This talk and the essence of the talk really tries to get to grips with the underlying principles behind the colour around us and behind the vision that we have and the vision that we use to see that colour. Science such as physics, the interdisciplinary nature of physics with biology and chemistry, it's not dry, it's not static, it's not old, it's new, it's vibrant, it's dynamic. The central aspect of this research work is the discovery aspect. We have been able to do things and understand things and perform experiments. The first people to do those experiments ever in the world, the way that a laser light interacts with a butterfly like this and for the first time in the history of the world, we were able to see that and finally we were able to understand how the mechanism works behind that colour effect. The inner sense really summarises the essence of the thrill. It's adventurous, it means thrill seeking through science. I'm a professor of physics, a doctor of physics at Exeter University in the School of Physics. Some of you are physicists, will be physicists, some of you will be biologists, chemists possibly. All the sciences are linked and the material I'm going to talk to you about today, light essentially, will draw upon ideas and explain concepts in all three sciences, especially physics obviously, because that's what this talk really deals with. But we're going to talk about biological systems like butterflies, like beetles. We're going to talk about the chemistry of colour, of pigments. Science is one big umbrella and to really be a good scientist and to contribute to science, you've got to have a good understanding of all three sorts of sciences. So, there's a lot to talk about. I'm going to rush through things. At the end, there may be some time for questions and you're very welcome to come down and look at some of my demos too. But in the meantime, let's get on. With the first slide, let me try to grab your attention and perhaps you can tell me what is wrong with this image, apart from it being Brittany. Well, let me give you the answer if that was a rhetorical question. Let me give you the answer. The answer is, she's got hair. Okay, that's a kind of pure art answer, that's a cheeky answer. So let's get on to the science. You might look at that and think, that's not science, really. What's he doing showing us a Brittany Spears picture? Well, this actually comes from a science website, Brittany's Guide to Physics. And there's the URL, if you're interested, it actually explains how lasers work in a really clear way, bizarrely. But let me stop you from looking at her. Don't look at Brittany. What's left? Well, what's left is the background behind her. Look at that background. If I were to set you an exam right here and now and say, describe the background, the sort of words I'd be awarding full marks for would be regular, periodic, geometrical. In other words, the holes that you see in that background are regularly spaced from each other. Now, here's the thing. This is a lecture about light, isn't it? About light and color. Here's the link. The link is, if we as scientists could make this, but make the holes very, very small, make them nano-sized apart from each other, then that background would control light. It would manipulate light. And believe me, and I'm going to try to convince you about this today in this lecture, believe me, that is going to affect and is affecting already all our lives. So without further ado, let's get on and do some demos and explain some science. We've got to start with some background. And the background might be is, we've got all this white light behind us. We've got some white light on the side here. We get white light equivalently from the sun. Where do all the colors come from?  You know the answer already, but let's just revise it in case maybe you were asleep in that lesson. So, how do you separate colors? Well, Newton did this fascinating experiment. He did, took this big glass block similar to this, okay, similar in size, in fact. And he went to his window in the sunny countryside way back in the 17th century. And he went over here and there was a shaft of sunlight coming through his window. He put the prism right on the shaft and it's not very bright outside. And this hole is a bit too big.  And that shaft of sunlight that came through the window went through the prism and the white sunlight, all the colors in that white sunlight separated as they came out through the prism. So, let me dim the lights. Over here we've got all the colors that you recognize. We've got the reds, the greens, the oranges, the blues, the violets. Let me point to a color and you can tell me what that color is. Absolutely right. Well done. Orange, yellow, difficult. Let's try this one. Okay, violet. Yeah, it's all a bit iffy, isn't it? Okay, here's a really tricky question. See how clever you are if I point to this color. Ah, some of you are really clever.  Even though I've said I'm pointing to a color and that's it. The word color. That word color, really, we understand normally in day to day speak as everything we can see across this board at the moment. But believe me, because this slide projector is producing more than just that which we can see, then there's actually more stuff up here. Let me convince you of that or let me try to convince you of that. This is a camera that I bought at a shop on the high street. It's a security camera and this camera can pick up some infrared. So, let me turn it towards the spectrum. Oh, I get out of the way as well. In fact, I'll have to come around this way. So there is the spectrum. Wow, that's really bright. Surely, that spectrum on the board isn't very bright. But when I point the camera towards it, look how bright it is. I'm actually cheating. Look what I'm going to do right now. I'm going to point this towards you guys and then I'm going to take this torch and shine it at the audience. So what we are seeing is actually infrared coming from this torch, illuminating the audience. And the camera, believe it or not, is picking up some infrared. So let's go back to the spectrum over here.  Watch where my finger is and then I'm going to point the camera here. So you can see that on the black and white screen, my finger is pointing to some bright light. Whereas here on the board, I'm pointing to black. So where my finger is right now, that is infrared. We just can't see infrared. In fact, let me show you what a serious, a really expensive infrared camera can show us. This is a movie, a very short movie of my friend Ian who works in Exeter. And one winter, in fact last winter, he got into his car and he said, hey Peter, take your infrared movie camera and film me after I've gone for a drive in the car. So that is the engine on Ian's car. Now, here's the special thing. Infrared is actually a measure or can be a measure of the heat of an object, the surface temperature of an object. So look here, that's the car of his engine. And as I start the movie, you can see Ian getting out of his car. It's a cold day. The windscreen is reflecting the ice cold sky above. And Ian's getting out of his car. And Ian hasn't got a lot of hair left. So you can see that the top of his head is losing a lot of heat. In fact, you can see his eyebrows are actually causing him to retain heat in that region. Now, biologically speaking, that's a really fascinating idea. Because that in a sense is proof, absolute proof that mammals, humans who have hair, use that hair largely, or biologically speaking, use that hair to reduce heat loss. That's why it evolved into us, into mammals in the first place. Now, over here, let's just ignore Ian for a second. Over here, we have the spectrum. Now, I've pointed to Infrared. Let me go to the other end. That clearly is violet. And who can tell me what that color is? Ultraviolet. You guys have been well taught. Congratulations to your teacher.  Could you guys over here who volunteered, the ladies, could you come down to the front and help me with this demonstration? So, ladies, if you could stand in a line just here, please. Now, what the ladies have agreed to help me with is to demonstrate ultraviolet fluorescent makeup. So let's see if this works. Now, I'm going to have to push you just to that side over there and squeeze by here. OK. So the lamps that we have here are ultraviolet lamps. Can you push back a little bit, ladies? Thank you. Can you see that the ultraviolet is making my shirt, making our shirts glow bright blue? Well, in fact, these little things right here, this is makeup that glows bright yellow or orange or blue when it's exposed to ultraviolet. So I'm just going to, in turn, put a little bit of this makeup on you, if you don't mind.  Do a little bit of this and a bit of that and a bit for you. In fact, let me put it on your hand and you can do it yourself. There you go. And you as well. So I put it right in your nose and smear it right in. Let me do it as well. Here we go. And let's try a little bit of blue as well, shall we, because this is a bit of fun. OK. Just take some of that. A bit of some of that as well there. It's right in the middle of my hand. So industry is actually making some use of this sort of makeup. The way I've applied it clearly isn't perhaps the best way. And the way these ladies who are, I'm sure, much better at applying makeup than I am, they might choose to, and you guys might choose to use this sort of makeup which uses fluorescence. Ultraviolet we can't see. So although we can see a bit of violet coming from these tubes, we can't see the ultraviolet. Now the ultraviolet that is coming from these tubes is pretty safe, so don't worry about that. Normally the UV coming from the sun is harmful, but this isn't harmful. Companies who make this hair gel and companies make this sort of makeup, they are relying on the fact that the dye in this, the pigment in this absorbs ultraviolet and changes it to yellow or to blue or to a wonderful shade of yellow and blue, and then it re-emits it. And that's why we can see these colours. Ladies, you look fantastic. Let's give them a little round of applause. OK. Can you still see all the colour in my face? Not so much. It's bizarre that.  So that is fluorescence. Now, back to this. Physics can't stand alone. Biology or chemistry can't stand alone. So let me link in the physics associated with this object, with this shot to the biology, to the evolutionary story. Can you see what we're doing here? We're jumping from pure physics, optics, light, colour to biology. There's a clear link. There's a huge link. So here it is. I've got a friend who works in the reptile house at Bristol Zoo, and he said, Peter, come up to the reptile house, bring your infrared camera, because it's an interesting thing for you to film. So I went up there and I had the camera, and here is a picture taken of me holding one of his snakes in one of these reptile enclosures, and he took this picture. Now, the picture isn't a real colour picture. It's an infrared camera. You can see infrared, obviously. So the picture translates the temperature of the surface of these objects, of my arm, of the snake, to a colour. So let's just decode that. So all the yellow of my hand is around 32, 33 degrees centigrade. That's quite warm. In fact, that is a sign of me getting pretty nervous holding this snake. And do you know why? Because he said, Brian said, this is one of the seven most deadly snakes in the world. So can you see at the far end over here?  Pretty serious stuff. The venom in that can kill a lot of people with just one bite. So let's go back to the biology. Look how hot my arm is. The physics tells us how hot my arm is. But look how cool and calm and collected the snake is. Now do you know why? Why isn't the snake as warm as I am? It's in the same room. It's at the same temperature. I know it's supposed to be cold-blooded, but that doesn't have anything to do with the surface temperature. Here's the reason. Can you see these little pits? In fact, this is why it's called a pit viper.  They detect heat, and they detect the heat of its prey. So can you see what's going on here? It thinks that my arm is food. And it is cool and calm because it does not want its body heat to get in the way of it detecting its prey. So that's evolution. If its surface temperature was the same as my arm, if it was yellow under this infrared camera, then it would not be able to detect prey in the same sort of way. Its body temperature would get in the way. So that's evolution. That's called an evolutionary adaptation. And it's really important. We've all got adaptations in ourselves. All the animals in the world have got to where they are today because of their adaptations to evolutionary pressures. So suddenly we're in genetics and biology and evolution, and yet it should be a physics conference. Let's drag it back to physics, shall we? It's all very well, you know? Talking about light and colour, and that's a fascinating field. But to really appreciate it, we have actually got to understand how our eyes see. Here's a fairly cheap model, but nonetheless useful model of a typical human eye. The red sections are cutaway representations of muscle, which move the eye up and down and left and right. So when I take this off, like this, and I'll just put this down, the first thing that I see at the front of the eye is the pupil. The pupil is actually just a hole. And it's a hole, again, which is a wonderful biological adaptation. The hole, as many of you know, the pupil changes size. Let me show you a picture of my three-year-old son's eye. His name is Luke. Luke is three, and I had to persuade him to sit at the desk in my office for me to take this super-close-up picture by feeding him loads of Maltesers. That's kind of bribery. But that eye. In fact, do you know the reason why that iris, why our pupil changes size? About two years ago, I was playing basketball and I got an elbow just accidentally on the side of my head. I was really hurt and my eyesight started to go. So I went to the eye hospital and the doctor said, just sit down. I want to look at your retina at the back. Do you know what the retina is? The retina, once you take the lens out and the glob will fluid out, the retina is what's at the back of the eye. Let me show you a schematic of the retina. There it is, right at the back of the eye here. That's where the light comes through and hits the cells. And our cells, our living cells at the back of our eye, they detect light. So this doctor said, I need to look through your iris, through your pupil and see whether there's any damage. So she said, well, at the moment we're in a dark room. So your pupil has shrunk. I need to add a chemical to your eye that makes it dilate. And she did. And she had a look and after half an hour, everything was fine.  So I went outside and it was a bright summer day and guess what? The chemical was still in my eye. So my eye, my pupil was huge. And I went out and it was bright summer day and it was like someone was hitting me in the eye, someone was putting needles in my eye. The intense light hurt my cells at the back that much. Automatically, if there was no chemical in my eye, my pupil would shrink right down and it would reduce the number of photons, the amount of light coming in. And so it would stop damage in our eye. Now I know many of you have seen this already, but let's do a little test. What I'm going to do in one second is turn the lights right off and then I'll get each of you to look at your nearest partner, your nearest neighbor, really close. And as I turn the lights on, just check out how quickly and how much the pupil gets big again. Can you choose your neighbor? Let's do that. Do you know what that is? That is a biological adaptation. If there are biology, if the way that we evolved, our eyes evolved as humans, if it didn't happen, then our eyes would be limited or we'd damage our eyes much more easily. So once again, we're talking about biology and yet this is a physics lecture. Remember, science is totally interdisciplinary. So, those cells I was talking about, what do they look like? Well, sometimes people donate parts of their body, organs, brains, hearts, eyes to medical research. And this is a picture taken from a lady who donated one of her eyes to medical research. And this is an electron microscope picture of the cells, the living cells at the back of her eye which detect light. Now, it's the lens at the front of the eye which is responsible for focusing light onto those cells, but it's the cells which pick up the light and which change the light energy, the radiant energy into little electrical signals that feed into our brain and our brain then decodes them. So, we've got two sorts of cells, big rods and the rods are responsible for us being able to see at night time under low levels of light, but the color discrimination that we all have, that most of us have, is due to the presence of cones. Now, again at Bristol, a friend of mine works at the vision department there and he says, come up, I've got lots of contacts. He said, come up and let me take a picture of your cones through your retina.  You've got to use a special camera and a special setup. So, this is what my cones look like. You've guessed it. We see using three different types of cones, cones which are sensitive to red, to green and to blue. In other words, the primary colors of science. Now, art, a lot of you may be artists and doing art, GCSE and art A level and that's fine and that's great for science, but artistic primary colors use a different set compared to scientific primary colors. So, here we go. Three primary colors, three color photoreceptors. Receptors, receivers of photons and photons are particles of light. Now, what happens, here's a big question, what happens if genetically we have inherited a gene which has a little tweak on it, which is slightly different and what happens causes us to maybe have a different sort of photoreceptor, here. The answer is, you see color in a different way. Now, the traditional name for that sort of condition is color blindness, but I have to say right now no one is blind unless it's a really serious form of that condition, but someone who has a different color genetic workup of their photoreceptors, they are not blind. They just see the world in a slightly different color light. Now, some of you may have this color alternative version of the world, let's see who has, maybe. This is a really simple eye test. Please don't shout out. Please don't shout out, but can you see, can you identify the three color shapes? Don't shout out. You chaps up there. Okay, let me give it away. So, right here. My eyes are not perfect. Don't get me wrong, okay? So, that is a kind of mustardy yellow square. Everyone see it? Good man. That is an orangey creamy brown. Well, it should be a circle. Fine, everyone see it? Good stuff. Okay, just in here, and again, my eyes aren't proper perfect. In here is a kind of slight bluey-greeny vertex of a triangle coming down, just skirt in the top of that line to about here. You can see that? Can you see it? Because I've got a... You've got super woman vision. Fantastic, because I'm just making that up. Okay, that was just a little trick. Now, there are only two objects. Only two objects. But, this is a silly test, because it's not a proper test. It's not a proper recognized medical optical test. Those tests are called the Ishihara tests, and they're named after a Japanese professor of color vision way back at the turn of the previous century, who came up with standards. You shouldn't just recognize squares or circles or shapes of objects. You've got to recognize, generally, be able to recognize or differentiate numbers or letters. Now, here's the proper test. Don't shout out the number. That's a two or a five. Don't shout out. That's a 29 or a 70. That's a 74 or a 21, and that's an eight or a three. Now, many people with color standard vision will be able to distinguish both numbers, either number. But some people who have a color alternative sort of vision can only distinguish one. So, for instance, most people here, who can distinguish a five? Well done. Up here, who can distinguish a 70? Good, because it's a 29. Who can distinguish here a 21? I can sort of see a 21. There's a sort of bottom of the two. There's a one here. But the proper number for color standard, the dominant number would be 74. And over here, again, it's an eight. So there may be some of you who can only see one and perhaps you're a bit shy to put your hand up. It does not affect your life, except in a really extreme medical case, and you probably wouldn't be here if it was that extreme. Color alternative vision is just something that your brain adapts to, and it doesn't make you any better. It doesn't make you equip you with better eyes or worse eyes. It just allows you, in fact, to see the color in a unique way, slightly different to other people. Now, genetically, here we go with biology again. Genetically, get this. One in 10 men have color alternative vision, but one in 250 women have color alternative vision. Now, what's that all about? To answer that question, you've got to turn to genetics. You've got to realize that this color alternative vision is due to a specific tweak on a gene within the X chromosome. Men are XY, women are XX, so if a man inherits from his maternal side an X chromosome that has that color alternative tweak, he will definitely be color alternative. But if a woman inherits a color alternative X, she may also have her second X, because she's XX, will be color standard, and that's usually the dominant gene. And so her, she will be a carrier of this color alternative vision. Now, we're going on rabbit and on. We're going on a biology again. It's such an interdisciplinary subject. Let's get back on track. How do we produce color? Now, I've shown you that if we use one of these things right here, a prism, we can separate the color from white light. Great, okay, that's a classic experiment. But my hair, well, my hair used to be really dark. I used to be really proud of it. But it's gray now. Your hair or skin or eyes, whether it's dark or light, that depends on something inside it called melanin. It's a pigment. Some people have red hair. That's due to a different pigment. My gray hair is because I don't have very much dark pigment, melanin in my hair anymore, okay? So melanin is a pigment. One of the ways of producing color, this first way, is a pigmentary color through dyes or through pigments. And we could go into the chemistry of this. Suddenly, we're on to chemistry, okay? What is this? We won't go into a lot of detail. The chemistry relies on a molecule.  What is the name of this molecule? Let me give you a clue. Remember, we're talking about color. What color, what molecule, what pigment is responsible for that green right there? Chlorophyll. Well done, that was a unanimous chlorophyll from all three sections. Fantastic. We have three pigments like melanin. In fact, let me show you what chlorophyll looks like color-wise. So we have three pigments there. The green one is chlorophyll that I've extracted from the top of some organic carrots from the sort of leaves of organic carrots, okay? And that extraction is quite difficult, but it's possible. Chlorophyll is green because, well, let's see why it's green. Why is chlorophyll green? When we shine white light at it, now, up here, I am representing white light, sunlight, if you like, as a combination of three primaries, so red, green and blue. What happens to the red and the blue? That's the real question. The question isn't just, okay, why is green reflected or scattered or whatever word you want to use. The real question is what happens to the red and the blue? Does anyone know the answer? It's absorbed. Wow, your teachers must be fantastic. It's absorbed. It's absorbed. So pigments work through absorption. Let's talk about the other pigments. That's chlorophyll. That is blueberry juice. And that, well, I could be really disgusting. And I could say, you know, I used to have a little dog and unfortunately she died. But before she died, I was able to take some blood out of her. And that's not true. Right now, that's not true. But that word, blood, normally we associate blood with a living process, with life. Because blood takes oxygen from our lungs and distributes it to our cells. Now, that could easily be blood. It is not. Because blood, the name of red blood, is oxygenated hemoglobin. That is just a pigment. Even though it's vital for our lives, for life, it is just a pigment. Now, let's see. Do you know what vegetable it's from? Beetroot. That's beetroot juice. Again, it's just a pigment. Now, here's the thing that I really want to demonstrate. This is the real physics, the biochemistry and physics of it all. How do these things work? What do we get when we color mix? Many of you might be artists and you might do art all the time and you mix your pigments and mix your paints. What happens when you mix green with red or blue with red? When you work by absorption, then a funny thing happens. Let's see, shall we? Green is green because it absorbs red and blue. Red is red because it absorbs green and blue. Keep up with me. Blue is blue because it absorbs red and green. Red and green. That absorption is going everywhere. So if I mix all three primary pigments together, primary pigments, then the absorptions will all cross over and overlap and everything should absorb everything. Shall we see if that's the case? What happens to light if everything is absorbed? What have we got left with? Black. So let's do that. And there it is. That's pretty black to me. Remember, that is black. Pigments mix in a color subtractive way because of the absorption color is subtracted out of the overall effect. And that's an important thing to remember. Really important. Okay, let's move back. Lies and absorption. There we go. So the second way, and this is the really important way, guys, I know we've probably spent half the lecture already talking about pigments, talking about things which are interesting but are not really fascinating. Let me try to really fascinate you now if I can. And I can tell all of you are seriously fascinated already and I'm gratified to see that. Okay, soap bubbles. Soap bubbles. You smell like a clean audience, which means you take showers very frequently and it's great. And when you take showers, you use soap. And when you use soap under water or with water, you get bubbles. And soap bubbles just like that. Soap bubbles are colored. If you look closely enough, if you put a black background behind them and illuminate them with some sort of white light, you will get some wonderful, deep, saturated colors just like that. But you've got to look carefully. Okay, you've got to look really carefully. Now, soap solution. Even if it's, even if fairy liquid is a little bit green, I know it's green when it's right in the bottle, but when you dilute it down, it's transparent. How on earth are we getting all of these beautiful, deep, deep colors out of something which has no pigment in it, which is not colored? Which is really not very far away from water. That's what we have to investigate, okay? There is a mechanism responsible for that. And that mechanism produces the colors in all of these types of animals. It's not structural color because it's the structure of the thing. It's the thickness of the layers which create the right conditions for bright colors. Now, let me show you some of those colors. Here's a picture at our local lake that my five-year-old daughter took. Lovely ducks. And here's a peacock. You all recognize that the blue that we see here is a bright, bright blue. It's a much brighter blue than you will ever get from pigments. But it's incomparable compared to this sort of blue feather. It's amazing color. In fact, let's just show you some of the color in one of these butterflies. If I flick through to all these different plants and beetles and butterflies, let me show you this. Do you see that butterfly? Now that has no blue pigment in it whatsoever. All of these colors that we see here, the greens, the the greens, the blues here, the little blue spots, all of those colors do not have blue pigment or green pigment in them. They're produced in the same way that the color of soap films produce color. Can you see the clown's face on here, by the way? Have a really close look. Let me keep asking the question. Can you see the clown's face? That's a clown beetle. The real question is, in terms of physics, and remember, we're back on the physics track now, in terms of physics, what on earth is going on? What is the underlying principle that produces that color? We're going to have to show you a picture, and then we'll do a demonstration right here. There's the picture. On the left, we have two waves which have their peaks overlying, one peak on top of another, and when you add them together, they produce a super peak. But when on the right, you displace, you move one peak a little bit so that it's overlying a trough, then you get cancellation, the condition, the mechanism is called interference. That's a word you'll have to know at A-levels, definitely. And it can be constructive or it can be a super wave or a super peak, or it can be destructed. Aaron, may I ask for your help if you can stand there? Ben, may I ask for your help? Can you stand over there? What we're going to do is demonstrate that. Give the boys a little round of applause for coming down. Right, Ben, if you can hold that in pretty tightly. Go right as far as you can over there. Actually, come forward and hold just before the knot. That's it. Aaron, go right back, go right back. Go as far as you can slightly to your right and back a little bit further. Back a little bit further, please, Ben. Perfect. Now this thing could be a skipping rope. We could get a skipping rope thing going, but what we're going to use it to represent is light. Is light travelling between two places? So over here, on Aaron's hand, I'm going to send a pulse of light, a light wave down this medium towards Ben. Watch this. Actually, go right back to the seat. Fantastic. So here is the light pulse. Now tell me, everyone, look closely. Tell me what happens when the light wave meets Ben's hand. So here's my pulse. I'm winding up. What happens when it meets Ben's hand? It reflects absolutely. Now what I could do is instead of sending just one pulse down, I could keep going. I could keep tweaking it at a constant frequency. And what you will see is that the wave going down here will meet the wave that went before it that's coming back. So we've got two waves. We have the addition of waves. Now if we get it right, if we get that repetition rate, that repetition frequency right, then the peak of the wave coming down might meet the peak of the next wave coming back and what we have is two peaks or two troughs adding right in the middle. Aaron, can you just sort of tweak your hand regularly? Little bit more slowly. Exactly like that. Keep it going. Now this might look like a skipping rope. Bit more energy. Well, bit more energy. Excellent. Excellent. Raise your hands up a little bit. Bit more energy. Now that might look like a skipping rope but what you are witnessing is interference. The peak going here is constructively interfering with the peak that's coming back. Excellent. Now we're going to stop you there. Let's try to get destructive interference right here in the middle. You keep your hand still Aaron. Ben, I'm going to ask you to do it. Can you waggle your hand slightly faster than that which Aaron used?  Kick in with a fast one straight away. Sometimes you fall into the same frequency.  Can you do that? It's tricky. It is really tricky. Actually if we go in a circle then it's a bit easier in a circle. This is so hard. I'll tell you what, go as fast as you can. Ben is doing a great job here. Can you all see that occasionally we're getting zero displacement in places? Right here, there's a zero displacement. That means there's destructive interference going on in this place. Big one. Can we please give these fine gentlemen a round of applause? Thank you Ben. Cheers Aaron. That in a way is how colour is produced but let's really see how colour is produced. What we need is a film or a little structure. Here's our structure like a soap film and we shine white light down on this soap film. That's what we have to have. It comes down at a particular angle. It can be a straight on or it can be a large angle. Let's vary that in a minute. Now when we get a reflection from the top we also get a reflection from the bottom and suddenly this is the important bit. Suddenly we've got two waves of light. And do you remember what light waves do? They can add together destructively or constructively. Remember, the angle is really important. Now let me show you exactly how important the angle is. Here's a little movie. What colour is the car? Have a look at the side of the car right here. What colour is it? Red. Pink. Red. Pink. What colour is it? Keep archery. Keep archery. More, more. What colour is it? What colour is it? So if you're driving this car and let's say you go a little bit too fast or you're kind of you're wavering. Let's say a policeman stops you and the policeman says, is this your car, sir? Or about it? And you say, yeah, you love it. And then he or she will say what colour is it? Well, it was pink. The answer is, the correct answer is it depends on the angle officer. Because, because as you saw, the colour changes and that is the definition of an iridescent colour. Now you can't get an iridescent colour through melanin or chlorophyll or cyanine or anything like that. You can only get it when you use tiny little structures to create the colours. So, butterflies have been doing that for a long time. And as scientists, we studied this butterfly and about eight years ago we sat down at the desk, a few of us at Exis and we thought, we're physicists. Let's ask a proper physics question. How is the blue produced? Some of you might do an experiment like that and your teachers might say, tell me how this is done and you've got to do a measurement. So we did all our measurements and then like proper scientists, we try to be proper scientists, guess what we had to do? We had to write our results up into a report, an experimental write-up and we put a title, an introduction, a methods, a result, a discussion, a references and then we published it. And here are some of the things that we discovered. Let me show you. When we looked at the wing using an optical microscope, we saw all these things. And in fact what I've done is I've brought an optical microscope here and it's a bit of a low-tech one but nonetheless we should still be able to see the images from it. Now I'm going to have to dim the lights for this. Temporarily there they are. There are the butterfly scales that we saw about eight years ago. So if I can focus a bit or move them around a bit they're out of focus, let me focus them up. There is a scale. There's a scale right there. There are lots of other scales. This is a region where the scales are missing. And that's exactly what we saw when we did this experiment a few years ago. But that's not enough. That is absolutely not enough because you have to look with more detail and to do that we need an electron microscope. So now we've got some images taken using the electron microscope. And these microscopes are great. They're fantastic. They don't use light because sometimes it limits the detail that you can see. You can only get to a certain magnification using a light microscope. Whereas with electrons you can get really massive magnification. So that's a good magnification. That line there is one millimeter. So think on your finger how big one millimeter is. And then think even further how big one of these scales are. There's one scale. And when we look in a lot of detail at the scale look what we see. These parallel lines up and down but also you've got to have a really careful physicist-scientist eye on. Have a look just in here.  And it is those layers which are responsible for creating this blue reflection. Without that it wouldn't be blue. Now we published, we wrote that up and we published it in a journal. And then that journal went all over the world in the normal way. Not necessarily anything special but it was just in a normal way. People can read that. Guess who read it? L'Oreal read it. The L'Oreal Cosmetics labs the scientific labs in Paris read that. And so they gave me a call and they said come over and present your work to our scientists because it's the idea of being able to produce color without pigments and applying that to makeup that we want to try to use. And that's the nature and apply it to our technology. And so they made some makeup. They made some photonic cosmetics. That word photonic again, it's a special word it involves using light using photons of light. So there is some lipstick. It's got no red pigment or no blue pigment in it but that blue sheen is the result of an iridescent effect just like the car body. Now when we zoom in and see these big huge lips right there you might think oh that's a bit garish that's too much for me. Maybe Western Europe isn't ready enough isn't ready yet for that. You'd be right maybe. It's not fashionable here yet. In fact if you look at anything that close up on someone's body it doesn't look all that appealing. But when you take a step back and look at the model admittedly she's an attractive lady but when you look at the model professionally made up the look, the makeup is a very demure very elegant look to it. I wish some of the inspiration was taken and there's me on the side a L'Oreal model or as close to one as I'll ever get. So there is an application of some of these ideas. A group of scientists admittedly from Exeter, from us at Exeter we studied this natural system and we applied those ideas and we helped other people apply them to technology, to industry. Let me jump ship now to turn the subject around. It's not blue, it's now green and we're actually not going to talk about a butterfly for two more minutes until we talk about neo-impressionism. Who painted that picture? Sura. Who can tell me this? What is special about that painting? God. Dots, absolutely. Do you know what other kind of really posh word we use to describe painting with dots? Points. They're dots, they're points of mentalism. In fact, this picture is made up of tens of thousands, hundreds of thousands of microscopic little dots. So this artist, this is a huge picture in this artist, you know what he did? He had the big canvas in front of him and all he did was just get a tiny little brush sharpen the end, dip it into a colour dotted on the board dip it into the colour dotted on the board for eight years. But it's worth. I don't know how much it's worth now, but it's a fantastic piece. Now, you can't really see all the tiny dots because they're so small but let me show you the effect. Here's the effect. That's like a normal picture. You can sort of see some dots but let's zoom in. Suddenly, you can see now that all the yellow region is made up of dots. All of this region down here, they're tiny little dots of colour, different colours. Now, why? That's a good question. Why on earth did he choose to do that? Well, here's the reason. We've got a different sort of colour audition. Colour addition. Anjali, can I ask you just to step up to the control box over there? Now, what this young lady is going to help me do is to turn on some coloured lights. Let me turn the main lights off. So, first of all, could you flick on red temporarily and then blue and then green? Red, red off. Blue or green on. And then the last one, please. What we're going to do is we're going to add big dots of colour. These dots are now massive. All three on at the same time, please. Suddenly, we are now mixing projected colours. Look at this. So now when all three primary colours, red, green and blue, overlap in the middle, we've got white.  That's not a good white. That's not a proper white. Look at it. It's a sort of ready white. And you'd be right. You'd be absolutely right. So what we're going to do, because it's a ready white, we're going to turn down red a little bit. Could you do that, please, Anjali? Just turn down red ever so slightly. Turn it off, actually.  Bring it up. Keep going, keep going, keep going, keep going, keep going, keep going. Stop. That looks like a slightly better red. So what we're getting at is if you mix colours, projected colours in the right intensities, you can get any colour you like. How do we get black this way? That's right. Turn all the colours off. Please turn them off if you would. And let's give our wonderful assistant a little round of applause right there. Thank you very much. So, you might think I've never seen this before, but you have. You've seen it every single day, probably of your lives, except maybe one or two days on holiday when you work near a colour television. Colour televisions produce all their gamut of colours, their range of colours by mixing three primary colours. Your colour mobile phones are colour game consoles. They mix little pixels, little points of colour for all three different colours. That colour mixing is different. We call that additive colour mixing. It works in a different way to the subtractive colour mixing. The mixing by absorption that we've got here. And that's, you've got to bear that in mind when you think about art, when you think about science. They're very different in those two different addition systems. So, why on earth did we talk about that? Well, let me show you why. Here's a beautiful butterfly right here. This is a Papilio butterfly. And let's run the movie. There it is. This is my favourite butterfly of all time. That green, biologically speaking, that green is a camouflage green. So it has evolved the green in order to camouflage itself against the leaves on which it sits and on which it lays eggs. But how is the green produced? Well, when we take a picture of it, let's take a big picture of it. There it is.  Normal sorts of scales. Now I said that this microscope here is a little bit iffy, but nonetheless it will still give us an indication about what colour the scales look. We expect them to look green, don't we? Let's turn the lights off and let's go back over here to have a look at the Papilio butterfly. What I'd like to ask you is where is the green? Now this is a green butterfly. But where is the green? All I can see and I think all that you can see is lots of yellow and in between the yellow there's lots of blue. When you take a picture using a proper advanced microscope, guess what we see? This is what we see. That is the colour that we see. It's a mixture of blues and yellows. And do you know what colour we get when we mix blues and yellows? We get green. So in other words this butterfly has evolved the ability to make green using two different colours. It uses that pointillism that pointillistic colour mixing effect and it invented it it evolved it 50 million years ago and that French guy who invented as it were neo-impressionism he invented his painting technique around 100 or so years ago. Figure that. We're actually using these ideas. We did this experiment and we published these results and guess who decided to use it? Well the anti-counterfeiting industry is in the process of using these ideas. Every single year this is a fact. Every single year the people who make anti-counterfeiting logos on credit cards or on banknotes or on theatre tickets or on software packaging they are only six months ahead of the counterfeiters. So the industry is always looking for ways to make logos, ways to make complicated colourful logos that are really hard to replicate and reproduce and believe it or not the ideas that we and others have discovered in this butterfly are being used, are being mimicked. We don't, these butterflies aren't killed and then put in the credit cards. No, the ideas are being used. That's the important thing. All world ideas are being copied. So we've got a couple of examples already. Now we've just got a few more slides and then the lecture is nearly over but we've got one amazing bit of physics and an amazing application to come. This will affect all of our futures in the next 15 or 20 years. Let me try to introduce it. 3D photonic structures that's a fancy complicated phrase. 3D stands for three dimensions. Let me show you a three-dimensional object. Well, everything, all of us are three-dimensional obviously but let me break it down a bit. These are three-dimensional models of chemical crystals, of crystals. This is a model, it's a cubic 3D model of sodium chloride with the green atoms representing sodium ions and the gold atoms or spheres representing chlorine atoms. This is a different sort of 3D model that represents diamond. It's a tetrahedral structure and each black sphere represents a carbon atom. Now, whatever way I turn it, it's three-dimensional. It offers a different surface to us. Here's an amazing thing. Have a look at this beetle or at these beetles right here. Bearing in mind what I've said about that 3D set of structures, have a look at this. There are some wonderful friends of mine and you saw a few on the desk on the visualizer right here. That blue one is in particular very interesting. Let's examine it. Let's do our normal set of physics analysis experiments on it. That involves using an optical microscope and an electron microscope and lots of other things, of course. So let me show you the electron microscope images. Here is one image of a scale, a region of the wing. So there's, we're taking a region of the wing just here. There. These are like our hairs. In fact you can see some longer hairs there. If we plucked out one of our hairs from our heads and had a look at it, it would have a root and that root sits in our scalp. These scales each have a root. You can just see the root right there and that sits in the wing substrate of the beetle. Let's zoom in. There is one scale. Now, there's no scale bar on that picture but let me put it into context. This is amazing. This is so small. If we had this in our finger we wouldn't see it with our eye microscope or a magnifying glass. If I plucked out one of the hairs in my head and cut the end off so that the end was actually a circle and then if I put that end in the electron microscope just like that one, well, one end of its diameter of my hair would start here and the other end would keep going way over to about there. About the end of that bar right there. That's how big this is relative to a hair in our head. So let's keep having a look. Let's examine. Let's be proper scientists. Let's examine what's inside. What we did then is we broke open half of that scale to see what was producing this blue color and lo and behold when we zoomed in we saw that it was a three dimensional structure. In other words the beetle right here the beetle scale has evolved this type of structure but the size between the spheres between the points in the three dimensional structure is exactly the right size to create a blue reflection. To manipulate blue light. That's what we're doing. That's what the beetle is doing. It is controlling and manipulating color. Now imagine if we copied this three dimensional structure. If we copied it in three dimensions guess what we could do. We, you would have the ability to create light completely in all directions. In that direction. In that direction. In that direction. In all three dimensions. And that is actually vitally important. You might think okay fair enough. Cosmetics. Not very useful to the world. You might think car paint. House paint. Not very useful to the world. You might think paper. You might think fashion fabrics. In fact I've got some fashion fabric over here that you might like to have a look at a little bit later on. It's a mimic of the butterfly and it's a wonderful blue color material. Not very useful for the world. You might say. But I'll tell you what is useful. Being able to manipulate light in all three dimensions. Using these sorts of three dimensional structures leads to a potential application in computers. So here is my old computer. Here is one of the processing tools from the old computer. There. And in fact let me put it on the visualizer. There is a processor. Light on. That processor is one of the processors that does all the work. When you play your games. When you do your web surfing. When you write your projects up. When you search for images. It's that processor amongst others which is really doing the crunching. Doing the processing. But it's slow. The reason. The reasons you might know and you might understand. Let's have a look. If we have a look at one of those chips. Put it on our finger. And then if we prize open the top of the chip. Guess what we see inside. We see this. Array. This complex jungle of electrical components and wires. Now the electrical components are the physics of them. The science of them is really complicated. But it's well known. But they're resistors, capacitors, transistors. Lots of things which allow signals to go from one transistor to another. To do the processing. To do the networking of communication really. But the main content of that chip. Of that board is this. Let's zoom in. There it is. It's wires. There are hundreds of thousands of wires on this region right here. What's the problem with electrical wires? Let me tell you. Let me tell you the problem with electrical wires. They have resistance. You know about electrical resistance. You know about Ohm's law possibly. When you put an electrical current. When you try to flow electrons through a wire. The electrons make the wire heat up. So the electrical energy you use to do that part of it is converted into heat and it's wasted. So the computers get hot. The chips have to be cooled. That's a huge waste of energy of natural resources. Not good. But worse than that. Worse than that is the fact that electric current. Even if it's the electric current in these processor wires. It travels really slowly. Now it's far faster. If you stand at the edge of a room and flick a switch to turn the lights on. The lights come on within milliseconds and you might think wow. That's fast. But really in the grand scheme of things it's not fast at all. It's really slow. What is? Tell me this everyone. What's the fastest thing in the universe? The speed of light. Light traveling from one point to another point. With no air or no solid or no glass in between. Just vacuum. Just space. That light travels at the fastest speed. Now even if light travels through air. That's still pretty fast. So get this. What if we take away the electrical wires. And we replace them with light wires. I'm not talking about optical fibres. We've moved on a little bit from those. Even though those are sort of light wires. We're talking about something else. We're talking about photonic crystals. Crystals just like this that the beetle has shown us. Either in three dimensions or in two dimensions. Which allow us to manipulate light to send communication signals back and forward between transistors within processing chips. That will completely revolutionise computer processing. Communication. Signal processing. And that will happen in the next 15 or 20 years. So guys in the States and this is from Boston. From MIT I believe. Guys are modelling these things. Before you build things like this. You have to demonstrate that they work using computer models. So do you remember that background behind Brittany right at the beginning. That I said was useful. That I said if you make it the right way. Would manipulate light. Well here it is. And there is a little area where the holes have been removed. And when you press your button or when you hit the return key on your future computer. That will set a few light signals going. In lasers. In light emitting diodes. And those lasers will communicate from one place to another place via a light path. A light guide. So let's press that button. Watch me. We're going to press the button. Up here. And the laser will fire. And there is the light. Going around corners. And it's travelling around corners via this effect called interference. It's a lot more complicated a system. Now it's like a two dimensional or a three dimensional type of system. But light can go around corners. And up or down or across or backwards or forwards. Any way you want it. If you can control. And if you can manipulate light. Now it's not just the natural world like beetles and animals that are teaching us how to do that. Scientists, you know male professors, female professors, all these technicians, all these post docs and post grads. Men and women.  Previously physics was limited to male and sort of stuffy but now some dynamic and bright young women are enthused and are pursuing these goals. It's a noble goal applying the ideas of natural systems to the physical, to the real world, to the industrial or technological world. Now okay, that's come to the end of my diatribe. But let me leave you with this movie.  Maybe there's more to it than meets the eye. If I could somehow magnify my insight into its internal structure what would I see? In the bottom right is the magnification. Look a butterfly. This one comes from Madagascar. Its bright colouring is as much a call for attention as a warning. It follows the weather changing along with the lighting responding in time to both shadows and light. It's iridescent. As we move closer the features that give it this characteristic are unraveled. On the surface of the wing we can see two layers of folds. Light and fragile looking it's hard to imagine that they're indispensable to the flight of a butterfly. Underneath the folds which cover each wing are black. Their colour is due to melanin a pigment responsible in the human body for the suntan and the colour of the hair. The black coat emphasises the contrast with the top layer enabling the iridescent folds to stand out in the dark background. There's no pigment in these coloured folds though they have no specific colour. Actually there can be any colour depending on the angle from which they're lit or looked at. When going through the folds the light is decomposed. When reflected back to our eyes it's iridescent of all the colours of the rainbow. Magnified 2,000 times here is the reason for the iridescence. This white braid constitutes the broken edge of a fold. A membrane a black and grey plaque visible underneath. Appearing in grey is chitin a series of long sugar chains. What we see in black is only air an empty layer of air. This provides rigidity, lightness and colour to the whole structure. The rays of light going through this system are much of the structure's inner walls and intertwine as they would on a soap bubble. They send back those iridescent colours characteristic of the wing of a butterfly. Our microscope has now unfortunately reached its limits. Beyond this nothing more is visible for the moment. So this has been light fantastic and you've been a great audience. Thank you.


It's one o'clock on Tuesday, March the 15th, 2022, so you must be watching Science at Soast. I'm your host, Pete McGinnis-Mart. Every week, we bring you young scientists from the School of Ocean, Earth, Science and Technology, streaming live on Zoom from beautiful downtown Honolulu. We try to focus on research that our young scientists are conducting, partly to show the excitement that is there in their research, but also the relevance that they have to here in the Hawaii community. And today, we have a really special guest, Fernanda Hendricks, is a researcher at the Schools Department of Oceanography. Fernanda, welcome. It's great to have you on the show. I understand you've recently been promoted from a post-doc position. So can you tell us what exactly your role is at the university right now? Yeah, sure. And yeah, first, thanks for having me here. It's very exciting. Yeah, I'm a researcher, research oceanographer at Soast and at Seymour here at the Center for Marine Recovery Oceanography and Research and Education. I do research in the ocean here around Hawaii. So, and I'm an oceanographer through and through. So I have been an oceanographer since undergrad and then went to grad school to be an oceanographer, then did post-doctoral studies in oceanography. And now I am a researcher in oceanography. So it's through and through. And your degrees, were they acquired at Manoa? Or have you come here from the mainland? Yeah, no. So I'm from Brazil. I live most of my life there. I did my undergraduate degree there in oceanography. I did a master's degree in Europe. So I've been traveling a bit. And then from my PhD, I came to the United States. I was in California for maybe eight years, maybe six years. And I've been here in Hawaii for the last four years. Oh, terrific. While you're surrounded by ocean, several thousand kilometers in all directions. So is Hawaii a good place to be an oceanographer? I mean, it's excellent. It's why I wanted to come here. This is a perfect place to be an oceanographer. Like you said, ocean all around. And we have the beautiful Hawaii Ocean Time series here just north of Honolulu. So it's really perfect as in terms of access to the sea. It's something as oceanographers we all strive for is to try to get to the sea and obtain information. So yeah, it's an excellent place. Great. And we heard Nick Olm on the show a few weeks ago. He was talking about ocean color. And he just hinted at today's topic, which is underwater drones. So I understand that you use this hardware on a regular basis for your kind of study. Maybe you can start off, Michael, can you show us slide one? And Fernanda, what is an underwater drone? Or how do you use them? Yeah, so like I said, oceanography relies on data. You know, we need to know information about the ocean. And there are several ways to obtain information from the ocean. And the most common way is to get a ship.  But that's very costly. It takes a long time. It's very slow. So recently now there are all these underwater vehicles. They're unmanned and they are autonomous. So which means that they can go out to sea without a person, you know, and they collect a lot of the same data that we can collect from ships. So they are these big instruments. They are this little yellow one in the middle there, for instance, is an underwater glider. You can point out a little yellow one. It's a little torpedo shaped instrument and it has all these sensors attached to it. And you can deploy it from the coast or you can deploy it from a small boat. And this glider can stay in the water for months at a time collecting data. So you don't have to be present in the ocean to collect that data. So it's very exciting to be able to have those instruments to help us out and collect more information about the ocean for us. Sure. And when you talk about collecting data, can you give us a few examples of what measurements might be made? Yeah. If you talk to any oceanographer, the two main things you're ever going to collect is temperature and salinity. So how warm, how cold the water is, where, and how salty that water is. So those are the two very basic parameters. But these instruments are very sophisticated and they have all different types of sensors that you can measure. So you can measure oxygen concentrations, so how much oxygen is produced by the algae in the water. Or you can measure how many nutrients are in the water that are necessary for algae to grow. Or you can measure how much sediment is in the water. So there's all different types of instruments that you can attach to these amen vehicles to collect information. Okay. And all of these measurements, do they record them on a flash drive or do you get data in real time? Yeah. It's a beautiful thing. So most of these instruments that are autonomous, they can give us data through satellite. So you don't have to recover these instruments. You don't have to have a little drive inside them. So here you're looking at, yeah, the first one here, you're looking at a profiling float, which is another type of these underwater vehicles. So this is a profiling float. It is that it's two, it's about, you know, five feet long. And it profiles like the name says, it goes from the surface to about 2000 meters depth, sometimes deeper. So that's, I don't know your feet, but that's very, very deep. Sorry, I do everything in metrics. That's about 10,000 feet. So yeah. Yeah. And then whenever he comes back to the surface and as the little first drawing was showing there, it can send the data through a satellite. So it's like a phone, you know, phone connection. And then he sends all that information and he can download that from your computer. So every, you know, for, for, for most floats every 10 days or so, you will get a whole new profile of data and you can just access from wherever you are. So another beautiful thing about these instruments that you don't have to go out to see to get the data, they come to you. And then I think the third slide will show a slightly different way of operating this data. Yeah. Yeah. So the previous one was a profiling float. As the name says, it just profiles up and down and it drifts with the currents. This one is an underwater glider. As you can see here, it looks kind of similar to the previous one. It's also tube shaped, but it has wings. So the way it works is that it, it, it profiles the water column in a, in this sawtooth pattern. And I have a little, I have a little, little one here. I don't know if you can see. It just goes up and down in the water column like this in a sawtooth pattern. And it has wings. So it can kind of be maneuver a little more easily. But none of these instruments, they all, they don't have propellers. They don't have motors. They all rely on just changing. So they have bladders. I think the next slide maybe has an example of how what's actually inside of these instruments. So on the bottom there, the little yellow part, there's a bladder inside there that inflates. And whenever it inflates, it makes the float go up to the surface. Whenever it deflates, it makes the float sink. So just by doing that over and over, you can profile the water column. So just explain a bit more what it is we're seeing in this slide. The left-hand image is presumably someone throwing it overboard and throwing it carefully, presumably. But, but we're seeing these cutaway diagrams of what the, Yeah, this one, yeah, this one is really cool because they, they, they made these diagrams to, to make you look like, like they're transparent so you can see what's inside. But they usually have this yellow shell around it. And on the left there, you can just see the size, right? Like it's about the size of a person or so. And you can, yeah, you can throw it from, from the side of the ship. Some people actually throw it from aircraft. So they're pretty adorable little things that you could, there are many ways to deploy them. But then those, those diagrams there on the right, they're just showing you what's inside the float. So there's some batteries. There's that bladder that I talked about is on the bottom that inflates, that deflates to help the float go up and down. On top there, more on the right, you can see there's the, there's the antenna that, that helps you connect to the satellite and gives you the GPS position. So the latitude, longitude and time of each profile that you're collecting. And there's, there's also some snapshots of some of the, the sensors that you can collect or, or, or, or that you can attach to these profiling floats. So there the CTD is a conductivity temperature and depth sensor. And that's what's going to give you the temperature, the salinity measurements that I was explaining before, which are really basic for oceanography. There's also an oxygen sensor, the O2 there. There's an NO3 sensor, which is a nitrate sensor. So the all types of different sensors can be just attached to this body. And these are battery powered. We've had discussions of wave energy on an earlier show, but these sensors rely on batteries. So there's a battery run out of power. Is there any way of recharging it? Or do you have to go and pick up the sensor? Hopefully you can reuse it. Yeah, that's one of the, the tricky parts. So yeah, there's, they're all battery powered. So either alkaline batteries or lithium batteries, for most, most floats that are up there, they last between three and five years in the ocean. And then after that, the battery dies. So depending on where in the ocean the float dies, you can't really recover it anymore. But gliders, for instance, because they have those wings and you can maneuver them, as soon as you see that they are going down in battery, you can just, you know, bring them back to coast and then you can collect them again. Do you have any idea how much these things cost? I mean, are they millions of dollars or thousands of dollars? What order of magnitude? How much does one of these drifters cost? Yeah, so there's a huge range. So for a very simple one that has, you know, a temperature sensor or a salinity sensor and maybe oxygen, you're looking at about 25,000 per float. But it can go up to, you know, 80,000, depending on how many instruments you're attaching to it. Now the glider, the one with the wings, they're a little more expensive because they have a little, you know, they're a little smarter in a way that you can maneuver them. So they, they have a little more juice inside. But those can be, you know, around $100,000. So they are not cheap, but compared to, you know, how much it would cost to go on a ship and collect that information, like a ship day sometimes can cost $40,000 per day. So, you know, from one instrument of those, you can actually get a lot of information and you don't have to go out to sea. So That's nice. Now, do we build them here in Hawaii or are these commercially available? They are commercially available. There are a few, a few companies that sell them, mainly in the U.S. and in France. They're the two main regions where you, where you can buy them. But universities develop them. So the University of Washington has a big program for that. So we, we, we partner with them a lot to, to look at floats and gliders, but they are commercially available. Yeah. And I would imagine just building one of the instruments might be something that we could accomplish at the University of Hawaii and, you know, put it on somebody else's drifter or the gliders. Is that them? Is that them? Yeah. So we can definitely attach our own own instruments to it. The only tricky, the main tricky part is that we need a big tank to test them. And then sometimes that, like, you know, universities don't have access to a big tank where you can dump them in the water there. But I think here, you know, the tank is what you mean. Like a big swimming pool where you can, you know, sink the, the, the floats and check if it's properly balanced. And so that sometimes takes a little more infrastructure than the most universities. We've got the pool down in the quality. I mean, that's an opportunity, I thought. That's true. That's true. But I think, I even think here, they have a, they have a program or a few years ago where they were trying to develop really cheap autonomous vehicles. So there are lots of, you know, even as like grad school projects that you can deploy a little, a little like both surfboard with instruments on it and have it go somewhere. So there are ways to make it cheaper too. And, you know, especially if it's for coastal applications, which is a little closer to home here, if you don't have to, you know, to have the thing go super far away, there are definitely cheaper ways that you can do it. Right. I think your fifth slide really surprised me if we can take a look at that one. You know, I was quite impressed by the number of measurements that these autonomous vehicles, these underwater drones can actually collect. It explains to the viewers, you've got two global maps here. The gray areas are land masses, right, for the viewers. Okay. Yeah. So on the left here, you're looking at, you know, if floats did not exist, if none of these autonomous vehicles existed, that's every little dot there. They look like lines where they are little dots. They are each location where a ship one day has been to collect some sort of data.  So you can see there that, that, you know, over the whole history of us collecting data in oceanography. Most places in the ocean, they only have one to 10 data points. And they, you know, they are changing over time. So if we only have one to 10 data points in time, that's not enough to understand what's really happening in the ocean. But then with these, these deployments of these profiling floats and gliders and other autonomous vehicles, we have been able to extremely expand the amount of information that we get from the ocean. And that's on the, on the right there.  So it's huge amounts compared to what we can do with ships alone. So would it be correct to say you're looking at these two diagrams? There were a few data in 2018, but the vast number of colored dots in the January 2019 image is actually showing that this huge development of underwater measurements from, from drones. Would that be representative of where we are today? Or is there in fact a similar increase in number of data points being collected year after year? Yeah. So there's a program. So the Argo program, they aim to have about 4,000 floats at any time in the ocean. So that would mean, you know, one float every 200 kilometers in the ocean, more or less. And they have reached that goal.  So that's about 150,000 profiles per year that we get. But there are other types of floats as well. So the numbers are increasing over time. Yes. Okay. And so you're saying a few thousand of these floats at any one time in the Argo program, but each float might cost, let's say, average $50,000. So this is quite an expensive endeavor, right? So someone in Hawaii, you know, why would they be very interested in this sort of global data set? Wouldn't it be better just to concentrate the measurements closer to the Hawaiian islands, for example? Well, we are in the ocean and we are in the planet, right? That whatever happens here happens everywhere else. So if we all know about climate change, for instance, climate change is one of those things that we have been able to observe from profiling floats. They are measuring temperature and are measuring salinity everywhere. And from them, we can actually see how the water is warming up over time. And because of these profiling floats, not only have we been able to see that the surface of the ocean is warming up, which we have been able to see before from even from here from Hawaii, but also the bottom of the ocean is warming up. So that means that the entire, you know, ocean system is warming up, which is pretty serious. And, you know, what happens when water warms up, it expands and that means sea level rise. So, which is one of the reasons why sea level rise happens because of the expansion of the water, because of it being warmer. So we should all really care about where that's happening, because we are all affected by it. Last week, for example, Noah presented his analysis of sea level rise around Waikiki. And he touched on the fact that the sea level is rising partly because the ocean is getting warmer. You are able to provide that kind of information that even at great depths and presumably, you know, many hundreds, if not thousands of feet below the surface, the water is changing its temperature, as well as the chemistry. Has that been detected? Exactly. Yeah, that's perfect. Fine. And yeah, for instance, the pH of the water, right, how acidic the water is, we've also been able to measure from these floats that the water is getting more acidic because of the extra CO2 or carbon dioxide that's been added to the ocean because of burning of fossil fuels.  And you do need to have all of these data everywhere to be able to really see what's happening in a global scale. Okay. And viewers will hopefully see a future program where we're actually looking at the impact of changing acidity on coral reefs, which of course are really, really close to home. So your studies are providing background information, not only on sea level rise, but indirectly on the health of coral reefs or the ability of coral to grow around the Hawaiians. Absolutely. You've got some other slides. Do we want to look at number six, which I think is an Argo diagram. I modified this, I put red dots on, this is early 2022 data set. What kind of map is it that we're looking at here? Yeah, so here, here we're looking at a map of all the, it's called the biogeochemical Argo, which before I talked mostly about the Argo program, which has mostly temperature, salinity, oxygen, which are more primary variables that we measure in the ocean, primary properties. And these red dots here are the complementary to that data set. So they have more complex data. So here you're looking at about 500 points more or less.  So they are measuring the amount of sediment in the water or the amount of algae in the water or nutrients and pH. So there are less of those more complex floats in the water compared to just temperature and salinity. But still it's a lot. But you can see that some areas in the ocean are still, there's no information there. There are no floats in certain regions. Including between Hawaii and Alaska, there are very few of them there. And just for completeness, the colors, is that temperature or is that ocean color or what is the rainbow showing? Yeah, yeah. So the color in the background there in the ocean, so the whites are the continents and land masses. And the color is chlorophyll. So that's an indication of that there is the presence of algae in the ocean. So there are certain regions that you have, you know, more of those, some region you have less of those. Okay. And that's just a snapshot in time or that's sort of a monthly average? Yeah, that one is a monthly, no, let's see, it's a yearly average but just during spring. So we just pick all the springs and then you have the average. That's what it looks like. All right. And I think as we're a little short on time, let's jump ahead to slide eight. Okay. Which I believe shows a similar kind of data plot on a smaller area, right? Can you talk us through these gliders? I like it particularly because you've got changing days, right, to look at the temple variability. Yeah. So this is an example of how gliders can be used in very coastal environments. So here, these are little graphs of the white part there is the seafloor. So you're looking at the ocean from the side. So the white is the bottom of the ocean and the blue color is the actual ocean. And the color is going from blue to red is the amount of sediment in the water. So the redder it is, the more sediment in the water there is. And then what you're looking at is every day or so for a period of 12 days, I think it's a 12 day period, you can see how that section of the water changed. And this was during a storm, which is really, really cool because we can't usually put ships in the water when there's a storm, but we can put one of those unmanned vehicles. And this is just showing you how the water really changes as a storm passes by. Okay. So the vertical axis is depth below sea level. So sea level would be where each of the days. Okay. I would guess this is a really useful thing for people who are worrying about beach nutrition in terms of putting sand back on Waikiki beach or watering along the east coast of Oahu. You can really tell where the sand is moving around in that. Absolutely. And then also for biologists also want that because their organisms living on the bottom there who are affected by all these sediment moving around. So yeah, lots of applications. And there's day-to-day changes, right? Yeah. Between 1st of December and December 7th a week is completely different. Yeah. Yeah. Yes. We tend to think of the ocean as this big blue blob and there's a log going on underneath there and these things pop as check it out. And your last slide, slide nine, I think shows also just some of the experiments which you and your colleagues have been conducting north of the Hawaiian Islands. Yeah. One of these two diagrams. Yeah. So that's the Hawaiian Islands. The black lines are the tracks of the gliders. So these are the, I just picked the two last gliders that we've had here that were deployed near here. And there's a website there that you know people watching can go to the website and actually check out these data. So if you want to see what the water looks like around their region you just click on that website and you can see all these different properties. Right. I mean the diagrams themselves with the colors represent depths to the ocean floor. Okay.  It looks like this monitoring station, station of Oahu, the red dot. Is that where a lot of the experiments are being done? Yeah. So we visit that station every month or roughly every month. So that's when we get the opportunity to deploy these instruments and you know much safer to deploy them in a deep area because we know we're not going to hit anything. But yeah and then we can because they have wings and they can be maneuvered you can send them anywhere you want. So if you see a cool feature you can just okay go check that feature and see what's going on in there. So the gliders are super useful for that. When you get the data in real time you might get several data dumps every day so you can respond to a condition. And viewers are looking at this I really would encourage them to take a look at this website. I went on a yesterday and I had great fun because there's lots of photographs of the pilots and I'm guessing that Fernanda you can't drive one of these things it needs special expertise. But yeah you need a computer and connect to the internet and then you can pilot them from far away. Oh really? So that's all that is needed isn't some kind of protocol but you know you have to be in charge of the research project there. Oh definitely yeah it's not simple so we have people here at SOS who do that and but it's simple in a sense that you don't have to be present there for it to happen or you can do it remotely. So that's very powerful. One final question. None of these drones have cameras on board. Has anybody thought about putting underwater cameras to take a look at say the ocean floor or look at organisms in the water column? Yeah that's a great question. There are definitely floats or gliders that have cameras attached to them. They are even these very special imaging instruments that can you know take pictures of microscopic instruments or microscopic organisms. So yeah those definitely says they're very expensive but it can be done. And I would imagine that the data rate would be quite high for an image particularly if it's a color image you need a lot more bandwidth to the satellite communications. Yeah the cool thing is that the glider you can recover so at least you can have it saved. Yeah I hope you can recover. Well Fernanda I'm afraid we've run out of time so I want to thank you again for being on the show. Let me remind the viewers you have been watching Science at Soast. I've been your host Pete McGinnis-Marc and my guest today has been Fernanda Hendricks who is an oceanographer and we've been hearing about underwater drones. So thank you very much for watching today and until next week goodbye from me and goodbye from Fernanda. Goodbye. Thank you so much for watching Think Tech Hawaii. If you like what we do please like us and click the subscribe button on YouTube and the follow button on Vimeo. You can also follow us on Facebook Instagram Twitter and LinkedIn and donate to us at thinktech hawaii.com Mahalo