:08.200 slipping through a pipe very easily. If you laid them 0:20:08.200 --> 0:20:13.320 out horizontally, you could imagine them ending up like like 0:20:13.480 --> 0:20:16.480 blocking a pipe easily, because it's like trying to fit 0:20:16.880 --> 0:20:19.800 a long stick through a narrow doorway. If you don't 0:20:19.800 --> 0:20:22.240 turn it the right way, you're just gonna hit against 0:20:22.240 --> 0:20:24.560 the door. This is making me think of my dog, Tibolt, 0:20:24.960 --> 0:20:28.120 who has done this on numerous occasions. He just he 0:20:28.160 --> 0:20:30.760 can't get it through his little doggy mind that he 0:20:30.800 --> 0:20:33.280 needs to turn the stick vertical in order to move 0:20:33.320 --> 0:20:36.720 it through a doorway. He just wants to charge ahead 0:20:36.760 --> 0:20:42.920 full steam with the stick horizontal. In many other ways. 0:20:42.920 --> 0:20:46.400 He's an intelligent dog, so we forgive him this lapse 0:20:46.560 --> 0:20:50.560 of judgment. Anyway, the chocolate on a molecular level is 0:20:50.640 --> 0:20:53.960 essentially the same thing. If you are applying this electric 0:20:54.000 --> 0:20:56.680 field perpendicular to the flow of chocolate, then you get 0:20:56.680 --> 0:21:00.960 this much thicker uh mixture. And then interesting side note, 0:21:01.640 --> 0:21:06.160 the electro real logical properties of chocolate aren't a new discovery, right. 0:21:06.440 --> 0:21:08.800 I mean, I covered this story for how stuff works 0:21:08.840 --> 0:21:14.240 now because there was a new application of this property 0:21:14.320 --> 0:21:17.359 with chocolate. But we actually knew that chocolate would react 0:21:17.400 --> 0:21:20.880 this way already, at least to the point of increasing 0:21:20.920 --> 0:21:25.880 the viscosity, because back in there was a Michigan State 0:21:25.960 --> 0:21:29.640 University grad student who observed the Winslow effect on chocolate. 0:21:29.680 --> 0:21:33.199 And his name is Dr Christopher R. Daubert, and as 0:21:33.240 --> 0:21:37.160 professor Dr James Steph worked with him. They both conducted 0:21:37.200 --> 0:21:41.080 experiments on liquid chocolate and observed the Winslow effect. Now, 0:21:41.119 --> 0:21:44.439 in that experiment, Daubert was again increasing the viscostity, not 0:21:44.720 --> 0:21:48.000 decreasing it. So he was turning chocolate into that thicker gel. 0:21:48.320 --> 0:21:51.560 That the liquid chocolate into thick gel. Uh. It wasn't 0:21:51.680 --> 0:21:55.080 until recently that we saw someone try and do the opposite. 0:21:56.000 --> 0:21:59.720 So that brings us to the Temple University experiment. So 0:22:00.320 --> 0:22:02.879 you have these researchers. They had worked on crude oil 0:22:03.200 --> 0:22:06.720 and decrease the viscosity of crude oil, which is a 0:22:06.800 --> 0:22:09.520 huge thing for the oil industry to be able to 0:22:10.119 --> 0:22:14.160 uh move oil more effectively without the fear of clogs 0:22:14.320 --> 0:22:18.399 or viscosity screwing up things that had been planned ahead 0:22:18.400 --> 0:22:21.480 of time. They wanted to see if they could in 0:22:21.520 --> 0:22:25.240 fact use a similar approach to have liquid chocolate move 0:22:25.320 --> 0:22:29.960 more smoothly through a system so that manufacturers could save 0:22:30.040 --> 0:22:33.360 money by not having to worry about cleaning up clogs 0:22:33.400 --> 0:22:38.040 and shutting down production for maintenance. So they had to 0:22:38.040 --> 0:22:41.919 test this hypothesis that an electric field directed in the 0:22:41.920 --> 0:22:46.000 flow of liquid chocolate would reduce viscosity. So they built 0:22:46.000 --> 0:22:50.760 a cool chocolate zapping gadget. It's not really a zapper, 0:22:51.600 --> 0:22:56.119 that's kind of a it's kind of not entirely accurate, 0:22:56.160 --> 0:22:58.960 but I like the idea of using electricity does zap 0:22:59.000 --> 0:23:02.800 chocolate and make it better. That's just a oversimplification of 0:23:02.840 --> 0:23:05.800 what happened, But that's okay. I'll I'll explain to you 0:23:06.040 --> 0:23:09.560 what was actually going on. They built this thing where 0:23:09.880 --> 0:23:12.919 it starts with a bit of a melting chamber. You 0:23:12.920 --> 0:23:15.840 can just think of it as like a a pot. 0:23:15.960 --> 0:23:18.280 It could even be a glass vial. Really, it could 0:23:18.320 --> 0:23:23.040 just be any little container that can hold chocolate. They 0:23:23.040 --> 0:23:26.480 put the chocolate in the container and they cover the container, 0:23:26.520 --> 0:23:31.200 sealing it shut. Uh. They added compressed nitrogen gas into 0:23:31.240 --> 0:23:34.280 the chamber simply really to to just increase the pressure 0:23:35.040 --> 0:23:38.000 inside the chamber itself. The chamber was heated so that 0:23:38.040 --> 0:23:41.000 you had chocolate melting into a liquid. There was a 0:23:41.000 --> 0:23:43.399 thermocouple in there to make sure that the temperature was 0:23:43.440 --> 0:23:46.920 correct so that the chocolate would not overheat or cool 0:23:47.000 --> 0:23:50.440 down so much that it becomes solid again. And then 0:23:50.480 --> 0:23:55.119 the base of this container was essentially a drain, so 0:23:55.680 --> 0:23:58.400 there's like a hole at the bottom of the container 0:23:58.480 --> 0:24:02.000 that liquid chocolate could float. Attached to that was a tube, 0:24:02.080 --> 0:24:04.679 and inside the tube they put a series of metal 0:24:05.480 --> 0:24:11.119 mesh screens and the screens were what generated the electric field. 0:24:11.119 --> 0:24:15.520 They had electricity running to those screens and creating electric 0:24:15.560 --> 0:24:18.480 field that way in the direction of the flow of chocolate, 0:24:19.040 --> 0:24:23.280 so the chocolate would end up flowing very smoothly through 0:24:23.400 --> 0:24:27.239 the tube and didn't have any issues. At the other end, 0:24:27.240 --> 0:24:31.640 they had another vessel container that the liquid chocolate would 0:24:31.680 --> 0:24:35.159 flow into, it would cool down solidify. So once that 0:24:35.240 --> 0:24:39.600 liquid chocolate flowed through into the collecting vessel UH and 0:24:39.680 --> 0:24:42.200 once it was free of the electric field, the cacao 0:24:42.359 --> 0:24:47.359 particles they went back to their original shape immediately. Again, 0:24:47.400 --> 0:24:50.000 they didn't have to transform or anything. It wasn't a 0:24:50.040 --> 0:24:54.679 gradual process. They moved back into those globe shapes that 0:24:54.720 --> 0:24:58.680 they typically are in, and the chocolate cooled and solidified 0:24:58.760 --> 0:25:03.280 and was to all intents and purposes, indistinguishable from the 0:25:03.320 --> 0:25:06.040 chocolate that was being fed through at the top, you know, 0:25:06.080 --> 0:25:10.480 at that top chamber. So they were able to reduce 0:25:10.560 --> 0:25:15.800 the viscosity of the flowing chocolate UH and to the 0:25:15.920 --> 0:25:18.359 to the point where it was no there were no 0:25:18.440 --> 0:25:21.719 issues of clogging. It was perfectly fine. So they were 0:25:21.720 --> 0:25:24.520 able to prove that their hypothesis was correct, that in fact, 0:25:25.000 --> 0:25:34.199 this electric field applied in this way would decrease chocolates viscosity, hooray. 0:25:34.520 --> 0:25:36.600 But there's more to it than that, So this experiment 0:25:36.640 --> 0:25:39.640 was not just a success. The researchers actually realized that 0:25:39.840 --> 0:25:43.360 it had a lot more implications than just having chocolate 0:25:43.400 --> 0:25:48.119 flow freely through a machine. Uh that Again, the reason 0:25:48.119 --> 0:25:51.359