WEBVTT - How Tech Could Make Better Chocolate 0:00:04.360 --> 0:00:07.680 Get in text technology with tech Stuff from how stuff 0:00:07.720 --> 0:00:14.560 Works dot com. Hey there, and welcome to tech Stuff. 0:00:14.600 --> 0:00:18.959 I'm your host, Jonathan Strickland. I'm flying solo today and 0:00:19.079 --> 0:00:21.799 I'm going to talk about something that I thought was 0:00:21.880 --> 0:00:25.120 really cool. I actually learned a lot in the process 0:00:25.640 --> 0:00:28.480 of looking into this. A few weeks ago, I covered 0:00:28.480 --> 0:00:32.000 a story for How stuff Works Now about a technique 0:00:32.120 --> 0:00:36.040 to make melted chocolate less viscous so that it flows 0:00:36.080 --> 0:00:39.920 more freely through manufacturing equipment. So a couple of things. 0:00:39.920 --> 0:00:42.760 First of all, How stuff Works Now, if you aren't familiar, 0:00:43.080 --> 0:00:46.960 is our more news oriented page, So if you go 0:00:47.000 --> 0:00:49.560 to now dot how stuff works dot com you can 0:00:49.600 --> 0:00:52.280 see it. We have a lot more stories that are 0:00:52.920 --> 0:00:56.760 reflective of things that are unfolding now, thus the name, 0:00:57.200 --> 0:00:59.480 and we also do video for that. There's also a 0:00:59.480 --> 0:01:03.440 podcast hosted by Lauren Vogelbaum. You can subscribe to that 0:01:03.520 --> 0:01:05.399 house Stuff Works Now. It's a summary of some of 0:01:05.440 --> 0:01:09.039 the stories that we cover each week. So if you're 0:01:09.080 --> 0:01:12.479 not familiar with that, go check it out. It's pretty awesome. Anyway, 0:01:13.000 --> 0:01:17.000 I did this story about chocolate and making sure you 0:01:17.000 --> 0:01:20.440 could reduce the viscosity of liquid chocolate so that it 0:01:20.480 --> 0:01:23.360 doesn't come up stuff, because one of the challenges of 0:01:23.400 --> 0:01:26.319 working with chocolate is making sure that it doesn't clog 0:01:26.400 --> 0:01:30.000 up the pipes like Augustus Gloop in Willy Wonka. So 0:01:30.440 --> 0:01:35.199 a consulting firm working on behalf of Mars Incorporated, which 0:01:35.240 --> 0:01:38.800 is giant candy company that makes a lot of different 0:01:38.880 --> 0:01:42.680 chocolate products. This consulting firm went to a group of 0:01:42.720 --> 0:01:46.160 physicists at Temple University, and physicist is one of those 0:01:46.160 --> 0:01:50.640 words I have difficulty pronouncing. I think I might just 0:01:50.640 --> 0:01:54.080 say scientists. Scientists at Temple University. Hey, and that's way better. 0:01:54.280 --> 0:01:57.320 And these guys have developed a method to make crude 0:01:57.320 --> 0:02:03.040 oil flow more easily through pipes using electric fields. So 0:02:03.360 --> 0:02:05.760 the question that the consulting firm had was could you 0:02:05.800 --> 0:02:08.359 do the same thing you did for crude oil for chocolate? 0:02:08.960 --> 0:02:12.720 And here's a spoiler alert, Yeah they could. But I 0:02:12.760 --> 0:02:15.280 want to talk more about what they did and how 0:02:15.320 --> 0:02:18.920 they did it because it's it's a really interesting, uh story. 0:02:19.880 --> 0:02:23.240 So I'm gonna go into a bit more detail about 0:02:23.280 --> 0:02:27.520 the physics and the technology behind the scientists solution for 0:02:27.520 --> 0:02:30.200 this problem. It's pretty cool, and a lot of it 0:02:30.240 --> 0:02:32.800 was stuff I had no idea about before I began 0:02:32.840 --> 0:02:34.959 to research the story. So today's episode is going to 0:02:35.040 --> 0:02:39.840 be about chocolate. It's gonna be about viscous fluids, about 0:02:39.880 --> 0:02:44.359 electro real logical fluids and how an electric field can 0:02:44.440 --> 0:02:49.120 change their fluid I properties, specifically viscosity. So yeah, this 0:02:49.160 --> 0:02:51.760 episode is gonna be science heavy, but there's also chocolate, 0:02:51.800 --> 0:02:55.480 so stick around. You know everyone loves chocolate. So let's 0:02:55.520 --> 0:03:00.880 get into the physics first. Now, fluid dynamics is be complicated, 0:03:01.080 --> 0:03:04.000 and also there's some stuff that's related to this that 0:03:04.520 --> 0:03:09.360 falls into the category of misinformation about viscosity. So I'll 0:03:09.400 --> 0:03:13.040 be talking a lot about not just the principles in general, 0:03:13.120 --> 0:03:17.840 but some specific uh myths that I would like to bust, 0:03:18.880 --> 0:03:21.600 as some of my former coworkers used to do on 0:03:21.600 --> 0:03:24.880 a regular basis. So, first of all, viscosity is a 0:03:24.919 --> 0:03:28.400 property of fluids or semi fluids, and it can be 0:03:28.440 --> 0:03:32.959 described as a fluids thickness or stickiness and its resistance 0:03:33.000 --> 0:03:38.120 to flowing due to internal friction. More accurately, viscosity is 0:03:38.120 --> 0:03:41.200 a measure of the resistance of a fluids deformation due 0:03:41.280 --> 0:03:46.320 to tensile or shear stress. Now, sheer stress is mechanical 0:03:46.360 --> 0:03:52.200 stress that's parallel to the surface of that substance. So, uh, 0:03:52.280 --> 0:03:56.920 you could think of sheer stress as it's not perpendicular. 0:03:56.960 --> 0:03:59.360 It's not like an impact, right, It's more of a 0:03:59.400 --> 0:04:02.760 tearing um ten style stress is a pulling stress rather 0:04:02.800 --> 0:04:06.360 than a compression stress. So again, instead of compressing stuff 0:04:07.040 --> 0:04:10.920 closer together, it's about pulling stuff further apart. And water 0:04:10.960 --> 0:04:16.560 has a pretty low viscosity. Honey has a very high viscosity. 0:04:16.640 --> 0:04:20.479 So we actually measure viscosity in units called poises p 0:04:20.720 --> 0:04:24.719 o I s e s. Water at room temperature twenty 0:04:24.760 --> 0:04:28.599 degrease celsius or so has a viscosity of zero point 0:04:28.960 --> 0:04:32.880 zero one poises or a center poise. In other words, 0:04:33.560 --> 0:04:36.679 a thick oil might have a viscosity of one point 0:04:36.800 --> 0:04:42.080 zero poise. Now we measure viscosity with a viscometer. I'm 0:04:42.080 --> 0:04:44.839 not making that up. It's actually the name of the 0:04:44.880 --> 0:04:49.760 tool used to measure a fluids viscosity. Now, typically we 0:04:49.839 --> 0:04:54.280 will call a liquid viscous if its viscosity is higher 0:04:54.320 --> 0:04:57.760 than that of waters, and if the viscosity is lower 0:04:57.880 --> 0:05:00.400 than that of waters, because water is not the least 0:05:00.560 --> 0:05:03.919 viscous material that we know of. If it has a 0:05:03.920 --> 0:05:06.839 lower of viscousy then water we call that fluid mobile. 0:05:08.000 --> 0:05:10.839 So some fluids are so viscous that they can actually 0:05:10.839 --> 0:05:13.680 seem to be a solid, and this leads us to 0:05:14.080 --> 0:05:17.359 that misinformation I was talking about. It's one of those 0:05:18.040 --> 0:05:22.000 things that I hear bandied about pretty well, not not 0:05:22.000 --> 0:05:24.359 not as frequently as it used to, but it's one 0:05:24.400 --> 0:05:27.920 of those miss understandings that gets passed around its fact 0:05:28.000 --> 0:05:30.760 every now and again. And that is the idea that 0:05:30.839 --> 0:05:34.119 glass is one of these fluids, that glass is actually 0:05:34.120 --> 0:05:37.880 a fluid that is um so viscous that it appears 0:05:37.920 --> 0:05:41.680 to be a solid, and that is not true. Glass 0:05:41.880 --> 0:05:46.039 is not a very, very viscous fluid. It's a little 0:05:46.080 --> 0:05:50.599 more complicated than that. Uh So, here's the basic idea. 0:05:50.720 --> 0:05:53.800 People have noticed that if they look at windows and 0:05:53.960 --> 0:05:58.560 very old buildings like medieval churches, they see that the 0:05:59.000 --> 0:06:03.440 base of the wind is thicker than the top of 0:06:03.440 --> 0:06:08.680 the window. And this has led some people to conclude, 0:06:09.000 --> 0:06:11.760 to jump to a conclusion that the reason why the 0:06:11.800 --> 0:06:15.000 base is thicker than the top is that glass, over 0:06:15.040 --> 0:06:19.800 the course of centuries has been flowing downward and that 0:06:19.960 --> 0:06:24.640 it's so slow that it's not detectable under normal situations. 0:06:24.960 --> 0:06:27.520 It's only over the course of centuries that you can 0:06:27.600 --> 0:06:30.839 see the difference. Uh. Here's the problem is that that's 0:06:30.880 --> 0:06:34.599 just not that's not the case. That's not true, it's 0:06:34.640 --> 0:06:40.400 not what's happening. Uh. If you look at the glass 0:06:40.520 --> 0:06:44.760 making approach in the Middle Ages, you'll see why there's 0:06:44.839 --> 0:06:47.919 a thicker part of the pane of glass. Glass was 0:06:48.160 --> 0:06:51.760 created generally speaking, in the Middle Ages through something called 0:06:51.960 --> 0:06:56.960 the crown glass process. It's pretty neat idea pretty neat 0:06:57.000 --> 0:07:01.680 way of making glass windows. Here's how it we're in general. First, 0:07:01.680 --> 0:07:05.200 you get your raw materials h to make glass, and 0:07:05.200 --> 0:07:08.440 in the Middle Ages that was essentially sand and potash, 0:07:08.520 --> 0:07:10.960 and you mix it together and you melt them in 0:07:11.040 --> 0:07:14.880 a very hot furnace. And then you would get a 0:07:14.920 --> 0:07:18.320 glass blower with a pipe and they would get roll 0:07:18.400 --> 0:07:20.880 out a lump of molten glass, put on the pipe, 0:07:21.640 --> 0:07:24.880 blow out the glass. So they expand the glass outward 0:07:24.960 --> 0:07:28.800 before flattening it, so they don't just you know, create 0:07:29.080 --> 0:07:31.960 a globe of glass, they actually flatten it back out. Then, 0:07:32.080 --> 0:07:35.280 with a flat glass which is still hot and still malleable, 0:07:35.320 --> 0:07:39.040 it hasn't cool to the point where it is really solidified. 0:07:39.440 --> 0:07:42.320 You would put that on a disk, a spinning disk, 0:07:42.400 --> 0:07:45.040 and the disk spins around to draw out the glass 0:07:45.080 --> 0:07:48.360 to flatten it further, sort of like how a pizza 0:07:48.400 --> 0:07:51.600 maker will toss and spend dough in the air in 0:07:51.760 --> 0:07:53.960 order to make that circular pizza. It's kind of similar 0:07:54.000 --> 0:07:58.360 to that. So the disk spins and the centripetal force, 0:07:59.080 --> 0:08:02.480 if you like, is pushing the glass outward toward the edges. 0:08:03.680 --> 0:08:07.320 So then once that's done, you would cut the glass 0:08:07.440 --> 0:08:11.840 into panes so that you could fit them in a window. Now, 0:08:12.000 --> 0:08:14.320 that would mean that when you would get anywhere close 0:08:14.360 --> 0:08:18.040 to where the edge of the glass was, the outer edge, 0:08:18.120 --> 0:08:19.760 because you put the glass on that disk and you 0:08:19.800 --> 0:08:23.400 spun it around, the outer edge was thicker than the 0:08:23.480 --> 0:08:26.760 rest of the glass, just because that's where the excess 0:08:26.840 --> 0:08:31.240 was accumulating as it was being uh pushed outward due 0:08:31.240 --> 0:08:35.959 to the spinning motion. So typically window makers would cut 0:08:36.000 --> 0:08:39.000 pains so that a thicker edge would only be on 0:08:39.000 --> 0:08:41.520 one side, and they put that side at the bottom 0:08:41.520 --> 0:08:44.800 at the base of the window, so glass didn't flow 0:08:44.960 --> 0:08:48.080 to the base. Over hundreds of years, it started out 0:08:48.200 --> 0:08:51.040 like like that. It was like that from the beginning. 0:08:51.600 --> 0:08:54.880 That being said, glass is a really interesting substance. It's 0:08:54.920 --> 0:08:59.160 what we would call an amorphous solid, so saying that 0:08:59.200 --> 0:09:02.760 it's a fluid or a liquid is not accurate. But 0:09:03.000 --> 0:09:06.800 it is an amorphous solid, which is a little hinky 0:09:06.960 --> 0:09:09.439 compared to other materials that you might be familiar with. 0:09:09.800 --> 0:09:15.439 So typically not everything, obviously metals and glass being exceptions, 0:09:15.440 --> 0:09:18.120 but a lot of solids have an ordered crystalline structure, 0:09:19.040 --> 0:09:21.600 so that means the molecules are organized in a pretty 0:09:21.600 --> 0:09:28.800 regular lattice. They form a nice repeating pattern that goes 0:09:28.840 --> 0:09:33.480 throughout the entire material. When you heat up this solid, 0:09:34.480 --> 0:09:37.080 those molecules start to shimmy and shake, some of the 0:09:37.080 --> 0:09:39.440 molecular bonds might start to break down a little bit, 0:09:40.240 --> 0:09:44.440 the bonds between one molecule and another, the essentially the 0:09:44.480 --> 0:09:47.760 crystalline order breaks down, and if you heat a solid 0:09:47.760 --> 0:09:50.880 beyond its melting point, the crystalline structure completely breaks down 0:09:50.880 --> 0:09:54.640 and molecules will begin to flow freely or as freely 0:09:54.679 --> 0:09:58.280 as the viscosity of that fluid allows, and there's a 0:09:58.400 --> 0:10:02.760 very clear delineation between the solid and liquid stages. You 0:10:02.760 --> 0:10:08.359 can see the difference molecularly from the way this substance 0:10:08.400 --> 0:10:11.360 looks when it's in solid form versus in liquid form, 0:10:11.400 --> 0:10:14.760 and we call that delineation that border between the two 0:10:14.920 --> 0:10:20.200 the first order phase transition. It's obvious when you look 0:10:20.240 --> 0:10:23.880 at it from a microscopic standpoint. I mean it's obvious 0:10:23.920 --> 0:10:27.880 from a macroscopic standpoint too, because a solid behaves one way, 0:10:27.880 --> 0:10:31.520 in a liquid behaves another way. Now, when you cool 0:10:31.559 --> 0:10:36.680 a liquid down, its viscosity tends to increase. If you 0:10:36.720 --> 0:10:40.880 introduce a nucleation site into the liquid, crystals can form 0:10:41.120 --> 0:10:44.360 and you get that nice solid structure again once you 0:10:44.400 --> 0:10:48.360 get down below what the melting point was. Uh, but 0:10:48.480 --> 0:10:53.439 glass doesn't do this. Glass doesn't form a crystalline structure. 0:10:54.360 --> 0:10:58.680 Glasses viscosity increases, so it does what other fluids do 0:10:58.720 --> 0:11:03.119 at that point. But since it doesn't crystallize, it solidifies 0:11:03.160 --> 0:11:06.839 in a different way. The molecules actually form an irregular arrangement, 0:11:07.480 --> 0:11:11.280 not that nice ordered structure that you see in other solids, 0:11:11.280 --> 0:11:14.520 but that a regular arrangement is still cohesive enough to 0:11:14.640 --> 0:11:20.000 maintain rigidity. So glass does become a solid, it's just 0:11:20.040 --> 0:11:25.000 not a crystalline solid. It's an amorphous solid. Now, there's 0:11:25.040 --> 0:11:27.959 no first order phase transition here. It's not like if 0:11:27.960 --> 0:11:30.520 you looked at the liquid form of glass and the 0:11:30.600 --> 0:11:33.520 solid form of glass, you would see a massive difference 0:11:33.679 --> 0:11:39.480 in the molecular structure. But there is a second order transition. Now. 0:11:39.480 --> 0:11:42.160 That transition is a little more subtle than first order 0:11:42.240 --> 0:11:46.800 transitions and evolves the thermal expansion and heat capacity of 0:11:46.840 --> 0:11:51.559 a material, So it wouldn't be as obvious to casual 0:11:51.679 --> 0:11:56.000 observation on a microscopic level, but there would still be 0:11:56.040 --> 0:12:01.280 differences with the thermodynamics of the material. Ill, so we 0:12:01.360 --> 0:12:03.800 still would say the glass is a solid not a liquid. 0:12:04.320 --> 0:12:06.920 All right, I'm done with glass now, I promise. I 0:12:06.920 --> 0:12:09.240 had to go on that little track just because it 0:12:09.240 --> 0:12:11.280 was related to the stuff I was talking about, and 0:12:11.640 --> 0:12:14.440 I get really irritated seeing that one myth passed around 0:12:14.440 --> 0:12:16.640 as fact. So now you know, if you ever go 0:12:16.760 --> 0:12:20.760 through a a tour and the tour guide says and 0:12:20.800 --> 0:12:23.240 the reason that the windows are thicker at the bottom 0:12:23.280 --> 0:12:25.720 is because glass flows over the course of hundreds of years, 0:12:26.040 --> 0:12:30.600 you can raise your hand and say, well, actually, and 0:12:30.640 --> 0:12:32.559 tell him Josh Clark sent you, because I don't want 0:12:32.559 --> 0:12:34.600 that kind of burden on me. I like being able 0:12:34.640 --> 0:12:39.640 to take tours anyway. Let's get back to Viscosty in general. So, 0:12:39.720 --> 0:12:43.199 like I said earlier, viscosty is due to internal friction 0:12:43.320 --> 0:12:46.360 of a liquid. And you might think that that sounds weird, 0:12:46.440 --> 0:12:49.040 like how can a liquid have friction inside of it? 0:12:49.320 --> 0:12:53.440 But we're talking about liquids specifically that have like molecules, 0:12:53.440 --> 0:12:56.040 and those molecules can have a tendency to resist getting 0:12:56.160 --> 0:13:00.080 by each other. So some molecules are more resistant you 0:13:01.160 --> 0:13:03.880 slipping by each other than others. Or a liquid could 0:13:03.920 --> 0:13:06.080 actually have particles that are suspended in it. It could 0:13:06.080 --> 0:13:09.800 be a suspension, which is different than just a pure liquid. 0:13:11.000 --> 0:13:15.280 But if it's a suspension, it's got particles suspended within 0:13:15.880 --> 0:13:19.720 the liquid at at some level of density, right, Like 0:13:19.880 --> 0:13:22.440 some maybe a pretty weak suspension where you don't have 0:13:22.440 --> 0:13:26.440 a whole lot, but others could have all a greater 0:13:27.080 --> 0:13:31.559 density of particles inside a suspension of fluid. Make chocolate bars, 0:13:31.640 --> 0:13:35.720 let's say, and you're laying out melted chocolate into the 0:13:35.760 --> 0:13:39.000 mold for the chocolate bars, uh, and it clogs up 0:13:39.120 --> 0:13:41.160 and you have to stop production and clean out the 0:13:41.200 --> 0:13:44.160 clog and get everything back up to temperature and start 0:13:44.200 --> 0:13:47.680 it all over again. It's time consuming and expensive when 0:13:47.720 --> 0:13:52.000 that happens. So one solution to preventing it from happening 0:13:52.160 --> 0:13:56.120 is dilute the cacao more so that those particles don't 0:13:56.120 --> 0:14:00.400 clump up as much because there there's a less dense 0:14:00.440 --> 0:14:05.760 cacao component in the fluid. That essentially means replacing cacao 0:14:05.920 --> 0:14:09.680 with something else, typically something that is less viscous, like 0:14:10.480 --> 0:14:14.600 that oil that fat. Essentially, so you usually add more 0:14:14.640 --> 0:14:18.319 fat to the recipe, so you get the more fat 0:14:18.360 --> 0:14:21.280 but less cacao. However, it ends up flowing better and 0:14:21.360 --> 0:14:26.240 creates the chocolate bars that you want without creating the clogs. 0:14:27.080 --> 0:14:29.840 But it's not necessarily the best product you could create. 0:14:29.920 --> 0:14:33.760 It's just the most convenient based upon the method of production. 0:14:35.520 --> 0:14:38.120 So that's where this alternative solution comes in. If you 0:14:38.120 --> 0:14:41.920 could change the shape of those cacao particles in the 0:14:41.920 --> 0:14:46.280 fluid so that they packed together more effectively, you would 0:14:46.280 --> 0:14:50.880 reduce that viscosity, that internal friction of the fluid. So 0:14:51.640 --> 0:14:54.760 imagine you've got one of those inflated rubber balls, like 0:14:54.760 --> 0:14:58.040 like a kickball or something. Now imagine that you're able 0:14:58.080 --> 0:15:02.840 to grab hold on either side of this ball and 0:15:02.920 --> 0:15:07.080 pull it outward so that you're elongating it. Now it 0:15:07.120 --> 0:15:11.400 would become a more of an oval shape, or as 0:15:11.480 --> 0:15:17.520 the researchers at Temple University called them, prolate spheroids. Now, 0:15:17.680 --> 0:15:20.800 the interesting thing about these prolate spheroids is if you 0:15:20.880 --> 0:15:23.720 align them in the direction of the flow of chocolate, 0:15:24.480 --> 0:15:26.600 you can pack more of them together. They have these 0:15:26.600 --> 0:15:29.920 elongated sides and they will fit together much more snuggly. 0:15:29.960 --> 0:15:34.920 You can create chains of them and chocolate would flow 0:15:35.040 --> 0:15:38.880 much more readily. But how do you change the shape 0:15:38.920 --> 0:15:42.000 of those cocu particles. What is it that you could 0:15:42.040 --> 0:15:46.000 do to make them actually assume a different shape than 0:15:46.000 --> 0:15:53.120 their natural globular ball like shape. This is where electric 0:15:53.240 --> 0:15:57.400 fields come in. Uh, we're gonna talk about applying magnetic 0:15:57.520 --> 0:16:00.680 or electric fields to a fluid to changes viscos. But first, 0:16:00.960 --> 0:16:04.680 this doesn't work with every fluid. Uh. Not every fluid 0:16:04.800 --> 0:16:07.640 reacts to electric fields and magnetic fields in a way 0:16:07.680 --> 0:16:10.880 that will alter its viscosity. But it does work in 0:16:10.960 --> 0:16:15.280 fluids that have certain non conducting or weakly conducting particles 0:16:15.320 --> 0:16:20.520 suspended in an electrically insulating fluid. Now, we call this 0:16:20.680 --> 0:16:27.000 a special type of liquid, electro reeological fluid. Electroheological fluids 0:16:27.120 --> 0:16:29.840 essentially means that when you apply an electric or magnetic 0:16:29.880 --> 0:16:35.120 field to such a fluid, it changes its viscosity. Sometimes 0:16:35.120 --> 0:16:37.200 we also call them smart fluids, but more about that 0:16:37.240 --> 0:16:41.600 in a bit now. Interestingly, the property was completely discovered 0:16:41.640 --> 0:16:46.280 by chance. There was an inventor named Willis Winslow who 0:16:46.280 --> 0:16:49.200 observed the effect in the nineteen forties, and he actually 0:16:49.280 --> 0:16:53.640 patented it in nineteen forty seven. Now, for this reason, 0:16:53.680 --> 0:16:58.160 we sometimes call this effect of changing an electroheological fluids 0:16:58.240 --> 0:17:02.160 viscosity the winds Low effect, And I'll mostly be using 0:17:02.200 --> 0:17:04.720 that term from here here on out, because there's only 0:17:04.760 --> 0:17:06.960 so many times I'm gonna be able to say electroheological 0:17:07.080 --> 0:17:10.640 before my mouth just decides to rebel against the rest 0:17:10.640 --> 0:17:13.920 of me and march out the door. And as entertaining 0:17:13.920 --> 0:17:24.400 as that would be, kind of needed. Alright, So, applying 0:17:24.440 --> 0:17:27.679 an electric or magnetic field to such a fluid changes 0:17:27.720 --> 0:17:33.560 that fluids viscosity within meloseconds like it's practically instantaneous. And 0:17:33.880 --> 0:17:36.720 if you remove the field, the particles in the fluid 0:17:36.720 --> 0:17:39.920 will snap back to their original shape, to the fluid's 0:17:40.000 --> 0:17:43.119 viscosity will return to what it normally would be. So 0:17:43.200 --> 0:17:46.920 the change isn't permanent. It only persists as long as 0:17:46.960 --> 0:17:51.159 the respective field persists, which is super cool because you 0:17:51.200 --> 0:17:55.320 can do these temporary changes that are really useful in 0:17:55.440 --> 0:17:58.240 specific situations and then have it go back to normal 0:17:58.680 --> 0:18:01.320 and it's like it never happened in the first place. 0:18:02.760 --> 0:18:04.879 But one thing to keep in mind is the direction 0:18:05.200 --> 0:18:09.560 of the electric or magnetic field is critically important when 0:18:09.760 --> 0:18:12.639 you want to make a particular effect. So, in the 0:18:12.640 --> 0:18:17.440 case of chocolate, if you apply the electric field perpendicular 0:18:17.480 --> 0:18:21.119 to the direction of flow, you will actually increase the 0:18:21.240 --> 0:18:24.200 viscosity of the chocolate. You will make it thicker, more 0:18:24.240 --> 0:18:28.480 like a gel. Melted chocolate will turn into this kind 0:18:28.480 --> 0:18:31.800 of thick gel. It'll otherwise have all the same properties 0:18:31.800 --> 0:18:36.800 that had before, but that viscosity will increase dramatically. However, 0:18:37.080 --> 0:18:39.320 if you were to apply that electric field in the 0:18:39.400 --> 0:18:43.760 direction of the flow of chocolate, then you would decrease 0:18:43.800 --> 0:18:46.399 the viscosity of chocolate and it will flow more freely 0:18:46.520 --> 0:18:51.119 at that point. Now this makes some sense because imagine 0:18:51.160 --> 0:18:59.080 that you have these elongated ovals, these uh prolate spheroids. Right, 0:19:00.040 --> 0:19:03.160 If you stand them vertically, then you can imagine them 0:19:03.160 --> 0:19:06.199 slipping through a pipe very easily. If you laid them 0:19:06.200 --> 0:19:11.360 out horizontally, you could imagine um ending up like like 0:19:11.480 --> 0:19:14.480 blocking a pipe easily, because it's like trying to fit 0:19:14.920 --> 0:19:17.800 a long stick through a narrow doorway. If you don't 0:19:17.840 --> 0:19:20.240 turn it the right way, you're just gonna hit against 0:19:20.240 --> 0:19:22.640 the door. This is making me think of my dog Tiboalt, 0:19:22.960 --> 0:19:26.120 who has done this on numerous occasions. He just he 0:19:26.200 --> 0:19:29.080 can't get it through his little doggy mind. They needs 0:19:29.119 --> 0:19:31.439 to turn the stick vertical in order to move it 0:19:31.480 --> 0:19:35.000 through a doorway. He just wants to charge ahead full 0:19:35.119 --> 0:19:41.120 steam with the stick horizontal. In many other ways, He's 0:19:41.119 --> 0:19:46.560 an intelligent dog, so we forgive him this lapse of judgment. Anyway, 0:19:46.840 --> 0:19:49.720 the chocolate on a molecular level is essentially the same thing. 0:19:50.119 --> 0:19:53.320 If you are applying this electric field perpendicular to the 0:19:53.320 --> 0:19:57.640 flow of chocolate, then you get this much thicker uh mixture. 0:19:57.680 --> 0:20:01.920 And an interesting side note, the electro reeological properties of 0:20:02.000 --> 0:20:05.240 chocolate aren't a new discovery, right. I mean, I covered 0:20:05.280 --> 0:20:09.359 this story for how stuff works now because there was 0:20:09.640 --> 0:20:13.639 a new application of this property with chocolate. But we 0:20:13.680 --> 0:20:16.639 actually knew that chocolate would react this way already, at 0:20:16.680 --> 0:20:20.480 least to the point of increasing the viscosity, because back 0:20:20.520 --> 0:20:25.720 in there was a Michigan State University grad student who 0:20:25.760 --> 0:20:28.320 observed the Winslow effect on chocolate, and his name is 0:20:28.440 --> 0:20:33.080 Dr Christopher R. Daubert, and as professor Dr James Steph 0:20:33.440 --> 0:20:36.880 worked with him. They both conducted experiments on liquid chocolate 0:20:36.880 --> 0:20:40.400 and observed the Winslow effect. Now, in that experiment, Daubert 0:20:40.440 --> 0:20:44.040 was again increasing the viscosity, not decreasing it, so he 0:20:44.080 --> 0:20:47.000 was turning chocolate into that thicker gel. That the liquid 0:20:47.080 --> 0:20:50.760 chocolate into thick gel. Uh. It wasn't until recently that 0:20:50.840 --> 0:20:54.320 we saw someone try and do the opposite. So that 0:20:54.359 --> 0:20:58.600 brings us to the Temple University experiment. So you had 0:20:58.640 --> 0:21:02.240 these researchers. They had worked on crude oil and decrease 0:21:02.320 --> 0:21:05.320 the viscosity of crude oil, which is a huge thing 0:21:05.440 --> 0:21:08.800 for the oil industry to be able to uh move 0:21:08.880 --> 0:21:14.000 oil more effectively without the fear of clogs or viscosity 0:21:14.160 --> 0:21:16.800 screwing up things that had been planned ahead of time. 0:21:18.280 --> 0:21:20.119 They wanted to see if they could in fact use 0:21:20.160 --> 0:21:24.080 a similar approach to have liquid chocolate move more smoothly 0:21:24.160 --> 0:21:29.200 through a system so that manufacturers could save money by 0:21:29.320 --> 0:21:32.080 not having to worry about cleaning up clogs and shutting 0:21:32.080 --> 0:21:36.399 down production for maintenance. So They had to test this 0:21:36.480 --> 0:21:40.399 hypothesis that an electric field directed in the flow of 0:21:40.560 --> 0:21:44.480 liquid chocolate would reduce viscosity. So they built a cool 0:21:44.640 --> 0:21:50.120 chocolate zapping gadget. That's not really a zapper, that's kind 0:21:50.119 --> 0:21:54.399 of a it's kind of not entirely accurate, but I 0:21:54.480 --> 0:21:57.480 like the idea of using electricity does zap chocolate and 0:21:57.520 --> 0:22:01.320 make it better. That's just a over simplification of what happened, 0:22:01.359 --> 0:22:04.440 But that's okay. I'll I'll explain to you what was 0:22:04.480 --> 0:22:08.359 actually going on. They built this thing where it starts 0:22:08.359 --> 0:22:11.199 with a bit of a melting chamber. You can just 0:22:11.200 --> 0:22:14.280 think of it as like a a pot. It could 0:22:14.280 --> 0:22:16.640 even be a glass vial. Really, it could just be 0:22:16.720 --> 0:22:21.320 any little container that can hold chocolate. They put the 0:22:21.359 --> 0:22:24.919 chocolate in the container and they cover the container, sealing 0:22:24.920 --> 0:22:29.320 it shut. Uh. They added compressed nitrogen gas into the 0:22:29.400 --> 0:22:33.480 chamber simply really to to just increase the pressure inside 0:22:33.480 --> 0:22:36.159 the chamber itself. The chamber was heated so that you 0:22:36.240 --> 0:22:39.639 had chocolate melting into a liquid. There was a thermocouple 0:22:39.680 --> 0:22:41.800 in there to make sure that the temperature was correct 0:22:42.480 --> 0:22:45.240 so that the chocolate would not overheat or cool down 0:22:45.280 --> 0:22:48.600 so much that it becomes solid again. And then the 0:22:48.680 --> 0:22:54.280 base of this container was essentially a drain, so there's 0:22:54.320 --> 0:22:56.600 like a hole at the bottom of the container that 0:22:56.720 --> 0:22:59.960 liquid chocolate could flow through. Attached to that was a tube, 0:23:00.119 --> 0:23:02.719 and inside the tube they put a series of metal 0:23:03.480 --> 0:23:09.119 mesh screens, and the screens were what generated the electric field. 0:23:09.160 --> 0:23:13.560 They had electricity running to those screens and creating electric 0:23:13.600 --> 0:23:16.520 field that way in the direction of the flow of chocolate, 0:23:17.080 --> 0:23:21.280 so the chocolate would end up flowing very smoothly through 0:23:21.400 --> 0:23:25.239 the tube and didn't have any issues. At the other end, 0:23:25.280 --> 0:23:29.680 they had another vessel container that the liquid chocolate would 0:23:29.680 --> 0:23:33.199 flow into, it would cool down solidify. So once that 0:23:33.280 --> 0:23:37.600 liquid chocolate flowed through into the collecting vessel, uh and 0:23:37.680 --> 0:23:40.200 once it was free of the electric field, the cacao 0:23:40.359 --> 0:23:45.359 particles they went back to their original shape immediately. Again. 0:23:45.400 --> 0:23:48.040 They didn't have to transform or anything. It wasn't a 0:23:48.080 --> 0:23:52.600 gradual process. They whoop moved back into those globe shapes 0:23:52.640 --> 0:23:55.960 that they typically are in, and the chocolate cooled and 0:23:56.000 --> 0:24:01.240 solidified and was, to all intents and purposes, indistinguishable from 0:24:01.240 --> 0:24:03.399 the chocolate that was being fed through at the top, 0:24:03.880 --> 0:24:07.359 you know, at that top chamber. So they were able 0:24:07.440 --> 0:24:13.359 to reduce the viscosity of the flowing chocolate uh and 0:24:13.560 --> 0:24:16.160 to the to the point where it was no there 0:24:16.160 --> 0:24:19.600 were no issues of clogging. It's perfectly fine. So they 0:24:19.600 --> 0:24:22.040 were able to prove that their hypothesis was correct, that 0:24:22.080 --> 0:24:27.040 in fact, this electric field applied in this way would 0:24:27.080 --> 0:24:33.600 decrease chocolates viscosity. Hooray. But there's more to it than that, 0:24:33.760 --> 0:24:36.440 So this experiment was not just a success. The researchers 0:24:36.480 --> 0:24:40.400 actually realized that it had a lot more implications than 0:24:40.480 --> 0:24:45.679 just having chocolate flow freely through a machine. Uh. That Again, 0:24:45.720 --> 0:24:48.560 the reason why chocolate has such a relatively high fat 0:24:48.640 --> 0:24:53.240 content is to create that oily fluid to reduce viscosity, 0:24:53.320 --> 0:24:57.920 to have the cacao particles suspended within it at a 0:24:58.000 --> 0:25:01.840 density that's low enough so you're not likely to clog 0:25:01.920 --> 0:25:05.640 up the machines. But if you use this approach, if 0:25:05.680 --> 0:25:09.960 you use the electric fields to reduce the viscosity, you 0:25:10.000 --> 0:25:14.480 don't need as much oil or fat in your chocolate content. 0:25:14.600 --> 0:25:17.960 You could actually start with a recipe that has less 0:25:18.080 --> 0:25:22.000 fat in it, and the electric fields would take care 0:25:22.080 --> 0:25:25.520 of the viscosity problem, so you don't have to have 0:25:25.640 --> 0:25:27.639 as much fat there. That also means you can have 0:25:27.720 --> 0:25:31.439 more cacao in your mixture. It could be a higher 0:25:31.600 --> 0:25:36.080 proportion of the overall recipe. So they found that they 0:25:36.080 --> 0:25:39.320 could reduce the fat content in certain types of chocolate 0:25:39.920 --> 0:25:42.840 by as much as twenty percent and still have no 0:25:42.960 --> 0:25:47.640