1 00:00:03,040 --> 00:00:07,040 Speaker 1: Welcome to Stuff to Blow Your Mind production of iHeartRadio. 2 00:00:12,720 --> 00:00:15,680 Speaker 2: Hey, welcome to Stuff to Blow Your Mind. My name 3 00:00:15,720 --> 00:00:16,800 Speaker 2: is Robert Lamb. 4 00:00:16,760 --> 00:00:19,520 Speaker 3: And I'm Joe McCormick, and today we are coming back 5 00:00:19,600 --> 00:00:23,720 Speaker 3: with part two in our series on stickiness. This is 6 00:00:23,760 --> 00:00:26,920 Speaker 3: a topic I got interested in after feeding my ten 7 00:00:27,000 --> 00:00:31,479 Speaker 3: month old various fruits and fruit based smoothies and stuff, 8 00:00:32,080 --> 00:00:36,480 Speaker 3: and noticing the way that a kind of stealth stickiness 9 00:00:36,479 --> 00:00:41,200 Speaker 3: can easily migrate outside of the direct vicinity of eating 10 00:00:41,600 --> 00:00:46,040 Speaker 3: and contaminate surfaces beyond. There's a kind of stickiness fallout 11 00:00:46,080 --> 00:00:49,800 Speaker 3: effect after the initial meltdown. Rob I think you said 12 00:00:49,880 --> 00:00:51,919 Speaker 3: last time, you've had similar experiences. 13 00:00:52,159 --> 00:00:55,280 Speaker 2: Oh, yes, and I'm still finding sticky spots in the house, 14 00:00:55,360 --> 00:00:57,760 Speaker 2: you know. Now here's a question about your daughter. Has 15 00:00:57,800 --> 00:01:01,960 Speaker 2: she used the stickiness to scale walls yet? 16 00:01:02,360 --> 00:01:05,039 Speaker 3: No, she has not figured this out yet, but she's 17 00:01:05,080 --> 00:01:08,240 Speaker 3: crafty and I think she could be getting there very soon. 18 00:01:10,280 --> 00:01:11,679 Speaker 2: More on wall climbing in a bit. 19 00:01:12,319 --> 00:01:15,640 Speaker 3: Yeah, the creature will not be contained. But so in 20 00:01:15,680 --> 00:01:20,120 Speaker 3: the last episode we started off talking about difficulties and 21 00:01:20,319 --> 00:01:24,280 Speaker 3: even defining stickiness rigorously. This is one of those subjects 22 00:01:24,319 --> 00:01:28,440 Speaker 3: where I expected there to be a pretty simple, straightforward, 23 00:01:28,720 --> 00:01:33,240 Speaker 3: well understood physics or chemistry answer to what makes things sticky? 24 00:01:33,520 --> 00:01:36,080 Speaker 3: And it turns out no, the answer is super complex 25 00:01:36,200 --> 00:01:39,920 Speaker 3: and in some ways not fully understood, and we'll be 26 00:01:39,959 --> 00:01:43,040 Speaker 3: talking more about that some at the beginning of today's episode. 27 00:01:43,040 --> 00:01:45,440 Speaker 3: But in the last episode we also discussed one of 28 00:01:45,480 --> 00:01:50,600 Speaker 3: the most glorious of sticky foods, glutinous rice aka sticky 29 00:01:50,680 --> 00:01:56,040 Speaker 3: rice aka sweet rice, the unstoppable amylopectin avalanche. 30 00:01:56,680 --> 00:01:58,960 Speaker 2: That's right, I hope if nothing else, we inspired everyone 31 00:01:58,960 --> 00:02:02,080 Speaker 2: out there to seek out some sticky rice or sticky 32 00:02:02,200 --> 00:02:06,520 Speaker 2: rice derived food products in wake of listening. 33 00:02:07,200 --> 00:02:09,200 Speaker 3: Did you have some sticky rice over the weekend after 34 00:02:09,240 --> 00:02:11,040 Speaker 3: we did the episode? 35 00:02:11,880 --> 00:02:14,400 Speaker 2: I had some mochi, and I really I think it 36 00:02:14,560 --> 00:02:17,720 Speaker 2: enhanced my enjoyment of the mochi, and I'm looking forward 37 00:02:17,760 --> 00:02:21,720 Speaker 2: to having sticky rice the next opportunity I get nice. 38 00:02:22,440 --> 00:02:25,960 Speaker 3: Well, today, we wanted to further explore the concept of stickiness, 39 00:02:25,960 --> 00:02:28,840 Speaker 3: and one place I wanted to start was with a 40 00:02:29,200 --> 00:02:31,680 Speaker 3: chapter in a book that I've been reading. It's a 41 00:02:31,760 --> 00:02:35,560 Speaker 3: very good book called Sticky The Secret Science of Surfaces 42 00:02:35,960 --> 00:02:40,040 Speaker 3: by Laurie Winkless. This is a popular science book from Bloomsbury, 43 00:02:40,240 --> 00:02:43,480 Speaker 3: twenty twenty three. So this is just recently published. And 44 00:02:43,960 --> 00:02:46,639 Speaker 3: this book is not just about stickiness. It's about all 45 00:02:46,639 --> 00:02:50,560 Speaker 3: different kinds of surface interaction, so it covers slipperiness and 46 00:02:50,600 --> 00:02:53,560 Speaker 3: friction and all that stuff too. But there is a 47 00:02:53,600 --> 00:02:57,360 Speaker 3: great chapter early in the book about stickiness. And this 48 00:02:57,400 --> 00:03:00,160 Speaker 3: book is full of interesting stuff about the world that 49 00:03:00,320 --> 00:03:03,840 Speaker 3: I never thought of before. For example, in this chapter 50 00:03:04,000 --> 00:03:09,320 Speaker 3: on stickiness or adhesion, Winkless is talking about how oil 51 00:03:09,440 --> 00:03:13,320 Speaker 3: based paints are made. Typically, so an oil based paint 52 00:03:13,400 --> 00:03:15,960 Speaker 3: is usually going to be a solid pigment of some kind, 53 00:03:16,040 --> 00:03:19,760 Speaker 3: little colored particles that are suspended in a liquid medium 54 00:03:20,400 --> 00:03:23,440 Speaker 3: that might be something like linseed oil. And then it'll 55 00:03:23,480 --> 00:03:25,800 Speaker 3: also have additives in it that will be things like 56 00:03:25,880 --> 00:03:29,240 Speaker 3: stabilizers to help thicken the mixture and disperse the pigment 57 00:03:29,240 --> 00:03:32,560 Speaker 3: particles evenly. But the thing that really caught my attention 58 00:03:32,639 --> 00:03:35,840 Speaker 3: is she gets to an interesting fact, which is when 59 00:03:35,920 --> 00:03:39,520 Speaker 3: you use an oil based paint. Maybe you're painting a 60 00:03:39,560 --> 00:03:42,040 Speaker 3: painting on a canvas with some oil based paint. What 61 00:03:42,080 --> 00:03:44,320 Speaker 3: do you do when you're done painting? You let it dry. 62 00:03:44,480 --> 00:03:47,960 Speaker 3: We say that it dries, but actually the paint does 63 00:03:48,040 --> 00:03:52,680 Speaker 3: not dry drying would mean that it loses moisture through evaporation, 64 00:03:53,160 --> 00:03:56,760 Speaker 3: but moisture does not leave the oil based paint. Instead, 65 00:03:56,800 --> 00:04:01,000 Speaker 3: what oil based paints do is polymerize. This is sometimes 66 00:04:01,000 --> 00:04:05,000 Speaker 3: called curing. So instead of losing water molecules to the 67 00:04:05,080 --> 00:04:10,520 Speaker 3: air through evaporation, these paints steal oxygen from the air 68 00:04:10,720 --> 00:04:15,040 Speaker 3: and use that oxygen to form bonds between molecules, which 69 00:04:15,040 --> 00:04:18,000 Speaker 3: allows the paint to harden into a solid film and 70 00:04:18,120 --> 00:04:21,599 Speaker 3: form these layers of hard solid films. And because oil 71 00:04:21,600 --> 00:04:25,360 Speaker 3: based paints remove oxygen from the air rather than drying 72 00:04:25,400 --> 00:04:30,360 Speaker 3: by losing moisture, they actually get heavier, not lighter, as 73 00:04:30,400 --> 00:04:33,760 Speaker 3: they cure. So Winkles says that paints based on linseed 74 00:04:33,760 --> 00:04:37,360 Speaker 3: oil can sometimes increase their weight by over fifteen percent 75 00:04:37,560 --> 00:04:42,159 Speaker 3: during curing, so a painting would be heavier after it's 76 00:04:42,279 --> 00:04:45,480 Speaker 3: dry than when it was wet if you use one 77 00:04:45,480 --> 00:04:48,200 Speaker 3: of these paints. Now you can contrast this to water 78 00:04:48,279 --> 00:04:51,920 Speaker 3: based paints, which actually do dry by losing moisture, and 79 00:04:51,960 --> 00:04:55,080 Speaker 3: these will leave behind only the solid pigments held in 80 00:04:55,120 --> 00:04:58,559 Speaker 3: place by binder compounds. So when you buy a can 81 00:04:58,600 --> 00:05:01,600 Speaker 3: of water based paint, most of the volume of that 82 00:05:01,680 --> 00:05:04,080 Speaker 3: can is not actually going to end up on your wall. 83 00:05:04,120 --> 00:05:08,320 Speaker 3: It will instead evaporate. And in illustrating this, she writes, 84 00:05:08,400 --> 00:05:14,279 Speaker 3: quote Colin Gooch, technical director of paint manufacturer Racine, told 85 00:05:14,279 --> 00:05:17,000 Speaker 3: me that a four liter can of high quality waterborne 86 00:05:17,080 --> 00:05:20,560 Speaker 3: paint might contain just over one point five leaders of 87 00:05:20,720 --> 00:05:24,760 Speaker 3: volume solids. That's what actually forms the film that stays 88 00:05:24,760 --> 00:05:27,200 Speaker 3: on the surface. The job of the other two point 89 00:05:27,279 --> 00:05:30,520 Speaker 3: five leaders is to keep those solids dispersed. It allows 90 00:05:30,600 --> 00:05:33,240 Speaker 3: us to carry the pigment from the can to the wall. 91 00:05:33,720 --> 00:05:36,719 Speaker 2: This is crazy. I'd never thought about this before either. 92 00:05:36,839 --> 00:05:41,000 Speaker 2: It makes me wonder if I were using oil based 93 00:05:41,000 --> 00:05:45,360 Speaker 2: paints in painting minis instead of the acrylic paints that 94 00:05:45,440 --> 00:05:49,000 Speaker 2: I use. Like what the difference would be like all 95 00:05:49,040 --> 00:05:50,800 Speaker 2: the you know, sort of the fine art of the thing. 96 00:05:50,880 --> 00:05:53,840 Speaker 2: Do you have to factor that in to how much 97 00:05:53,839 --> 00:05:56,040 Speaker 2: paint you're applying. I don't know. I'd love to hear 98 00:05:56,080 --> 00:05:59,000 Speaker 2: it doesn't out there with experience painting anything, you know, 99 00:05:59,080 --> 00:06:00,719 Speaker 2: minis or canvas or houses. 100 00:06:01,400 --> 00:06:05,719 Speaker 3: Yeah, the book doesn't get into how the material the 101 00:06:05,760 --> 00:06:09,640 Speaker 3: differences and the materials affect the craft itself, but I 102 00:06:09,760 --> 00:06:10,840 Speaker 3: expect they probably do. 103 00:06:11,279 --> 00:06:11,479 Speaker 2: Yeah. 104 00:06:12,000 --> 00:06:14,560 Speaker 3: But anyway, coming to the more general topic in the 105 00:06:14,600 --> 00:06:17,520 Speaker 3: same chapter of What Stickiness Is, I wanted to talk 106 00:06:17,560 --> 00:06:21,840 Speaker 3: about some of the things that Winkless explains here. And 107 00:06:22,120 --> 00:06:26,480 Speaker 3: there are two very important concepts for stickiness. One is 108 00:06:26,600 --> 00:06:31,760 Speaker 3: adhesion and the other is cohesion. Adhesion is the attraction 109 00:06:32,000 --> 00:06:36,800 Speaker 3: between two different materials, and it's defined usually by the 110 00:06:37,080 --> 00:06:39,719 Speaker 3: work or the effort that it takes to separate the 111 00:06:39,760 --> 00:06:43,839 Speaker 3: two materials. And then cohesion is the attraction of a 112 00:06:43,920 --> 00:06:47,960 Speaker 3: material to itself. How the molecules of the substance, how 113 00:06:48,000 --> 00:06:51,640 Speaker 3: well they stay stuck together to each other. Now, to 114 00:06:51,680 --> 00:06:56,080 Speaker 3: discuss the different physical models of adhesion, how two different 115 00:06:56,320 --> 00:07:01,560 Speaker 3: substances stick together, Winkless starts by imagining a hypothetical interface 116 00:07:01,640 --> 00:07:04,960 Speaker 3: between two different things. So you imagine a drop of 117 00:07:05,080 --> 00:07:08,680 Speaker 3: some kind of liquid, some kind of adhesive liquid, sitting 118 00:07:08,720 --> 00:07:11,920 Speaker 3: on top of a clean, flat block of solid material. 119 00:07:12,040 --> 00:07:14,240 Speaker 3: So you can think of a drop of water sitting 120 00:07:14,280 --> 00:07:16,040 Speaker 3: on a piece of wood, or a piece of metal, 121 00:07:16,400 --> 00:07:18,920 Speaker 3: or a drop of whatever of glue. You know you're 122 00:07:18,920 --> 00:07:22,000 Speaker 3: going to be measuring how well this thing adheres. And 123 00:07:22,640 --> 00:07:26,920 Speaker 3: coming back to the level of uncertainty that I've found 124 00:07:26,960 --> 00:07:31,200 Speaker 3: surprising in this subject, she writes that the general consensus 125 00:07:31,320 --> 00:07:34,880 Speaker 3: is that there are quote three or four ways that 126 00:07:34,920 --> 00:07:37,040 Speaker 3: these materials could interact. 127 00:07:37,240 --> 00:07:40,200 Speaker 2: Yeah, this is a familiar thread, it seems that one 128 00:07:40,320 --> 00:07:45,120 Speaker 2: finds when you start researching stickiness is that, Yeah, we 129 00:07:45,160 --> 00:07:48,880 Speaker 2: don't necessarily know On one l hand, we might not 130 00:07:48,920 --> 00:07:52,440 Speaker 2: necessarily know like the one thing that is making something stick, 131 00:07:52,480 --> 00:07:56,560 Speaker 2: and it may more honestly be various things, and there's 132 00:07:56,600 --> 00:08:00,320 Speaker 2: disagreement on to what extent each thing is contributed to 133 00:08:01,040 --> 00:08:01,800 Speaker 2: the stickiness. 134 00:08:02,400 --> 00:08:06,120 Speaker 3: That's right. So the first one of these models of 135 00:08:06,160 --> 00:08:11,040 Speaker 3: interaction for adherents is chemical adherents, and this means there's 136 00:08:11,040 --> 00:08:16,000 Speaker 3: an actual chemical reaction. There are molecular bonds between the 137 00:08:16,040 --> 00:08:19,000 Speaker 3: adhesive and the surface, so some kind of reaction has 138 00:08:19,040 --> 00:08:23,440 Speaker 3: taken place, resulting in essentially a new compound where they 139 00:08:23,520 --> 00:08:27,800 Speaker 3: meet and winkless. Here uses the example of paint. Quote. 140 00:08:28,160 --> 00:08:31,000 Speaker 3: In paint, this sort of adhesion is enabled by the 141 00:08:31,160 --> 00:08:34,800 Speaker 3: binder molecules that surround the pigment particles. So the pigment 142 00:08:34,800 --> 00:08:38,120 Speaker 3: particles are the little solid particles that give the paint 143 00:08:38,160 --> 00:08:41,079 Speaker 3: its color, and then they have these binder molecules that 144 00:08:41,920 --> 00:08:45,640 Speaker 3: surround those pigment particles and help stick them to the surface. 145 00:08:46,200 --> 00:08:49,160 Speaker 3: She says, quote they react with molecules on the surface 146 00:08:49,240 --> 00:08:53,840 Speaker 3: sharing and borrowing electrons, effectively forming a new compound at 147 00:08:53,880 --> 00:08:59,280 Speaker 3: the interface. So this is actual chemical interaction here. Second 148 00:08:59,320 --> 00:09:04,800 Speaker 3: model of action is mechanical adhesion. Here there's not a 149 00:09:04,880 --> 00:09:08,520 Speaker 3: chemical reaction going on between the adhesive and the surface. Instead, 150 00:09:08,880 --> 00:09:12,640 Speaker 3: Winkless uses the analogy that one sticks to the other, 151 00:09:13,280 --> 00:09:16,160 Speaker 3: like the way a rock climber clings to the surface 152 00:09:16,200 --> 00:09:19,800 Speaker 3: of a cliff by like sticking fingers and toes into 153 00:09:19,920 --> 00:09:23,960 Speaker 3: cracks and crevices in the rock. So the drop of 154 00:09:23,960 --> 00:09:26,480 Speaker 3: the adhesive wants to stick to itself. Of course, it 155 00:09:26,520 --> 00:09:30,000 Speaker 3: wants to stay intact, much like the rock climber's body 156 00:09:30,080 --> 00:09:33,560 Speaker 3: wants to stay intact and stick to itself. And parts 157 00:09:33,679 --> 00:09:38,520 Speaker 3: of this adhesive are jammed into recesses in the surface 158 00:09:38,720 --> 00:09:42,640 Speaker 3: of the solid material. Now you might think, well, okay, 159 00:09:42,679 --> 00:09:45,559 Speaker 3: but what about smooth surfaces. And the fact is that 160 00:09:45,600 --> 00:09:49,000 Speaker 3: basically all surfaces, even if they're pretty smooth as far 161 00:09:49,000 --> 00:09:51,719 Speaker 3: as you can tell at the macro scale, they've got 162 00:09:51,800 --> 00:09:54,800 Speaker 3: lots of little irregularities when you zoom in. If you 163 00:09:54,800 --> 00:09:58,360 Speaker 3: get a high sensitivity microscope, you can zoom in and 164 00:09:58,400 --> 00:10:02,679 Speaker 3: see mountains and ravines the microscale, most surfaces you will 165 00:10:02,720 --> 00:10:07,000 Speaker 3: find in the real world are like this. Third model 166 00:10:07,040 --> 00:10:12,280 Speaker 3: of adhesion is diffusion. This typically happens when the solid 167 00:10:12,320 --> 00:10:16,120 Speaker 3: material in the scenario is a polymer, for example, rubber 168 00:10:16,520 --> 00:10:20,000 Speaker 3: or cellulose or nylon. There are lots of different kinds 169 00:10:20,000 --> 00:10:24,080 Speaker 3: of polymers in the world, and structurally, polymers are long 170 00:10:24,400 --> 00:10:29,120 Speaker 3: molecules with a repeating structure, sort of like the links 171 00:10:29,120 --> 00:10:33,200 Speaker 3: in a chain. In diffusion, these long chains can sort 172 00:10:33,200 --> 00:10:38,440 Speaker 3: of intermingle and tangle with several nanometers of material on 173 00:10:38,559 --> 00:10:42,000 Speaker 3: the other side, on the other object or the other substance, 174 00:10:42,320 --> 00:10:46,199 Speaker 3: even though they're not reacting chemically. And this might be 175 00:10:46,200 --> 00:10:49,040 Speaker 3: a kind of crude analogy, but for a rough picture, 176 00:10:49,120 --> 00:10:52,280 Speaker 3: just sort of like imagine surfaces that have a bunch 177 00:10:52,320 --> 00:10:54,880 Speaker 3: of chains and ropes and strings at the edge of 178 00:10:54,920 --> 00:10:59,400 Speaker 3: them getting tangled up with the edge of the other object. Now, 179 00:10:59,440 --> 00:11:02,280 Speaker 3: remember you said there were three or four. This last 180 00:11:02,280 --> 00:11:05,640 Speaker 3: one seems more debatable, but Winkless notes that the adhesive 181 00:11:05,679 --> 00:11:10,680 Speaker 3: product manufacturer three M also identifies a fourth possible type 182 00:11:10,720 --> 00:11:15,760 Speaker 3: of adhesion, and this is electrostatic. Sometimes, if you are 183 00:11:15,880 --> 00:11:19,680 Speaker 3: about to attach a strip of adhesive tape to a 184 00:11:19,679 --> 00:11:22,920 Speaker 3: piece of paper, you will see the paper actually kind 185 00:11:22,960 --> 00:11:26,040 Speaker 3: of move through the air like it's reaching out toward 186 00:11:26,160 --> 00:11:28,280 Speaker 3: the tape. You know, they want to you know, it 187 00:11:28,360 --> 00:11:31,920 Speaker 3: wants to be found, like the one ring, and it's 188 00:11:32,280 --> 00:11:34,440 Speaker 3: kind of like it's being attracted by a magnet because 189 00:11:34,520 --> 00:11:37,559 Speaker 3: it's sort of is This is because the tape accumulates 190 00:11:37,960 --> 00:11:40,600 Speaker 3: charged particles as you peel it off of the roll, 191 00:11:41,120 --> 00:11:44,920 Speaker 3: and there is attraction due to static electricity there same 192 00:11:44,960 --> 00:11:47,679 Speaker 3: reason you know, you get static electricity on a balloon 193 00:11:47,840 --> 00:11:50,320 Speaker 3: or something and then it lifts your hair off of 194 00:11:50,360 --> 00:11:51,079 Speaker 3: your head. 195 00:11:51,320 --> 00:11:54,200 Speaker 2: Yeah, or occasionally in that scenario where there's some little 196 00:11:54,240 --> 00:11:57,560 Speaker 2: bit of plastic garbage or packaging that you are trying 197 00:11:57,600 --> 00:12:00,000 Speaker 2: to throw away and it just clings to your hand 198 00:12:00,160 --> 00:12:02,600 Speaker 2: and you can't fling it away, even though there's obviously 199 00:12:02,640 --> 00:12:05,880 Speaker 2: nothing sticky on your hands. You weren't just messing around 200 00:12:05,920 --> 00:12:09,120 Speaker 2: with glue, you haven't, you know, you've washed your hands. 201 00:12:09,320 --> 00:12:11,240 Speaker 2: But yeah, it's sticking to you because of the static. 202 00:12:11,480 --> 00:12:14,320 Speaker 3: So that is a real force. But Winkles says that 203 00:12:14,400 --> 00:12:17,160 Speaker 3: she doubts whether this should really be considered a true 204 00:12:17,280 --> 00:12:22,200 Speaker 3: adhesive force that like meaningfully sticks objects together, because while 205 00:12:22,200 --> 00:12:25,200 Speaker 3: it might cause an initial attraction, this is not really 206 00:12:25,280 --> 00:12:28,120 Speaker 3: what would like hold a you know, an adhesive tape 207 00:12:28,160 --> 00:12:31,520 Speaker 3: firmly to the paper, what prevents it from peeling off? 208 00:12:32,480 --> 00:12:35,920 Speaker 3: But it's important to note she says that no single 209 00:12:35,960 --> 00:12:40,679 Speaker 3: one of these forces fully explains stickiness, and she writes quote, 210 00:12:40,720 --> 00:12:45,120 Speaker 3: for any given adhesive product, it's almost impossible to determine 211 00:12:45,160 --> 00:12:48,439 Speaker 3: exactly which model or models might be operating. 212 00:12:50,240 --> 00:12:53,120 Speaker 2: That's that's interesting just even to think of in terms 213 00:12:53,200 --> 00:12:55,560 Speaker 2: of hobbyists, you know, because there's so many different types 214 00:12:55,600 --> 00:12:57,640 Speaker 2: of glues, and you get into any given hobby, you 215 00:12:57,679 --> 00:12:59,680 Speaker 2: might think, well, all clues are the same, but of 216 00:12:59,679 --> 00:13:03,600 Speaker 2: course they're most certainly not. You know, some expand some don't. 217 00:13:04,320 --> 00:13:09,199 Speaker 2: You know, some are more about like essentially melting one 218 00:13:09,200 --> 00:13:14,079 Speaker 2: bit of plastic into another. So yeah, it's I guess 219 00:13:14,120 --> 00:13:16,560 Speaker 2: the thing we keep running up against is like everything 220 00:13:16,640 --> 00:13:20,120 Speaker 2: involving stickiness. There's like this level of language you have 221 00:13:20,160 --> 00:13:22,319 Speaker 2: to get past, as well as sort of the level 222 00:13:22,360 --> 00:13:25,480 Speaker 2: of human perspective, you know, like we're just we're just 223 00:13:25,520 --> 00:13:27,679 Speaker 2: too big. We're not on the same level where all 224 00:13:27,720 --> 00:13:29,160 Speaker 2: of this is actually taking place. 225 00:13:29,520 --> 00:13:31,960 Speaker 3: Yes, And I think also when we think about it, 226 00:13:31,960 --> 00:13:35,280 Speaker 3: we're usually thinking, we're trying to think too simply, we 227 00:13:35,320 --> 00:13:37,440 Speaker 3: think about it in one direction. We think, like why 228 00:13:37,440 --> 00:13:40,480 Speaker 3: does X stick to why? Like why does duct tape 229 00:13:40,559 --> 00:13:43,520 Speaker 3: stick to the wall, And we think that there would 230 00:13:43,559 --> 00:13:46,560 Speaker 3: be one answer for that. There is one cause. But 231 00:13:46,720 --> 00:13:50,000 Speaker 3: it might be better to think about stickiness as an 232 00:13:50,000 --> 00:13:54,520 Speaker 3: emergent system that relies on many different things interacting, rather 233 00:13:54,600 --> 00:14:08,559 Speaker 3: than a property one thing does to another. Now, remember 234 00:14:08,600 --> 00:14:11,800 Speaker 3: all of everything I've been saying so far was about adhesion, 235 00:14:11,880 --> 00:14:15,720 Speaker 3: how two different materials cling to each other. Another important 236 00:14:15,760 --> 00:14:19,720 Speaker 3: factor in stickiness is cohesion, the tendency of a material 237 00:14:19,760 --> 00:14:23,640 Speaker 3: to stick to itself. So in order for a sticky 238 00:14:23,680 --> 00:14:26,240 Speaker 3: material like paint to work the way that it's supposed to, 239 00:14:26,600 --> 00:14:29,520 Speaker 3: it has to be both adhesive meaning it sticks to 240 00:14:29,560 --> 00:14:33,400 Speaker 3: the wall, and cohesive, meaning it sticks to itself. If 241 00:14:33,440 --> 00:14:35,960 Speaker 3: either of these properties fails, then it's not going to 242 00:14:36,000 --> 00:14:40,000 Speaker 3: be good paint. Another interesting factor that Winkless discusses in 243 00:14:40,040 --> 00:14:43,880 Speaker 3: this chapter is what's known as surface energy. So when 244 00:14:43,920 --> 00:14:45,560 Speaker 3: you come back to that image of you put a 245 00:14:45,640 --> 00:14:48,760 Speaker 3: drop of some kind of liquids, some adhesive liquids, sitting 246 00:14:48,840 --> 00:14:52,720 Speaker 3: on a flat, solid surface, the nature of the solid 247 00:14:52,760 --> 00:14:57,120 Speaker 3: material that the liquid is sitting on also influences how 248 00:14:57,200 --> 00:15:00,880 Speaker 3: well the adhesive sticks and one of the carearacteristics that 249 00:15:01,040 --> 00:15:06,640 Speaker 3: matters is that solid material's surface energy. So technically, the 250 00:15:06,680 --> 00:15:10,560 Speaker 3: surface energy of a material is the extra energy present 251 00:15:10,680 --> 00:15:14,200 Speaker 3: at the outside of a solid mass compared to the 252 00:15:14,360 --> 00:15:18,320 Speaker 3: energy present inside the mass. And this extra energy is 253 00:15:18,320 --> 00:15:21,800 Speaker 3: there because of imbalances of molecular bonds on the surface 254 00:15:21,920 --> 00:15:25,680 Speaker 3: of the object. But for a more intuitive understanding of 255 00:15:25,720 --> 00:15:29,160 Speaker 3: surface energy, you can think about it basically as equivalent 256 00:15:29,200 --> 00:15:33,640 Speaker 3: to wet ability. Usually, you can predict how well and 257 00:15:33,760 --> 00:15:37,120 Speaker 3: adhesive will stick to a surface by looking at how 258 00:15:37,200 --> 00:15:41,280 Speaker 3: easily the surface gets wet, how well it attracts water. 259 00:15:41,800 --> 00:15:45,520 Speaker 3: And a common test used to measure surface energy is 260 00:15:45,560 --> 00:15:49,040 Speaker 3: to look at what's known as the contact angle of 261 00:15:49,120 --> 00:15:51,800 Speaker 3: a drop of water on the surface of the material. 262 00:15:52,200 --> 00:15:54,880 Speaker 3: That might sound kind of abstract, but it's actually when 263 00:15:54,880 --> 00:15:58,360 Speaker 3: you see it illustrated, it's pretty easy to understand. So 264 00:15:59,000 --> 00:16:01,840 Speaker 3: imagine you put a drop of water flat on a 265 00:16:01,880 --> 00:16:05,800 Speaker 3: solid surface, and it can be it could be wood, metal, cardboard, whatever. 266 00:16:06,800 --> 00:16:10,120 Speaker 3: Watch what the water does. Does it spread out and 267 00:16:10,240 --> 00:16:14,080 Speaker 3: form a wide, flat disk or kind of a lens shape, 268 00:16:14,880 --> 00:16:17,320 Speaker 3: or does it stand up a little bit taller and 269 00:16:17,360 --> 00:16:21,040 Speaker 3: form kind of a flat bottomed hemisphere or does it 270 00:16:21,080 --> 00:16:23,680 Speaker 3: sit way high up in almost kind of a full 271 00:16:23,760 --> 00:16:26,920 Speaker 3: sphere or bead shape. The first one I talked about, 272 00:16:26,920 --> 00:16:30,840 Speaker 3: the wide flat lens of water is what or has 273 00:16:30,880 --> 00:16:34,280 Speaker 3: what's known as a low contact angle. If you measure 274 00:16:34,320 --> 00:16:37,960 Speaker 3: the angle between the water droplet and the flat surface, 275 00:16:38,080 --> 00:16:41,400 Speaker 3: it's going to be pretty narrow, well below ninety degrees. 276 00:16:41,880 --> 00:16:45,960 Speaker 3: A low contact angle means that this surface likes water. 277 00:16:46,080 --> 00:16:49,400 Speaker 3: It attracts water, and it has a high surface energy. 278 00:16:49,520 --> 00:16:51,160 Speaker 3: And you can kind of see that because the water's 279 00:16:51,200 --> 00:16:55,240 Speaker 3: like spreading out. It's the water wants to touch the surface. Meanwhile, 280 00:16:55,440 --> 00:16:58,480 Speaker 3: the bead of water that sits almost like a sphere 281 00:16:58,600 --> 00:17:01,280 Speaker 3: or a ball up on the surface has a very 282 00:17:01,360 --> 00:17:05,719 Speaker 3: high contact angle. It minimizes contact with the solid, and 283 00:17:05,760 --> 00:17:08,800 Speaker 3: this indicates that the solid has a low surface energy, 284 00:17:09,000 --> 00:17:12,080 Speaker 3: and it's a substance that wants to fight off wetness. 285 00:17:12,119 --> 00:17:14,359 Speaker 3: It wicks away the moisture. So you might think of 286 00:17:14,480 --> 00:17:17,639 Speaker 3: like a think of like a waxy leaf, you know, 287 00:17:17,680 --> 00:17:20,000 Speaker 3: where that you see water hidden and it just rolls 288 00:17:20,119 --> 00:17:22,840 Speaker 3: right away. It's like what you know, it almost seems 289 00:17:22,840 --> 00:17:27,440 Speaker 3: like it's impossible for it to get wet. In most cases, 290 00:17:28,160 --> 00:17:34,359 Speaker 3: this quality the surface energy correlates with stickiness. Surfaces with 291 00:17:34,440 --> 00:17:37,760 Speaker 3: a high energy that attract water then and form that 292 00:17:37,800 --> 00:17:42,360 Speaker 3: flat disc shape are also usually easier to stick things too, 293 00:17:43,040 --> 00:17:46,359 Speaker 3: and Winkless writes, this is kind of interesting. Surface energy 294 00:17:46,480 --> 00:17:50,240 Speaker 3: also tends to correlate with the coefficient of friction. It's 295 00:17:50,280 --> 00:17:52,280 Speaker 3: not a hard and fast rule by any means, but 296 00:17:52,280 --> 00:17:55,640 Speaker 3: if a material has low surface energy, if it's slippery 297 00:17:55,680 --> 00:18:00,600 Speaker 3: to liquids, it is often also low friction slippery to solids. 298 00:18:01,280 --> 00:18:03,960 Speaker 3: So I thought that's kind of interesting. As she says, 299 00:18:03,800 --> 00:18:07,639 Speaker 3: it doesn't hold in every single case, but generally, the 300 00:18:07,720 --> 00:18:11,639 Speaker 3: easier it is to kind of like slide smoothly over 301 00:18:11,680 --> 00:18:15,760 Speaker 3: something without rubbing or sticking to it, also that surface 302 00:18:15,800 --> 00:18:18,359 Speaker 3: that you're sliding over is going to be harder to 303 00:18:18,560 --> 00:18:22,360 Speaker 3: like stick sticky things to. But also on the subject 304 00:18:22,359 --> 00:18:24,840 Speaker 3: of surface energy, this coming back to what we were 305 00:18:24,840 --> 00:18:27,240 Speaker 3: talking about earlier. I was really not expecting a book 306 00:18:27,280 --> 00:18:31,359 Speaker 3: chapter about the science of stickiness and adhesion to contain 307 00:18:31,480 --> 00:18:35,480 Speaker 3: much controversy. But you know, again, this just feels like 308 00:18:35,520 --> 00:18:38,080 Speaker 3: one of those topics that you would find already pretty 309 00:18:38,160 --> 00:18:41,720 Speaker 3: much settled and more just kind of standardized textbook explanations, 310 00:18:41,760 --> 00:18:44,879 Speaker 3: like we all know how this works, but once again, 311 00:18:44,880 --> 00:18:47,520 Speaker 3: this topic still does contain a lot of mystery and 312 00:18:47,600 --> 00:18:51,159 Speaker 3: room for disagreement. And one of those areas of disagreement 313 00:18:51,480 --> 00:18:55,760 Speaker 3: that Winkless documents is disagreements between materials scientists and chemists 314 00:18:56,280 --> 00:19:01,240 Speaker 3: about how important surface energy actually is when you're making 315 00:19:01,440 --> 00:19:05,399 Speaker 3: things like glues or adhesives that are supposed to hold 316 00:19:05,520 --> 00:19:10,440 Speaker 3: together to different solid materials. So she cites a professor 317 00:19:10,520 --> 00:19:12,720 Speaker 3: named Stephen Abbott, who is a fellow with the Royal 318 00:19:12,760 --> 00:19:16,080 Speaker 3: Society of Chemistry, who argues that, and these are abbots 319 00:19:16,119 --> 00:19:20,480 Speaker 3: words quote, surface energy is undoubtedly useful for paint, but 320 00:19:20,600 --> 00:19:24,879 Speaker 3: for practical adhesive systems where we're actually sticking stuff together, 321 00:19:24,960 --> 00:19:28,640 Speaker 3: it's basically irrelevant, thousands of times too small to give 322 00:19:28,720 --> 00:19:31,520 Speaker 3: us what we need, and yet people are obsessed with it. 323 00:19:32,240 --> 00:19:35,400 Speaker 3: So he seems almost mildly annoyed by this. Maybe I'm 324 00:19:35,440 --> 00:19:38,080 Speaker 3: reading too much tone into that, but either way, I 325 00:19:38,080 --> 00:19:41,359 Speaker 3: thought it was fascinating that this topic is has so 326 00:19:41,400 --> 00:19:44,840 Speaker 3: many more questions within it than I realized, Like and 327 00:19:44,920 --> 00:19:48,520 Speaker 3: the fact that we have lots of adhesive products that 328 00:19:48,600 --> 00:19:51,040 Speaker 3: work pretty well, Like you know, they're companies that make 329 00:19:51,400 --> 00:19:54,600 Speaker 3: tapes and glues and sticky notes and all kinds of things. 330 00:19:54,600 --> 00:19:58,359 Speaker 3: They stick to one another pretty effectively. And we know 331 00:19:58,680 --> 00:20:02,640 Speaker 3: at least some and may all of the underlying mechanisms 332 00:20:02,680 --> 00:20:06,560 Speaker 3: by which these by which these products work, and they 333 00:20:06,560 --> 00:20:09,440 Speaker 3: do work, and yet you still can't say in every 334 00:20:09,520 --> 00:20:14,199 Speaker 3: case which mechanism or mechanisms are making the difference. And 335 00:20:14,240 --> 00:20:17,280 Speaker 3: part of this is because stickiness is not merely a 336 00:20:17,320 --> 00:20:20,920 Speaker 3: property of one material, but, as we were saying, an 337 00:20:20,960 --> 00:20:26,280 Speaker 3: interaction between two or more materials and the conditions under 338 00:20:26,400 --> 00:20:30,359 Speaker 3: which they interact. And at the later on in this chapter, 339 00:20:30,720 --> 00:20:36,040 Speaker 3: Winkless quotes the same researcher, Stephen Abbott, saying, quote, adhesion 340 00:20:36,160 --> 00:20:39,600 Speaker 3: is a property of the system. It's not a property 341 00:20:39,640 --> 00:20:43,800 Speaker 3: of like the individual substance. But it's all these things 342 00:20:43,880 --> 00:20:50,399 Speaker 3: interacting together. They have adhesive behavior as a whole or not. 343 00:20:51,720 --> 00:20:54,000 Speaker 2: Yeah, I think that's key. That's key to keep in mind, 344 00:20:54,040 --> 00:20:57,560 Speaker 2: and it's it also factors into what I'm about to 345 00:20:57,560 --> 00:20:59,800 Speaker 2: discuss here in a minute, because originally the plan was 346 00:21:00,119 --> 00:21:02,200 Speaker 2: that I thought, well, we'll roll through a few different 347 00:21:02,200 --> 00:21:05,080 Speaker 2: animal examples of which ones are sticky and why are 348 00:21:05,160 --> 00:21:10,199 Speaker 2: they sticky? Foolishly thinking again that we must have have 349 00:21:10,320 --> 00:21:13,199 Speaker 2: this settled. It must be settled how this particular animal 350 00:21:13,240 --> 00:21:16,400 Speaker 2: sticks to a wall. And we do know a lot 351 00:21:17,200 --> 00:21:20,560 Speaker 2: about this topic, but it's maybe not as perfect of 352 00:21:20,680 --> 00:21:24,720 Speaker 2: knowledge as one might expect. And and and I do 353 00:21:24,840 --> 00:21:27,160 Speaker 2: have to, you know, to admit that. Of course, this 354 00:21:27,280 --> 00:21:29,000 Speaker 2: is the case with plenty of plenty of other things 355 00:21:29,040 --> 00:21:31,760 Speaker 2: about animals that we are even very familiar with. I mean, 356 00:21:32,040 --> 00:21:34,600 Speaker 2: even a house cat has its secrets. There are things 357 00:21:34,640 --> 00:21:38,760 Speaker 2: about house cat behavior that we have varying ideas about 358 00:21:38,800 --> 00:21:43,119 Speaker 2: and we haven't completely worked out. But yeah, with stickiness, 359 00:21:43,160 --> 00:21:45,639 Speaker 2: it's easy just to again to completely take it for granted, 360 00:21:45,680 --> 00:21:48,320 Speaker 2: to approach it from our you know, look at it 361 00:21:48,359 --> 00:21:53,560 Speaker 2: through the fog of our scale and our language and think, oh, yeah, 362 00:21:53,640 --> 00:21:56,280 Speaker 2: well it just sticks right. It's like, you know, it's 363 00:21:56,320 --> 00:21:57,320 Speaker 2: it's like a suction cup. 364 00:21:57,520 --> 00:22:00,520 Speaker 3: Well, speaking of suction cups, that brings up an interesting thing, 365 00:22:00,560 --> 00:22:03,520 Speaker 3: which is that on the macroscopic scale, you can get 366 00:22:03,800 --> 00:22:06,760 Speaker 3: stickying forces that have nothing to do with any of 367 00:22:06,760 --> 00:22:08,639 Speaker 3: the stuff we've been talking about so far, because we 368 00:22:08,640 --> 00:22:12,560 Speaker 3: were just talking about like surfaces sticking to one another 369 00:22:12,720 --> 00:22:15,600 Speaker 3: due to properties of the surfaces. But in the case 370 00:22:15,640 --> 00:22:17,440 Speaker 3: of a suction cup, like if you want to stick 371 00:22:17,440 --> 00:22:19,760 Speaker 3: a suction cup to a window and climb a skyscraper 372 00:22:19,840 --> 00:22:22,640 Speaker 3: like Tom Cruise in one of those Mission Impossible movies. 373 00:22:23,000 --> 00:22:25,679 Speaker 3: That's a totally different mechanism. What's going on there is 374 00:22:25,720 --> 00:22:29,879 Speaker 3: the suction cup. By evacuating the air from the space 375 00:22:29,920 --> 00:22:33,040 Speaker 3: between the cup and the smooth surface, you are creating 376 00:22:33,080 --> 00:22:37,399 Speaker 3: a low pressure area inside, which allows the atmosphere to 377 00:22:37,520 --> 00:22:40,119 Speaker 3: press on the outside of the cup and hold it 378 00:22:40,200 --> 00:22:42,959 Speaker 3: against the wall. So when Tom Cruise is doing that, 379 00:22:43,000 --> 00:22:46,359 Speaker 3: what he's really doing is letting the atmosphere, the weight 380 00:22:46,400 --> 00:22:49,479 Speaker 3: of the atmosphere press his handholds against the building. 381 00:22:50,119 --> 00:22:53,200 Speaker 2: Is Tom Cruise still climbing up buildings with the suction cups? 382 00:22:53,200 --> 00:22:55,240 Speaker 2: Is that still happening in the current movies. 383 00:22:55,920 --> 00:22:57,879 Speaker 3: I think he was in the most recent one of 384 00:22:57,920 --> 00:22:58,600 Speaker 3: those I saw. 385 00:22:58,760 --> 00:23:00,760 Speaker 2: Maybe that's the way. I can't remember did that, And 386 00:23:00,880 --> 00:23:03,000 Speaker 2: I think I only saw the first Mission Impossible movie, 387 00:23:03,080 --> 00:23:05,720 Speaker 2: And if you told me that he used suction cups, 388 00:23:05,720 --> 00:23:08,119 Speaker 2: I would just assume, Well, I guess he probably used them. 389 00:23:08,440 --> 00:23:10,560 Speaker 2: It seems like the sort of thing he would do. 390 00:23:10,680 --> 00:23:13,679 Speaker 3: I think in the first one he uses magnets, because 391 00:23:13,680 --> 00:23:17,480 Speaker 3: that's when he's on the top of that train, you know, Oh, no, 392 00:23:18,040 --> 00:23:21,160 Speaker 3: John Voight, and they're fighting for a helicopter on top 393 00:23:21,200 --> 00:23:21,680 Speaker 3: of a train. 394 00:23:22,080 --> 00:23:25,440 Speaker 2: I remember John Voight, And don't they lower him into lasers? 395 00:23:25,560 --> 00:23:27,440 Speaker 2: Is that the movie with lowering endo lasers. 396 00:23:27,359 --> 00:23:28,520 Speaker 3: Lower him in the lasers. 397 00:23:28,760 --> 00:23:31,920 Speaker 2: Yeah, like room full of like laser trip wires and 398 00:23:31,920 --> 00:23:33,800 Speaker 2: they have to like it comes down from. 399 00:23:33,640 --> 00:23:37,040 Speaker 3: The cel Oh I don't know, Yeah, yeah, yeah. The 400 00:23:37,080 --> 00:23:38,960 Speaker 3: first one is where they put Tom Cruise on a 401 00:23:39,080 --> 00:23:41,959 Speaker 3: rope and they lower him down through out of an 402 00:23:42,000 --> 00:23:45,240 Speaker 3: air vent into a room that the floor is lava. 403 00:23:45,320 --> 00:23:47,480 Speaker 3: You can't touch the floor or the alarms will golf. 404 00:23:47,680 --> 00:23:50,920 Speaker 3: And that was so he could steal the knock list, 405 00:23:51,119 --> 00:23:55,840 Speaker 3: you know, the knocklst I had VHS to the first Yeah. 406 00:23:56,240 --> 00:23:59,800 Speaker 2: I guess I only saw it once. Then. Yeah. I 407 00:24:00,240 --> 00:24:01,800 Speaker 2: don't have any strong feelings about it one one or 408 00:24:01,800 --> 00:24:04,440 Speaker 2: the other, but I mean I admire, I admire the 409 00:24:04,960 --> 00:24:06,520 Speaker 2: commitment to amazing stunts. 410 00:24:07,000 --> 00:24:10,200 Speaker 3: Apart from like the coronal mass ejection of star power 411 00:24:10,200 --> 00:24:12,639 Speaker 3: that is Tom Cruise. Most of those movies have a 412 00:24:12,680 --> 00:24:15,280 Speaker 3: pretty cool supporting cast. Oh you know the first one 413 00:24:15,359 --> 00:24:19,360 Speaker 3: it had Ving Raims and John Renau. 414 00:24:19,840 --> 00:24:23,040 Speaker 2: Yeah, yeah, I believe you're right. Yeah, yeah, strong casts 415 00:24:23,520 --> 00:24:27,560 Speaker 2: all right. Well, speaking of star power, and speaking of 416 00:24:27,640 --> 00:24:31,440 Speaker 2: daring stunts. The main creature we're going to talk about 417 00:24:31,440 --> 00:24:35,040 Speaker 2: here today is going to be the gecko. I'm also 418 00:24:35,040 --> 00:24:36,720 Speaker 2: going to get a little bit into Spider Man later, 419 00:24:36,720 --> 00:24:39,560 Speaker 2: but Spider Man's not real. The gecko is real, and 420 00:24:39,600 --> 00:24:42,840 Speaker 2: the gecko is quite amazing, one of the most famous 421 00:24:42,880 --> 00:24:46,840 Speaker 2: sticky animals of all, though to be clear, not all 422 00:24:46,920 --> 00:24:52,120 Speaker 2: geckos have this ability. For instance, the oft domesticated leopard gecko. 423 00:24:52,840 --> 00:24:54,960 Speaker 2: There's actually one of these living in my house. It's 424 00:24:55,320 --> 00:24:59,200 Speaker 2: my son's pet, is a ground dwelling lizard and does 425 00:24:59,240 --> 00:25:02,120 Speaker 2: not have this ability. But geckos are found on every 426 00:25:02,160 --> 00:25:08,639 Speaker 2: continent except Antarctica various species of the infraorder Gekota. Of these, 427 00:25:08,840 --> 00:25:13,760 Speaker 2: some sixty percent have adhesive toepads that enable climbing, although 428 00:25:13,760 --> 00:25:16,840 Speaker 2: this ability has apparently been lost and gained many times 429 00:25:16,840 --> 00:25:17,640 Speaker 2: over their evolution. 430 00:25:18,160 --> 00:25:21,080 Speaker 3: Now, when you hear that a gecko has adhesive toepads, 431 00:25:21,880 --> 00:25:23,720 Speaker 3: first of all, that might make sense because you've probably 432 00:25:23,720 --> 00:25:27,119 Speaker 3: seen a gecko climbing up a flat surface like a 433 00:25:27,200 --> 00:25:30,760 Speaker 3: you know, a window pane or a sliding door, or 434 00:25:30,960 --> 00:25:33,240 Speaker 3: the wall of a building or a tree trunk, or 435 00:25:33,240 --> 00:25:36,399 Speaker 3: even climbing on the underside of things. Again, much like 436 00:25:36,440 --> 00:25:40,080 Speaker 3: tom cruise kind of doing overhang free climbs, going around 437 00:25:40,080 --> 00:25:43,000 Speaker 3: on the ceiling. It is pretty amazing what they're able 438 00:25:43,040 --> 00:25:46,520 Speaker 3: to do, and across the range of surfaces across which 439 00:25:46,520 --> 00:25:49,919 Speaker 3: they're able to do it. So you might just assume, okay, 440 00:25:49,960 --> 00:25:53,000 Speaker 3: well they got you know, toes that feel like glue. 441 00:25:53,040 --> 00:25:54,520 Speaker 3: Like if you were to go put your hand on 442 00:25:54,560 --> 00:25:57,960 Speaker 3: a gecko's toe, it would be a gross, sticky you know, 443 00:25:57,960 --> 00:26:00,399 Speaker 3: almost kind of like a like a sugar seer or 444 00:26:00,400 --> 00:26:03,919 Speaker 3: something like that. But no, no, that's not the case. 445 00:26:04,400 --> 00:26:06,760 Speaker 3: If you go and look at the toe and feel 446 00:26:06,840 --> 00:26:09,640 Speaker 3: the toe of a gecko, the kind that has these 447 00:26:09,680 --> 00:26:13,200 Speaker 3: amazing climbing powers and clinging powers, it feels totally smooth. 448 00:26:13,359 --> 00:26:16,639 Speaker 3: It is not covered in a sticky adhesive like the 449 00:26:16,640 --> 00:26:17,639 Speaker 3: back of duct tape. 450 00:26:18,000 --> 00:26:20,679 Speaker 2: Yeah, it's one of the things that's long fascinated us 451 00:26:20,720 --> 00:26:23,960 Speaker 2: about the gecko. And again, geckos are widespread, so they've 452 00:26:24,000 --> 00:26:26,840 Speaker 2: been there. They're around for great thinkers of different ages 453 00:26:26,880 --> 00:26:32,080 Speaker 2: to potentially ponder them, and in fact, Aristotle mentions them 454 00:26:32,600 --> 00:26:36,520 Speaker 2: in the History of Animals, the fourth century BCE text. 455 00:26:36,880 --> 00:26:39,399 Speaker 2: If you start looking searching around in that text for 456 00:26:39,560 --> 00:26:41,800 Speaker 2: mentions of the gecko, they do come up several times. 457 00:26:43,359 --> 00:26:47,520 Speaker 2: But he also writes of the amazing climbing ability of 458 00:26:47,560 --> 00:26:50,919 Speaker 2: the quote unquote gecko lizard to quote run up and 459 00:26:51,000 --> 00:26:54,440 Speaker 2: down a tree in any way, even with the head downwards. 460 00:26:55,160 --> 00:26:59,040 Speaker 2: So even Aristotle thought that this was pretty interesting, though 461 00:26:59,080 --> 00:27:02,160 Speaker 2: I don't believe he offers any possible explanation for it, 462 00:27:02,200 --> 00:27:03,960 Speaker 2: is just kind of an observation about you know, I 463 00:27:04,000 --> 00:27:05,840 Speaker 2: think he's comparing it to another creature. Here. 464 00:27:06,480 --> 00:27:10,719 Speaker 3: The quest to understand how gecko toes cling to all 465 00:27:10,800 --> 00:27:13,919 Speaker 3: these different surfaces and allow it to walk straight up 466 00:27:14,000 --> 00:27:17,840 Speaker 3: vertical walls of any roughness or smoothness, to cling to 467 00:27:17,920 --> 00:27:22,120 Speaker 3: ceilings and overhangs. This goes way way back, and people 468 00:27:22,160 --> 00:27:25,520 Speaker 3: have put forward tons of hypotheses over the years. Again, 469 00:27:25,560 --> 00:27:28,560 Speaker 3: coming back to our mission, impossible digression was due to 470 00:27:28,960 --> 00:27:31,720 Speaker 3: talking about suction cup climbing, and for a long time 471 00:27:32,200 --> 00:27:35,200 Speaker 3: a lot of people thought that the geckos did climb 472 00:27:35,240 --> 00:27:38,639 Speaker 3: by essentially using suction cup grips. But that's not the case. 473 00:27:39,040 --> 00:27:43,040 Speaker 2: Yeah, At different points they you know, hypotheses included sticky 474 00:27:43,080 --> 00:27:46,800 Speaker 2: secretions like we've mentioned, suction cups, also tiny hooks. You know, 475 00:27:46,840 --> 00:27:51,240 Speaker 2: these are all decent hypotheses to work with but it 476 00:27:51,280 --> 00:27:55,280 Speaker 2: didn't take too long for various naturalists and ultimately scientists 477 00:27:55,359 --> 00:27:57,679 Speaker 2: and thinkers in general to realize, well, none of these 478 00:27:57,720 --> 00:28:01,520 Speaker 2: are really explaining it. Something else is goinging on, and 479 00:28:01,600 --> 00:28:03,920 Speaker 2: it seems like it's something maybe more you know, more 480 00:28:03,920 --> 00:28:08,159 Speaker 2: physical certainly than chemical. But once again, like it's our 481 00:28:08,680 --> 00:28:10,720 Speaker 2: perspective and our language kind of get in the way 482 00:28:10,760 --> 00:28:14,560 Speaker 2: of like simple understanding of what the get go is doing. 483 00:28:15,000 --> 00:28:17,840 Speaker 2: And I find my experience with researching this it was 484 00:28:17,920 --> 00:28:20,679 Speaker 2: kind of like like the Powers of ten sort of 485 00:28:20,840 --> 00:28:24,440 Speaker 2: experiences ZUSA in you know, yes, because you start off 486 00:28:24,520 --> 00:28:27,479 Speaker 2: with like a simple question, well, why can gecko's climb walls? 487 00:28:27,640 --> 00:28:30,200 Speaker 2: And the answer is, well, because they have special flexible 488 00:28:30,359 --> 00:28:33,119 Speaker 2: adhesive ridges on their toes. And if you wanted, you 489 00:28:33,119 --> 00:28:35,560 Speaker 2: could stop there and be like, okay, question answered, I 490 00:28:35,560 --> 00:28:39,400 Speaker 2: can go home now. But but then you might ask 491 00:28:39,480 --> 00:28:43,240 Speaker 2: the follow up question, well, how do their adhesive toes work? Well, 492 00:28:43,280 --> 00:28:46,560 Speaker 2: the answer is the toes have special tiny hairs like 493 00:28:46,640 --> 00:28:49,160 Speaker 2: even you know, far smaller than what we think of 494 00:28:49,240 --> 00:28:53,440 Speaker 2: as hairs called ceta on them. And then you might say, okay, 495 00:28:53,520 --> 00:28:55,440 Speaker 2: I got it. I can go home now, that's what's 496 00:28:55,480 --> 00:28:55,840 Speaker 2: doing it. 497 00:28:56,800 --> 00:29:00,280 Speaker 3: But wait, yeah, how are the tiny hair What do 498 00:29:00,360 --> 00:29:02,520 Speaker 3: the tiny hairs do? Or how are they sticky? How 499 00:29:02,560 --> 00:29:03,720 Speaker 3: do they stick well? 500 00:29:03,800 --> 00:29:08,120 Speaker 2: Each of these has even smaller bristles called spatula on them. 501 00:29:08,360 --> 00:29:11,000 Speaker 3: Right, So, one way I've seen this described is all 502 00:29:11,040 --> 00:29:13,760 Speaker 3: these tiny little hairs. If you can zoom way way in, 503 00:29:13,960 --> 00:29:16,920 Speaker 3: like smaller on a scale smaller than you can see 504 00:29:16,960 --> 00:29:18,880 Speaker 3: with visible light. You have to use like a scanning 505 00:29:18,920 --> 00:29:23,720 Speaker 3: electron microscope, you can see that each hair like frayse 506 00:29:23,920 --> 00:29:26,600 Speaker 3: like a rope that just goes out to like millions 507 00:29:26,640 --> 00:29:30,600 Speaker 3: of little fibers that are beyond microscopic. They're down on 508 00:29:30,640 --> 00:29:35,640 Speaker 3: the nanoscale. They're super super tiny, frayed out to uncountable ends. 509 00:29:35,960 --> 00:29:38,640 Speaker 2: Yeah, I mean, there's so many that a given gecko 510 00:29:39,320 --> 00:29:42,160 Speaker 2: i've read have somewhere in the neighborhood of two billion 511 00:29:42,200 --> 00:29:45,560 Speaker 2: of these on the pads of their toes combined. 512 00:29:45,880 --> 00:29:49,760 Speaker 3: Okay, so on their toes they have these ridges. The ridges, 513 00:29:49,760 --> 00:29:51,920 Speaker 3: by the way, are called lamelli, and then on the 514 00:29:52,000 --> 00:29:55,880 Speaker 3: lamelly they have the setae, and the setae are little hairs, 515 00:29:55,920 --> 00:29:59,000 Speaker 3: and those hairs fray out into these little frayed bristly 516 00:29:59,120 --> 00:30:02,200 Speaker 3: ends called spatchel. But what does the spacially do. What 517 00:30:02,240 --> 00:30:03,800 Speaker 3: are those how do they work? 518 00:30:04,240 --> 00:30:08,440 Speaker 2: Well? The answer here is well, it's complicated, but the 519 00:30:08,840 --> 00:30:12,680 Speaker 2: basic idea is that their stickiness seems to depend on 520 00:30:12,760 --> 00:30:15,760 Speaker 2: a combination of intermolecular forces. 521 00:30:16,080 --> 00:30:19,160 Speaker 3: Yeah, it does seem like there are maybe multiple forces involved, 522 00:30:19,240 --> 00:30:22,240 Speaker 3: though the sources I was looking at zeroed in on 523 00:30:22,440 --> 00:30:25,840 Speaker 3: the most agreed upon explanation having to do with what 524 00:30:25,920 --> 00:30:27,720 Speaker 3: are known as Van Derval's forces. 525 00:30:28,040 --> 00:30:31,320 Speaker 2: Yes, van der Waals force named for Johannes Diedrich van 526 00:30:31,360 --> 00:30:35,240 Speaker 2: der Waals who lived eighteen thirty seven through nineteen twenty three. 527 00:30:36,400 --> 00:30:38,800 Speaker 2: There's an excellent two thousand and two article I've been 528 00:30:38,960 --> 00:30:43,160 Speaker 2: shouse that I that I One of the sources I 529 00:30:43,200 --> 00:30:46,400 Speaker 2: turned to for this section is you can find on 530 00:30:46,480 --> 00:30:50,280 Speaker 2: science dot org has the just perfect title how Geckos 531 00:30:50,360 --> 00:30:56,880 Speaker 2: stick on de valls at Waals spelling for walls. So yes, 532 00:30:56,920 --> 00:31:00,320 Speaker 2: that as of two thousand and two is to gused 533 00:31:00,320 --> 00:31:04,880 Speaker 2: in this article like that is the primary hypopsis for 534 00:31:05,040 --> 00:31:09,520 Speaker 2: how the gecko's toepads are ultimately sticking to the wall. 535 00:31:10,240 --> 00:31:12,400 Speaker 2: But another one that was being looked at at this 536 00:31:12,560 --> 00:31:15,520 Speaker 2: time in an article I'm going to side here is 537 00:31:15,560 --> 00:31:19,160 Speaker 2: this idea that it could have been water based capillary forces, 538 00:31:20,160 --> 00:31:22,800 Speaker 2: so like a thin film of water between pads and 539 00:31:22,840 --> 00:31:27,120 Speaker 2: the climbing surface. Quote. Because water molecules are polar, their 540 00:31:27,120 --> 00:31:30,520 Speaker 2: electrical charges aren't evenly distributed. They might stick to some 541 00:31:30,760 --> 00:31:32,960 Speaker 2: polar molecule in gecko's feet. 542 00:31:33,200 --> 00:31:36,080 Speaker 3: Oh okay. Now on the opposite side of that, what 543 00:31:36,120 --> 00:31:38,640 Speaker 3: I've been reading about gecko's feed is that they seem 544 00:31:38,680 --> 00:31:43,600 Speaker 3: to be composed largely of water repelling hydrophobic materials. But 545 00:31:43,880 --> 00:31:46,000 Speaker 3: that again, I think it's complicated. 546 00:31:46,400 --> 00:31:50,800 Speaker 2: Yes, yeah, Now to come back to vander Walls here, 547 00:31:51,920 --> 00:31:56,440 Speaker 2: science writer Eleanor Nelson put together a great explainer on 548 00:31:56,480 --> 00:31:59,360 Speaker 2: this whole topic for ted D several years ago. You 549 00:31:59,360 --> 00:32:01,320 Speaker 2: can look this up. There's a video on ted ED 550 00:32:01,360 --> 00:32:03,800 Speaker 2: about the gecko to search for ted ed gecko and 551 00:32:03,880 --> 00:32:06,160 Speaker 2: you can watch it as great visuals to help explain 552 00:32:06,200 --> 00:32:09,960 Speaker 2: all this. But she stresses that what we're talking about 553 00:32:10,000 --> 00:32:14,280 Speaker 2: here isn't attraction between charged molecules positive or negative, but 554 00:32:14,360 --> 00:32:20,240 Speaker 2: rather attractiveness between uncharged molecules that experience patches of negative 555 00:32:20,280 --> 00:32:23,720 Speaker 2: and positive charges due to the movement of atoms with 556 00:32:23,800 --> 00:32:28,920 Speaker 2: different electro negativities in the same molecule. So we're talking 557 00:32:28,960 --> 00:32:33,160 Speaker 2: about flickering patches of weak attraction. It's not strong in 558 00:32:33,240 --> 00:32:36,720 Speaker 2: isolation like each of those you know, tiny spatula are 559 00:32:36,760 --> 00:32:40,120 Speaker 2: not you know, pulling things across the room or anything 560 00:32:40,360 --> 00:32:44,080 Speaker 2: remotely like that. But when you have two billion of 561 00:32:44,080 --> 00:32:47,920 Speaker 2: these on a single gecko exploiting the force, it adds up. 562 00:32:48,040 --> 00:32:50,320 Speaker 2: In fact, it adds up so much that a gecko 563 00:32:50,400 --> 00:32:53,880 Speaker 2: can hang by a single digit, you know, from a 564 00:32:54,000 --> 00:32:57,480 Speaker 2: like a ceiling, you know. And it has complete control 565 00:32:57,520 --> 00:32:59,480 Speaker 2: over this as well, so you know, because they can 566 00:32:59,520 --> 00:33:02,960 Speaker 2: manipulate the angle and surface area of those tow ridges 567 00:33:03,360 --> 00:33:06,920 Speaker 2: in just the right way to activate and release that 568 00:33:07,080 --> 00:33:08,240 Speaker 2: stickiness on demand. 569 00:33:08,600 --> 00:33:11,840 Speaker 3: Yeah, it is amazing, especially when you notice like the 570 00:33:11,880 --> 00:33:14,960 Speaker 3: motor activities that the gecko has to coordinate to orient 571 00:33:15,120 --> 00:33:17,960 Speaker 3: these little harris correctly to always cling the right way. 572 00:33:18,920 --> 00:33:21,520 Speaker 3: But I wanted to clarify one thing because it took 573 00:33:21,520 --> 00:33:23,280 Speaker 3: me a minute to understand what was going on with 574 00:33:23,320 --> 00:33:28,240 Speaker 3: the Vandervals forces. The vanderwalls or Vanderval's forces are something 575 00:33:28,280 --> 00:33:30,800 Speaker 3: that is different from like the attraction you get in 576 00:33:30,840 --> 00:33:34,840 Speaker 3: a polar molecule like water, which is permanently polarized in 577 00:33:34,920 --> 00:33:36,880 Speaker 3: terms of a charge, so it's always going to be 578 00:33:36,920 --> 00:33:39,920 Speaker 3: able to attract one way or another because it's got 579 00:33:39,920 --> 00:33:42,160 Speaker 3: a you know, negative charge on one side, positive on 580 00:33:42,200 --> 00:33:46,760 Speaker 3: the other. The Vanderval's forces are, Yeah, they're due to 581 00:33:47,400 --> 00:33:53,080 Speaker 3: the fluctuations in the orientation of electrons around an atom 582 00:33:53,160 --> 00:33:56,720 Speaker 3: that are just random. So they just randomly change over time, 583 00:33:56,800 --> 00:33:59,680 Speaker 3: even when an atom is electrically stable, so this atom 584 00:33:59,720 --> 00:34:03,600 Speaker 3: is not polarized, but things just sort of flicker in 585 00:34:03,680 --> 00:34:06,360 Speaker 3: and out of existence. A charge attraction going one way 586 00:34:06,440 --> 00:34:09,640 Speaker 3: or the other flickers in and out of existence because 587 00:34:09,880 --> 00:34:14,120 Speaker 3: of just random fluctuations of where the electrons are lined up. 588 00:34:14,520 --> 00:34:19,040 Speaker 3: And that in cases where where atoms are packed close 589 00:34:19,160 --> 00:34:23,800 Speaker 3: enough together can actually have an attractive effect, but usually 590 00:34:23,880 --> 00:34:27,240 Speaker 3: atoms are not packed close enough together for that to matter. 591 00:34:28,000 --> 00:34:30,440 Speaker 2: Yeah, this is a if you're still foggy on this, 592 00:34:30,840 --> 00:34:32,920 Speaker 2: I do recommend that ted Ed video because they have 593 00:34:32,920 --> 00:34:36,640 Speaker 2: a nice animation that kind of that illustrates what's going 594 00:34:36,680 --> 00:34:39,000 Speaker 2: on here. At least for me, it helped clarify the 595 00:34:39,000 --> 00:34:39,520 Speaker 2: whole thing. 596 00:34:40,040 --> 00:34:42,319 Speaker 3: Yeah, and so the reason the spatuely are able to 597 00:34:42,360 --> 00:34:45,000 Speaker 3: take advantage of the Vanderwolts force is because they're so 598 00:34:45,239 --> 00:34:47,239 Speaker 3: tiny and there's so many of them. 599 00:34:47,960 --> 00:35:00,160 Speaker 2: Forests of them, I've seen it described a right. So 600 00:35:00,239 --> 00:35:04,080 Speaker 2: coming back to the two thousand and two time period here, 601 00:35:04,440 --> 00:35:07,279 Speaker 2: there was a paper that came out in a two 602 00:35:07,320 --> 00:35:10,680 Speaker 2: thousand and two edition of Integrative and Comparative Biology titled 603 00:35:11,239 --> 00:35:16,520 Speaker 2: Mechanisms of Adhesion in Geckos. This was by Keller autumn 604 00:35:16,560 --> 00:35:20,640 Speaker 2: at All and in this they were exploring the vendor 605 00:35:20,680 --> 00:35:25,239 Speaker 2: val and the water based capillary forces explanations to you know, see, okay, well, 606 00:35:25,680 --> 00:35:28,200 Speaker 2: let's look at these two possible ideas and see which 607 00:35:28,200 --> 00:35:33,720 Speaker 2: one seems to seems more evident when put to the test. 608 00:35:34,080 --> 00:35:37,960 Speaker 2: And they used the aid of semiconductors, so they ruled 609 00:35:38,000 --> 00:35:42,840 Speaker 2: out water droplet hypothesis as it depends on polar surfaces. 610 00:35:43,080 --> 00:35:46,200 Speaker 2: They found in their experiments that geckos could equally climb 611 00:35:46,200 --> 00:35:49,839 Speaker 2: a non polar surface. In this experiment they used a 612 00:35:49,880 --> 00:35:54,840 Speaker 2: semiconductor called gallium arsenide, which is a compound of gallium 613 00:35:54,840 --> 00:35:58,840 Speaker 2: and arsenic. By the way, it is also interesting that 614 00:35:58,880 --> 00:36:03,560 Speaker 2: gecko feet can not adhere to teflon. You may have 615 00:36:03,800 --> 00:36:07,040 Speaker 2: heard this or seen some headlines about this over the years, 616 00:36:07,080 --> 00:36:11,400 Speaker 2: but according to Sarah Chodesh on Popular Science back in 617 00:36:11,400 --> 00:36:16,480 Speaker 2: twenty eighteen, teflon disrupts the Vanderval's force effect here that 618 00:36:16,640 --> 00:36:19,600 Speaker 2: enables them to climb other or seems to be one of, 619 00:36:19,680 --> 00:36:22,320 Speaker 2: if not the primary factors in their ability to climb 620 00:36:22,320 --> 00:36:26,000 Speaker 2: other surfaces. Quote. Vanderval's forces depend on being able to 621 00:36:26,040 --> 00:36:29,480 Speaker 2: induce a positive and negative end of a molecule or atom. 622 00:36:29,640 --> 00:36:32,600 Speaker 2: But the layer of fluorines in Teflon just have this 623 00:36:32,760 --> 00:36:36,920 Speaker 2: permanent negative charge to them. The electrons stay in one place. 624 00:36:37,400 --> 00:36:39,560 Speaker 3: Teflon's not having any of it. Yeah. 625 00:36:40,239 --> 00:36:42,880 Speaker 2: So anyway, that twenty and two study backs up the 626 00:36:42,960 --> 00:36:46,640 Speaker 2: vandervals explanation. In their own words, their findings at the 627 00:36:46,680 --> 00:36:50,239 Speaker 2: time provided quote direct evidence that Vanderval's force is the 628 00:36:50,280 --> 00:36:54,520 Speaker 2: mechanism of adhesion in get Go ceta and that water 629 00:36:54,560 --> 00:36:58,680 Speaker 2: based capillary forces are not significant. So again not to 630 00:36:58,719 --> 00:37:01,040 Speaker 2: say it couldn't be doing something, but it's not the 631 00:37:01,120 --> 00:37:02,120 Speaker 2: significant factor. 632 00:37:02,920 --> 00:37:06,719 Speaker 3: Yes, though it's interesting. In uh the chapter in Winkless's 633 00:37:06,760 --> 00:37:11,200 Speaker 3: book on gecko toes, she talks about, how you know, 634 00:37:11,280 --> 00:37:14,719 Speaker 3: it seems like most researchers in this area kind of agree, Yeah, 635 00:37:14,719 --> 00:37:19,839 Speaker 3: it's Vanderval's force. That's that's the explanation or the main explanation. 636 00:37:19,920 --> 00:37:22,120 Speaker 3: But she says, they all kind of have this bit 637 00:37:22,160 --> 00:37:25,319 Speaker 3: of hesitation when they talk about it, like maybe there's 638 00:37:25,320 --> 00:37:28,080 Speaker 3: something else going on too that we haven't fully figured 639 00:37:28,080 --> 00:37:29,240 Speaker 3: out yet. Yeah. 640 00:37:29,320 --> 00:37:33,200 Speaker 2: I kept thinking about like the experience of trying like 641 00:37:33,239 --> 00:37:35,640 Speaker 2: a fancy cocktail somewhere and you're trying to pick out 642 00:37:35,640 --> 00:37:38,359 Speaker 2: the ingredients just on taste. You know, generally you can 643 00:37:38,440 --> 00:37:40,279 Speaker 2: you can pick out some of the major flavors. But 644 00:37:41,440 --> 00:37:44,479 Speaker 2: are you gonna, you know, absolutely put your money down 645 00:37:44,719 --> 00:37:47,759 Speaker 2: that there are only three ingredients in this cocktail and 646 00:37:47,800 --> 00:37:51,960 Speaker 2: you're there are not four, they're not five, and so forth. 647 00:37:52,360 --> 00:37:55,120 Speaker 3: That's right. What's that tingling in the back of your mouth? 648 00:37:55,400 --> 00:37:57,240 Speaker 3: Could that be an absentthe rense? 649 00:37:59,239 --> 00:38:03,279 Speaker 2: So one sample of this concerning gecko feed This comes 650 00:38:03,360 --> 00:38:06,520 Speaker 2: up in a twenty fourteen article that I was looking 651 00:38:06,560 --> 00:38:11,600 Speaker 2: at role of contact electrification and electrostatic interactions in gecko 652 00:38:11,600 --> 00:38:14,440 Speaker 2: adhesion by A. Zadi at All published in the Journal 653 00:38:14,680 --> 00:38:19,200 Speaker 2: of the Royal Society Interface, and this one discusses the 654 00:38:19,360 --> 00:38:24,759 Speaker 2: CE driven electrostatic interaction. This refers to the contact electrification phenomenon, 655 00:38:25,200 --> 00:38:29,440 Speaker 2: and I understand that this is still controversial. For example, 656 00:38:29,480 --> 00:38:31,799 Speaker 2: in a twenty twenty three paper by song at All, 657 00:38:32,200 --> 00:38:35,319 Speaker 2: in published in the journal Friction. The author's cite the 658 00:38:35,480 --> 00:38:39,240 Speaker 2: controversial aspect of the CE driven explanation, though to be clear, 659 00:38:39,480 --> 00:38:43,440 Speaker 2: it's ultimately more about the level of contribution that's controversial, 660 00:38:43,640 --> 00:38:46,879 Speaker 2: because again it's like saying, well, yes, I think there's 661 00:38:46,880 --> 00:38:50,680 Speaker 2: absinth in this cocktail, but maybe it's just a drop. 662 00:38:50,800 --> 00:38:53,320 Speaker 2: It's like three drops of absinthe I'm not saying it's 663 00:38:53,400 --> 00:38:57,960 Speaker 2: anything more than that, Whereas there might be someone else arguing, actually, 664 00:38:58,040 --> 00:38:59,799 Speaker 2: I think they put an ounce in there, and then 665 00:38:59,800 --> 00:39:04,560 Speaker 2: the fighting and controversy. But anyway, in this song at 666 00:39:04,560 --> 00:39:09,360 Speaker 2: all paper the way they explain it, it seems like 667 00:39:10,480 --> 00:39:14,040 Speaker 2: CE may be part of the situation, but their study 668 00:39:14,080 --> 00:39:18,000 Speaker 2: suggests that its impact is low, perhaps contributing only around 669 00:39:18,400 --> 00:39:21,840 Speaker 2: three percent of the adhesiveness, and this may also be 670 00:39:21,960 --> 00:39:24,719 Speaker 2: why it doesn't help them out with something like teflin, 671 00:39:25,040 --> 00:39:29,040 Speaker 2: which again essentially cancels out Vanderval's force, which, as far 672 00:39:29,080 --> 00:39:31,920 Speaker 2: as we can tell, seems to be the primary factor 673 00:39:32,120 --> 00:39:35,440 Speaker 2: in play here. However, they note that quote long range 674 00:39:35,480 --> 00:39:39,360 Speaker 2: electrostatic forces may play other roles in a distance range 675 00:39:39,440 --> 00:39:43,640 Speaker 2: where the Vanderwals interaction cannot function, So again there could 676 00:39:43,680 --> 00:39:46,640 Speaker 2: be certain situations where it's more important to some degree 677 00:39:46,719 --> 00:39:47,440 Speaker 2: than other times. 678 00:39:47,880 --> 00:39:50,319 Speaker 3: But it does seem clear that whatever else is going on, 679 00:39:50,400 --> 00:39:53,360 Speaker 3: the main ingredient, the whiskey in the cocktail is the 680 00:39:53,480 --> 00:39:58,360 Speaker 3: vandervals interaction. Yes, and another interesting thing here, Rob you 681 00:39:58,440 --> 00:40:02,279 Speaker 3: alluded to this earlier, but it's something that you can 682 00:40:02,360 --> 00:40:06,600 Speaker 3: notice if you watch a gecko actually climbing, which is 683 00:40:06,680 --> 00:40:10,440 Speaker 3: the question of wait, how do they make their toes 684 00:40:10,600 --> 00:40:13,960 Speaker 3: stick and then unstick? So they've got this really powerful 685 00:40:13,960 --> 00:40:18,560 Speaker 3: sticking force, and in some cases the sticking force it 686 00:40:18,600 --> 00:40:21,080 Speaker 3: can hold so much more than the weight of a 687 00:40:21,080 --> 00:40:24,480 Speaker 3: gecko's body. There's one estimate in Winkliss's book about a 688 00:40:24,520 --> 00:40:26,799 Speaker 3: test showing that a gecko I can't remember, I didn't 689 00:40:26,800 --> 00:40:29,480 Speaker 3: write down the number, but it's like a gecko's grip 690 00:40:29,520 --> 00:40:33,440 Speaker 3: could hold hundreds of pounds up on the wall, despite 691 00:40:33,440 --> 00:40:35,640 Speaker 3: the fact that the gecko itself only weighs like half 692 00:40:35,640 --> 00:40:38,279 Speaker 3: a pound. Now, on one hand, you might think, well, 693 00:40:38,280 --> 00:40:40,719 Speaker 3: that's kind of overkill, but of course that would be 694 00:40:41,239 --> 00:40:43,920 Speaker 3: testing it in sort of ideal conditions in a lab, 695 00:40:43,960 --> 00:40:46,359 Speaker 3: whereas in nature a lot of times the surfaces it's 696 00:40:46,360 --> 00:40:48,680 Speaker 3: climbing on are going to be dirty, which will reduce 697 00:40:48,760 --> 00:40:52,720 Speaker 3: the adhesive potential, might be wet, which would potentially reduce 698 00:40:52,719 --> 00:40:56,520 Speaker 3: adhesive potential. Some of their toes might be injured or something. 699 00:40:56,640 --> 00:41:00,520 Speaker 3: Some of the lamilly might come off. In nature, you know, 700 00:41:00,600 --> 00:41:02,960 Speaker 3: it's better safe than sorry. When you're a gecko, have 701 00:41:03,440 --> 00:41:06,720 Speaker 3: a lot of sticking power. But yeah, anyway, the question 702 00:41:06,840 --> 00:41:09,319 Speaker 3: is how does it stick and unstick and climb in 703 00:41:09,320 --> 00:41:11,360 Speaker 3: different directions? And a lot of this comes down to 704 00:41:11,760 --> 00:41:15,800 Speaker 3: how it lifts and attaches its toes to the surface 705 00:41:16,239 --> 00:41:18,799 Speaker 3: and how it orients them. So like you, if you 706 00:41:18,880 --> 00:41:22,800 Speaker 3: watch a gecko crawling up a wall, it will tend 707 00:41:22,840 --> 00:41:26,680 Speaker 3: to sort of like peel its peel its toes up 708 00:41:26,960 --> 00:41:28,960 Speaker 3: and then lay them down with all of the toes 709 00:41:29,000 --> 00:41:31,600 Speaker 3: facing upward on the wall. But if you see a 710 00:41:31,600 --> 00:41:35,319 Speaker 3: gecko climbing down a wall, it will rotate its back 711 00:41:35,360 --> 00:41:38,800 Speaker 3: feet so that its toes are facing up. Because the 712 00:41:39,800 --> 00:41:43,920 Speaker 3: ceta and the spatually on them, they sort of only 713 00:41:44,000 --> 00:41:46,640 Speaker 3: grip effectively when laying in one direction. 714 00:41:47,480 --> 00:41:50,040 Speaker 2: Yeah, one way to think about all this is that again, 715 00:41:50,160 --> 00:41:54,040 Speaker 2: our understanding of what's going on when a gecko climbs 716 00:41:54,800 --> 00:41:59,440 Speaker 2: has not reached a level of perfection, but their exploitation 717 00:42:00,200 --> 00:42:03,840 Speaker 2: of it has reached perfection, like they are the perfect 718 00:42:04,239 --> 00:42:08,480 Speaker 2: manipulators of this force. So it's pretty amazing to watch. 719 00:42:08,880 --> 00:42:13,200 Speaker 3: Now, whenever evolution achieves something this ingenious, you will bet 720 00:42:13,280 --> 00:42:15,960 Speaker 3: that human engineers come running to see, how are they? 721 00:42:16,440 --> 00:42:18,839 Speaker 3: How are they doing that? What's going on there? Could 722 00:42:18,880 --> 00:42:21,080 Speaker 3: I make robots that could do something like that? 723 00:42:21,360 --> 00:42:26,640 Speaker 2: Yeah? Yeah, So of course biomimicry has gazed longingly at 724 00:42:26,640 --> 00:42:29,840 Speaker 2: the gecko for a while now. There have been various 725 00:42:29,840 --> 00:42:33,840 Speaker 2: efforts to create artificial ct with some working prototypes and 726 00:42:33,960 --> 00:42:38,160 Speaker 2: robotics and even human climbing suits popping up in headlines. 727 00:42:38,200 --> 00:42:39,880 Speaker 2: I think there was a DARPA project that made the 728 00:42:39,880 --> 00:42:43,799 Speaker 2: news in twenty fourteen. These have certainly not reached a 729 00:42:44,000 --> 00:42:47,319 Speaker 2: level of perfection yet, but you know, there are some 730 00:42:47,400 --> 00:42:50,960 Speaker 2: interesting applications out there potentially for this, and they're not 731 00:42:51,000 --> 00:42:54,520 Speaker 2: all of them involved like super soldiers climbing the windshield 732 00:42:54,960 --> 00:42:59,640 Speaker 2: or robots cleaning you know, high rise buildings, for instance. 733 00:42:59,640 --> 00:43:01,960 Speaker 2: It's been put far that they could be used in 734 00:43:02,000 --> 00:43:05,000 Speaker 2: low gravity environments. They could even be used, you know, 735 00:43:05,080 --> 00:43:07,719 Speaker 2: to collect space debris in orbit, that sort of thing. 736 00:43:08,200 --> 00:43:11,200 Speaker 3: So the amount of weight that can be supported by 737 00:43:11,320 --> 00:43:14,080 Speaker 3: a gecko's toes and the range over the range of 738 00:43:14,080 --> 00:43:17,640 Speaker 3: different surfaces that they can crawl over is truly astounding 739 00:43:17,680 --> 00:43:20,560 Speaker 3: and sort of a superlative in nature. But there are 740 00:43:20,600 --> 00:43:23,880 Speaker 3: lots of other animals that can crawl up walls, and 741 00:43:23,960 --> 00:43:27,000 Speaker 3: I wonder do many of them make use of similar 742 00:43:27,320 --> 00:43:29,240 Speaker 3: mechanisms or forces well. 743 00:43:29,520 --> 00:43:32,200 Speaker 2: Spiders climb in a similar way and also depend on 744 00:43:32,600 --> 00:43:36,880 Speaker 2: tiny set that make use of Vanderval's force. Though they're 745 00:43:37,120 --> 00:43:40,080 Speaker 2: ultimately like masters of these structures, they also use them 746 00:43:40,080 --> 00:43:45,720 Speaker 2: for other purposes as well, like like sensing sense sounds, vibrations, 747 00:43:45,760 --> 00:43:49,640 Speaker 2: and air currents. But this does lead us back to 748 00:43:49,680 --> 00:43:54,360 Speaker 2: the topic of Spider Man, because, as everyone knows, Spider 749 00:43:54,360 --> 00:44:00,160 Speaker 2: Man can do whatever a spider can, and it's this. 750 00:44:00,239 --> 00:44:03,319 Speaker 3: He can liquefy your innards and slurp them out through 751 00:44:03,320 --> 00:44:04,520 Speaker 3: his mouth orifice. 752 00:44:05,120 --> 00:44:07,640 Speaker 2: Maybe he can, and he chooses not to, But I 753 00:44:07,640 --> 00:44:09,640 Speaker 2: guess that's more of a Isn't there a man There's 754 00:44:09,640 --> 00:44:11,560 Speaker 2: a man spid. I know there's a batman and a 755 00:44:11,800 --> 00:44:15,880 Speaker 2: man bat there's also like a spider man monster creature, 756 00:44:15,920 --> 00:44:18,200 Speaker 2: but I don't know if that's man spider or not 757 00:44:18,719 --> 00:44:21,200 Speaker 2: off the top of my head. But it gets it 758 00:44:21,200 --> 00:44:24,239 Speaker 2: gets so complicated when you start comparing Spider Man to 759 00:44:24,560 --> 00:44:26,759 Speaker 2: spiders because, of course there are all these things that 760 00:44:26,800 --> 00:44:29,440 Speaker 2: don't match up. For example, it's easy to think of 761 00:44:29,480 --> 00:44:31,400 Speaker 2: Spider Man. What does Spider Man do well? He swings 762 00:44:31,440 --> 00:44:35,480 Speaker 2: around on webbing through the through the streets, though he 763 00:44:35,520 --> 00:44:38,239 Speaker 2: does so in a way that's not particularly spider esque, 764 00:44:38,560 --> 00:44:42,360 Speaker 2: and while in some adaptations of Spider Man he's using 765 00:44:42,960 --> 00:44:46,600 Speaker 2: like organic like mutations, like he has like he's you know, 766 00:44:46,640 --> 00:44:49,040 Speaker 2: he's been by a radioactive spider and now he can 767 00:44:49,320 --> 00:44:52,680 Speaker 2: he can shoot webbing out of his wrists. Most versions 768 00:44:52,680 --> 00:44:55,600 Speaker 2: of Spider Man you encounter he has these little gadgets 769 00:44:55,600 --> 00:44:58,560 Speaker 2: that he built that shoot some sort of nylon like webbing. 770 00:44:58,680 --> 00:45:01,040 Speaker 2: So he's this weird mix of like, Okay, I'm part 771 00:45:01,120 --> 00:45:04,160 Speaker 2: Spider but also I have like super crazy sci fi 772 00:45:04,280 --> 00:45:07,319 Speaker 2: weapons as well, and all of these combined to make 773 00:45:07,360 --> 00:45:09,080 Speaker 2: me able to do whatever a spider kit. 774 00:45:09,520 --> 00:45:11,719 Speaker 3: It's not really satisfying that way, is it. He's one 775 00:45:11,719 --> 00:45:14,040 Speaker 3: foot in each world. He's half a Charles B. Griffith 776 00:45:14,120 --> 00:45:17,839 Speaker 3: script where yes it was atomic radiation. But he's half 777 00:45:17,920 --> 00:45:21,400 Speaker 3: Batman and we already have Batman. He makes gadgets. 778 00:45:21,480 --> 00:45:23,399 Speaker 2: Yeah, I mean, I guess I'm not a Spider Man 779 00:45:23,440 --> 00:45:27,799 Speaker 2: purist or anything, but I like the mutant version. I 780 00:45:27,880 --> 00:45:29,640 Speaker 2: like the idea that he's shooting it out of his wrist, 781 00:45:29,760 --> 00:45:33,000 Speaker 2: even though that doesn't really match up. Like spiders don't 782 00:45:33,440 --> 00:45:36,840 Speaker 2: they have spinnerets, they don't have wrist openings or whatever. 783 00:45:36,920 --> 00:45:40,120 Speaker 2: So you know, it's still not one to one. 784 00:45:40,160 --> 00:45:42,879 Speaker 3: I guess Spider Man fans, please don't hate me. I'm 785 00:45:42,880 --> 00:45:45,239 Speaker 3: just joking around. I don't know much about Spider Man. 786 00:45:45,600 --> 00:45:49,120 Speaker 2: I mean, Spider Man is great. But one of Spider 787 00:45:49,120 --> 00:45:53,120 Speaker 2: Man's abilities that is or seems to be universally accepted 788 00:45:53,120 --> 00:45:56,080 Speaker 2: as an ability brought on by the radioactive spider bite 789 00:45:56,320 --> 00:45:59,440 Speaker 2: is his ability to climb walls and stick to ceilings 790 00:45:59,719 --> 00:46:02,080 Speaker 2: with out the aid of his wedding. How does he 791 00:46:02,160 --> 00:46:05,960 Speaker 2: do this well? On one hand, we have to admit 792 00:46:06,000 --> 00:46:07,600 Speaker 2: like this is a fool's errand to try and make 793 00:46:07,640 --> 00:46:11,960 Speaker 2: sense of this. Spider Man climbs walls because he's Spider Man, 794 00:46:11,440 --> 00:46:16,000 Speaker 2: and any kind of like scientific explanation to this comes 795 00:46:16,080 --> 00:46:20,000 Speaker 2: after the fact they were not thinking long and hard 796 00:46:20,040 --> 00:46:22,839 Speaker 2: about the anatomy of a spider when they came up 797 00:46:22,880 --> 00:46:26,719 Speaker 2: with this character. As fun as this character is, so 798 00:46:26,880 --> 00:46:31,040 Speaker 2: any attempt to scientifically explain everything about him is is. 799 00:46:31,360 --> 00:46:33,279 Speaker 2: It can be very fun, but it's not going to 800 00:46:33,280 --> 00:46:35,960 Speaker 2: get you to a place of absolute certainty. 801 00:46:36,440 --> 00:46:39,920 Speaker 3: You might as well ask, exactly scientifically, how do the 802 00:46:40,000 --> 00:46:42,640 Speaker 3: crabs in attack of the crab monsters eat your brains 803 00:46:42,680 --> 00:46:44,600 Speaker 3: and gain your knowledge exactly? 804 00:46:45,320 --> 00:46:47,399 Speaker 2: But like I say, it's a fun exercise, and I've 805 00:46:47,400 --> 00:46:51,880 Speaker 2: been enjoying this book marvel Anatomy by Sumeruk and Wallace, 806 00:46:52,440 --> 00:46:55,120 Speaker 2: and the authors point out several things about Spider Man's 807 00:46:55,160 --> 00:46:57,600 Speaker 2: adhesive abilities and how they match up or don't match 808 00:46:57,680 --> 00:46:59,960 Speaker 2: up with the natural world. One of the main ishu 809 00:47:01,200 --> 00:47:04,480 Speaker 2: that they keep talking about, though, is Okay, Spider Man 810 00:47:04,640 --> 00:47:07,480 Speaker 2: can climb, and perhaps he does this because he has 811 00:47:07,520 --> 00:47:10,640 Speaker 2: little CD on his hands at least or I guess, 812 00:47:10,680 --> 00:47:13,240 Speaker 2: over his entire body, and it allows him to adhere 813 00:47:13,280 --> 00:47:16,480 Speaker 2: to walls. But also he's wearing a full body costume. 814 00:47:17,080 --> 00:47:21,200 Speaker 2: Spider Man is almost never naked when he's clinging to 815 00:47:21,320 --> 00:47:25,080 Speaker 2: walls and so forth, so it raises questions like would 816 00:47:25,200 --> 00:47:29,640 Speaker 2: vander walls work through a pair of spider gloves or 817 00:47:29,680 --> 00:47:31,960 Speaker 2: would that weaken it to some degree. 818 00:47:32,280 --> 00:47:34,120 Speaker 3: I don't think it would work, because the whole thing 819 00:47:34,120 --> 00:47:36,720 Speaker 3: about Vanderval's force is you've got to be incredibly close, 820 00:47:36,800 --> 00:47:39,960 Speaker 3: closer than solids can usually get to each other. That's like, 821 00:47:40,120 --> 00:47:42,919 Speaker 3: that's why the gecko's foot works. It's the tiny little 822 00:47:43,000 --> 00:47:45,120 Speaker 3: thing that can get in there in the cracks and 823 00:47:45,160 --> 00:47:47,600 Speaker 3: crevices in the surface, unlike anything else. 824 00:47:48,080 --> 00:47:51,040 Speaker 2: Well, the author suggests that, well, maybe the ceed poke 825 00:47:51,200 --> 00:47:54,800 Speaker 2: through the costume, but that raises all sorts of questions, 826 00:47:54,840 --> 00:47:56,640 Speaker 2: like then when he takes the costume off, when he 827 00:47:56,680 --> 00:47:58,799 Speaker 2: peels off the sweaty Spider Man costume at the end 828 00:47:58,800 --> 00:48:00,640 Speaker 2: of the day, does it just rich them all off 829 00:48:00,680 --> 00:48:03,239 Speaker 2: and he has to regrow them or I don't know. 830 00:48:03,280 --> 00:48:06,000 Speaker 2: It's a wonder fabric that Iron Man made for him, 831 00:48:06,000 --> 00:48:07,919 Speaker 2: so it lets them out. 832 00:48:08,080 --> 00:48:08,520 Speaker 3: I don't know. 833 00:48:09,200 --> 00:48:12,520 Speaker 2: Again, it just raises more questions than anything. 834 00:48:13,480 --> 00:48:16,800 Speaker 3: I think Spider Man should have finger gloves like a bandit. 835 00:48:17,320 --> 00:48:20,920 Speaker 2: The authors here suggest that maybe Spider Man can actually 836 00:48:21,000 --> 00:48:25,960 Speaker 2: quote consciously control the intra atomic attraction between molecular boundary layers, 837 00:48:26,880 --> 00:48:30,120 Speaker 2: which I suppose sounds reasonable, though I mean this raises 838 00:48:30,160 --> 00:48:33,080 Speaker 2: the question about to what extent this still makes sense 839 00:48:33,120 --> 00:48:36,880 Speaker 2: as a sixties at comic book. Radiation Advancement of natural 840 00:48:36,880 --> 00:48:41,120 Speaker 2: World spider abilities, but I'll take it. I'll take it. 841 00:48:41,160 --> 00:48:43,840 Speaker 2: Sounds good to me. Now. They do point out that 842 00:48:43,920 --> 00:48:46,760 Speaker 2: another character, Spider Woman. I don't know if you're familiar 843 00:48:46,800 --> 00:48:49,960 Speaker 2: with Spider Woman. She was introduced in nineteen seventy seven. 844 00:48:51,080 --> 00:48:54,440 Speaker 2: She just kind of like a red outfit. But she 845 00:48:54,600 --> 00:48:59,040 Speaker 2: is said to be able to climb via secreted biological 846 00:48:59,120 --> 00:49:03,560 Speaker 2: adhesive substances that are on her hands and her feet 847 00:49:04,120 --> 00:49:09,000 Speaker 2: that I guess swiftly penetrate tiny pores in the climbing surface. Also, 848 00:49:09,480 --> 00:49:13,560 Speaker 2: she wears gloves and booties as well, so this secretion 849 00:49:13,680 --> 00:49:17,200 Speaker 2: would have to like rapidly soak through the fabric in 850 00:49:17,239 --> 00:49:19,680 Speaker 2: these cases as well or through the booties and then 851 00:49:19,719 --> 00:49:22,520 Speaker 2: allow her to stick to the walls. And again this 852 00:49:22,600 --> 00:49:25,240 Speaker 2: raises more questions because when you look to the natural world, 853 00:49:25,480 --> 00:49:29,879 Speaker 2: you do see adhesive secretions in some organisms, but they 854 00:49:29,920 --> 00:49:32,759 Speaker 2: tend to be defensive rather than climbing aids. These are 855 00:49:32,800 --> 00:49:36,360 Speaker 2: things that you would extrude when threatened, so that whatever 856 00:49:36,480 --> 00:49:38,319 Speaker 2: was trying to eat you might decide, oh, I don't 857 00:49:38,360 --> 00:49:39,000 Speaker 2: want any of this. 858 00:49:39,960 --> 00:49:43,440 Speaker 3: Yeah, well, maybe I'm not thinking creatively enough, but it 859 00:49:43,480 --> 00:49:47,760 Speaker 3: seems like if you had to secrete enough sticky stuff 860 00:49:47,960 --> 00:49:49,640 Speaker 3: to hold you to a wall every time you wanted 861 00:49:49,640 --> 00:49:51,400 Speaker 3: to climb. That'd just be a lot of stuff that 862 00:49:51,480 --> 00:49:55,120 Speaker 3: sounds like you're secreting, Like do you get dehydrated? Do 863 00:49:55,160 --> 00:49:57,319 Speaker 3: you run out of energy doing that? Well? 864 00:49:57,360 --> 00:50:00,799 Speaker 2: I mean, Spider Man is leaving nylon thread all over 865 00:50:00,840 --> 00:50:03,320 Speaker 2: the city, all over New York as he's fighting crime, 866 00:50:03,440 --> 00:50:06,200 Speaker 2: and I guess somebody has to clean that up. They 867 00:50:06,200 --> 00:50:08,200 Speaker 2: probably didn't think about it much in the sixties, and 868 00:50:08,200 --> 00:50:10,480 Speaker 2: I guess it was acceptable in the eighties, but nowadays, 869 00:50:10,800 --> 00:50:14,799 Speaker 2: like it's what's the what's the environmental impact of this 870 00:50:14,880 --> 00:50:15,520 Speaker 2: crime fighting? 871 00:50:16,160 --> 00:50:18,560 Speaker 3: But once again the genius of the gecko. The gecko 872 00:50:18,600 --> 00:50:19,600 Speaker 3: climbs without goop. 873 00:50:20,280 --> 00:50:24,440 Speaker 2: Yes, yeah, And the authors here they do include a 874 00:50:24,440 --> 00:50:27,960 Speaker 2: bit on one of Spider Man's many enemies. You've perhaps 875 00:50:27,960 --> 00:50:30,000 Speaker 2: heard of, the lizard. I think the lizard was in 876 00:50:30,200 --> 00:50:32,600 Speaker 2: at least one of the movies. I can't remember which 877 00:50:32,600 --> 00:50:36,920 Speaker 2: Spider Man this was, which Spider Man regime, But this 878 00:50:37,080 --> 00:50:40,200 Speaker 2: is a man, a scientist who turns into a great, 879 00:50:40,239 --> 00:50:44,520 Speaker 2: big green lizard and chases Spider Man around. And in 880 00:50:44,640 --> 00:50:47,520 Speaker 2: many of the depictions, the lizard can climb around on 881 00:50:47,640 --> 00:50:51,279 Speaker 2: walls and on the ceiling. In this particular book that 882 00:50:51,320 --> 00:50:53,680 Speaker 2: I was referring to, they discuss it as more of 883 00:50:53,719 --> 00:50:55,680 Speaker 2: a claw thing, which I think makes sense for a 884 00:50:55,719 --> 00:50:58,400 Speaker 2: super villain, you know, big nasty claws. Can you know 885 00:50:59,640 --> 00:51:03,239 Speaker 2: claw into the concrete? Is the creatures climbing around. But 886 00:51:03,320 --> 00:51:08,040 Speaker 2: I've also seen some descriptions that discuss the lizard as 887 00:51:08,120 --> 00:51:09,759 Speaker 2: having gecko abilities. 888 00:51:10,400 --> 00:51:14,080 Speaker 3: Oh okay, so either way claw or gecko, that would 889 00:51:14,080 --> 00:51:17,799 Speaker 3: be San's goop. That would be a mechanical grip of 890 00:51:17,840 --> 00:51:20,560 Speaker 3: some sort or of Vandervohal's force. Yeah. 891 00:51:20,640 --> 00:51:24,400 Speaker 2: But again, I think with a super villain like the Lizard, 892 00:51:24,440 --> 00:51:29,640 Speaker 2: it makes more sense that his climbing ability is visibly destructive, 893 00:51:31,360 --> 00:51:33,480 Speaker 2: though it raises the question like, where's the love for 894 00:51:33,600 --> 00:51:37,200 Speaker 2: the gecko? Then in the creation of Superheroes, I was 895 00:51:37,239 --> 00:51:39,839 Speaker 2: looking around looking at the various databases, and it looks 896 00:51:39,880 --> 00:51:43,200 Speaker 2: like they're a couple of minor Marvel Gecko characters, or 897 00:51:43,200 --> 00:51:46,840 Speaker 2: maybe it's two versions of one character that have existed. 898 00:51:46,880 --> 00:51:49,600 Speaker 2: And it looks like DC Comics also has a Gecko 899 00:51:49,760 --> 00:51:52,319 Speaker 2: or the Gecko. But I don't get this sense that 900 00:51:52,320 --> 00:51:55,600 Speaker 2: these are based on anything, you know, true to the 901 00:51:55,640 --> 00:51:59,759 Speaker 2: get go. But comic book fans out there let us 902 00:51:59,760 --> 00:52:02,719 Speaker 2: know perhaps you have more detail on these Geckos. 903 00:52:03,400 --> 00:52:06,960 Speaker 3: Who is Gordon Gecko? Is he some kind of gecko supervillain? 904 00:52:08,320 --> 00:52:11,360 Speaker 2: I don't know. Maybe it's part of the shared cinematic universe. 905 00:52:11,640 --> 00:52:13,320 Speaker 3: Okay, I think that's all we got for today. 906 00:52:13,560 --> 00:52:15,160 Speaker 2: All right, We're going to go ahead wrap it up here, 907 00:52:15,160 --> 00:52:16,719 Speaker 2: but yeah, write in let us know what you think 908 00:52:16,719 --> 00:52:21,560 Speaker 2: about stickiness in general, the examples of stickiness that we've discussed, 909 00:52:21,840 --> 00:52:26,480 Speaker 2: and yes, even fictional sticky comic book characters and so forth. 910 00:52:26,880 --> 00:52:29,239 Speaker 2: Just a reminder that we're primarily a science podcast here 911 00:52:29,280 --> 00:52:31,000 Speaker 2: at Stuff to Blow Your Mind, with core episodes on 912 00:52:31,040 --> 00:52:35,000 Speaker 2: Tuesdays and Thursdays, listener mail on Mondays, a short form 913 00:52:35,040 --> 00:52:38,160 Speaker 2: monster fact or artifact episode on Wednesdays, and on Fridays. 914 00:52:38,160 --> 00:52:40,160 Speaker 2: We set aside most serious concerns. Who just talk about 915 00:52:40,160 --> 00:52:42,160 Speaker 2: a weird film on Weird House Cinema. 916 00:52:42,320 --> 00:52:45,920 Speaker 3: Huge thanks to our excellent audio producer JJ Posway. If 917 00:52:45,920 --> 00:52:47,440 Speaker 3: you would like to get in touch with us with 918 00:52:47,520 --> 00:52:49,920 Speaker 3: feedback on this episode or any other, to suggest a 919 00:52:49,960 --> 00:52:52,080 Speaker 3: topic for the future, or just to say hello, you 920 00:52:52,120 --> 00:52:54,799 Speaker 3: can email us at contact at Stuff to Blow your 921 00:52:54,800 --> 00:53:03,240 Speaker 3: Mind dot com. 922 00:53:03,360 --> 00:53:06,319 Speaker 1: Stuff to Blow Your Mind is production of iHeartRadio for 923 00:53:06,400 --> 00:53:10,239 Speaker 1: more podcasts from iHeartRadio, visit the iHeartRadio app, Apple podcasts, 924 00:53:10,320 --> 00:53:26,680 Speaker 1: or wherever you listen to your favorite shows.