Hi, my name is Monty Johnson. I teach philosophy at the University of California, San Diego, and this is the fourth of six lectures on Lucretius, this one about sensation, illusion, thought, and desire in De Rerum Natura Book Four, and I'm using the translation of Cyril Bailey, which is available in the public domain through the Internet Archive. Now Think of where we are in the overall structure of this epic didactic poem. We've already proven the existence of an infinite number of atoms moving in an infinite void space and them getting entangled and colliding to form complexes and compounds, which themselves combine to form complex objects that are big enough for us to see and perceive. And some of these objects are living and have souls. All this has been explained and shown. Now we move on in book four to discuss higher psychological faculties like sensation, desire, and thought. So we've moved from the microscopic level of atoms and void to the level of psychology discussing the human soul senses in the mind. And we're using the physical assumptions and propositions, basic propositions of atomism to draw out some macroscopic implications for phenomena that we see and perceive, and also ethical implications for them because of how these things affect our desires. And so we move into the adulthood of the figure past the midway point between the birth with which the overall poem opens and the death with which it ends, and we move on to the complicated subject of human sensation and desire. Now book four, it's basic outline. The first 50 or so lines are the introduction. Here we have a reiteration of the poet's mission and the therapeutic purpose of the work and a summary of the preceding book in an overview of the contents of the present one. The 1000 lines of argument present a materialist and atomist account of sensation that it occurs through contact of sensible objects with sense organs gives an account of all five senses plus thought of sex, nutrition, motility, sleep, dreams, and sexual desire showing how they can all be explained on a materialist basis.  Now, the introduction or poem to this book is especially problematic because there's repetitious material here. First, the exhortation to philosophy is here from book one, which describes the therapeutic purpose of the work and offers a comparison between medicine and philosophy is repeated here, including the lines about coding the cup of bitter medicine of philosophy with the sweet honey of poetry. There are also two different versions included here of the summary of the previous chapters, one of them summarizing the material from book two, the other summarizing the material from book three. This is led and this is some of the strongest this is led some interpreters and this is the strongest evidence for the idea that the poem was left unfinished. I suspect all this repetitive material and especially two different versions of the introduction, which presumably the second description of the previous book is the true one if book, the present book is correctly positioned as book four should be describing the context contents of book course, the contents of book two preceded book three so it's useful to have that reminder of the contents of that book anyway. Now the arguments in book four to give an overview of them the basis of all sense perception is material objects called simulacra, which are translator Bailey translates as idols other translators use the idea of images. These material objects make contact with our sense organs, and he's most interested and most keen to describe phenomena of sight and vision, including optical illusions, and describe how the simulacra are the basis for those kinds of sensations, but he also explains hearing taste smell and even thought on the same basis. And in fact he takes touch to be the most fundamental kind of sensation and every modality of sense to be a form of touch because the ultimate explanation for all sensation, of course, is about contact and collision of atoms in void. So after explaining sensation he moves on to explain other vital functions on a materialist basis as well, including nutrition, voluntary motion, sleep and dreams and sexual desire. And there's an amazing kind of build up and then finally climax almost literally in the part on sexual desire, where we move through all of the five senses into a description of how nutrition affects us and the kinds of desires we have for food and drink that are manifest in hunger and thirst and how that compels us to voluntary motion of our limbs and then a description of how the voluntary motion of our limbs slows down and stops and sleep where we still have dreams and so still have some kind of sensation or recollection of these simulacra and idols.  Now the overall and detailed argument depends on accepting the view that small material bodies simulacra or idols are emitted from basically all parts of sensible objects but especially the outermost surfaces of them. And to convince us of this Lucretius points out that many objects emit scattered particles from themselves like wood, burning wood emit smoke, fire gives off heat, snakes and grasshoppers shed to coats. Now since these larger bodies are sloughed off of smaller objects then it's plausible to think that smaller and thinner bodies like these simulacra are might constantly be being sloughed off of larger objects like whole animals or human beings. And the idea is that the outermost layer of atoms making up the body has nothing impeding its departure so it's projected outward in all directions followed by the next layer of atoms which itself becomes the outermost and this process is happening continually. And colors are being conveyed to the eyes from the very surfaces of objects in this way as when colors are thrown off of awnings in a large theater and sort of projected out into space off of the material cloth themselves. Now when particles are emitted from deep inside of objects as smoke from wood then the color is darkened because of deviation in its trajectory but when they come from the outermost surface of objects and in straight lines then there's nothing to impede them and this is why vivid colors are conveyed. And Lucretius frequently appeals to the phenomena of mirrors in order to show that material objects must be thrown off of sensible objects that are reflected back to the sense organs from the mirror. Now these idols are extremely small but they can still be caught up in their transmission from the objects to our sense organs. So he says they're much smaller than the smallest visible part of any animal in fact they're one atom thick and so they how can they be have such an effect on our senses well it's comparable to the power of the effects of things like perfumes or incense when we can't see the particles affecting us but nonetheless we can smell them or detect them in some other way. We can't see the particles that we taste but they still affect our organs and they are transmitted sort of instantaneously to us and they can affect and alter our perception very rapidly. He says like images in clouds do which seem to instantly form and reform into different shapes a ship a house a face and so on and affect us instantly. Now there are three different possibilities in the transmission of these idols or simulacra from the objects to our sense organs. They can travel through certain bodies that have a lot of void and a lot of pores like the air or like glass and thus those media are we say transparent or they can be blocked and smashed up by solid and rough objects like stone or wood. And this is why we say those are opaque we can't see objects that are behind stone or wood walls because the idols that are being transmitted from the sensible objects in the next room get smashed up and blocked by these opaque objects. But another option besides transparency and opacity is when the idols come streaming back from the surface of an extremely smooth surface like a mirror or a pond. Such surfaces contain insufficient pores to be traveled through like transparent objects but they're too smooth to smash the simulacra or idols and so the image itself is cast back in the same direction. Now the idols are being transmitted extremely rapidly essentially the speed of light or even faster they move he says at the same roughly the same speed as the sun's light and heat are transmitted. And again compare how quickly images and clouds can be formed and reformed or how quickly something that's even very far away in outer space like a star can be immediately reflected in a pool of water or a mirror. If you if you put it in view and so that means they must be transmitted at the speed of light or very fast and how can they move so quickly well because they're so small and so light. So they don't collide with any other ambient bodies in the atmosphere because they are so small and they weigh so little there is nothing to stop them from moving as fast as possible essentially like atoms in void. Another reason they move so quickly is that they're emitted from the outermost surfaces of things not from their inner parts which would take longer and slow them down in the transmission instead they move directly from those surfaces to the surfaces of the sense organs. Now all sensation is thus treated as a kind of touch because in the Epicurean theory of perception all sensation is described as a kind of impression or contact between the atoms that are emitted from the surfaces of the objects and the atoms that comprise the sense organs. So there always has to be some kind of contact at basis for any form of sensation to happen and this applies as we've just seen to seeing because seeing occurs when idols or simulacra are transmitted from the outermost surfaces of objects to the surface of the eyeball. But the same process applies to smelling tasting hearing and so forth in these cases atoms are emitted or flowing from the surfaces or the internal parts of objects and they make contact with the atoms come constituting our noses tongues ears and so forth and the result of those combinations and juxtapositions are the alterations of senses that we perceive. So to go into a bit more detail into each one as he does beginning with seeing again the theory is that images are being emitted from the surfaces of the object but here Lucretius adds the detail that they move the air between the objects and our eyes so the eyes then receive an impression from the imprinted air. And Lucretius tries to explain why distant objects appear less distinct to us by appealing to the fact that the intermediary air is more disrupted there's more room for disruption so the intermediary air blocks and distorts the imprint so they don't appear the visible object doesn't appear as distinctly. Now of course we cannot perceive a single idol or simulacrum just as we can't perceive a single atom of wind or a single atom of cold or of a solid object like a stone we can't perceive single atoms at all. We need enough of them collected and enough of them inundating us to activate the alteration of the atoms in our sense organs in order to have the experience. And Lucretius offers an extensive discussion of mirror images including accounting for why mirror images are reversed and what happens to images when they're reflected through multiple mirrors and so forth and all of this according to the theory of idols or simulacra. And he goes into enormous detail on optical illusions and the reason he spends so much time on this is more or less clear because they are a big challenge to the Epicurean theory of perception. Again the Epicureans identify perception with sensation and reduce all sensation to touch claiming that ultimately collisions of atoms transmitted from sensible objects with atoms constituting these sense organs are what constitute the alteration of sensation and less perception. But they build an entire theory of knowledge on top of that entirely objective process. So in theory every sensation is true insofar as it's just a reception of the object it was admitted from into the objects that constitute my sense organs. So when things end up other than their objects actually are there is a problem and this needs to be explained and so Lucretius goes into detailed explanations about phenomenon like glare and excessively bright objects, yellowed or pale colors, lightened or darkened objects, square buildings appearing around at a distance, shadows, motion after effects, horizon and vanishing effects, why ores appear bent in water, why you get double vision when you apply pressure to the lower part of the eye and of course dream images. All of these effects he says have naturalistic explanations according to the theory of idols already outlined. And although they seem to threaten the credibility of the senses in fact they do not and reason can resolve this deception of the senses. In fact it's the mind that's been the cause of the deception and how it's interpreted the senses and if you look at it correctly the senses have always reported exactly what the objects are there's nothing else they could do. And again this is critically important for Epicureans because of their epistemology which holds that sensation is the criterion of all truth. They hold that knowledge is possible contrary to skeptical views they say that it is possible to have knowledge. If anyone argues that nothing can be known then he refutes himself since he declares that he himself knows nothing.  How does he distinguish knowing from not knowing that is how does he distinguish true from false and certain from doubtful. And Epicureans answers that there's no other means for distinguishing these things true or false other than the senses. Quoting Lucretius you will find that the concept of the true is born first from the senses and that the senses cannot be refuted. So reasoning can't refute the senses because reasoning is entirely based on the senses and one mode of sensation cannot refute another mode of sensation. So hearing can't refute seeing and seeing can't refute tasting and reasoning can't refute any of those individual senses. So each of the senses must be true or as Lucretius puts it therefore whatever they have perceived on each occasion is true. So it's better in each case to determine how reasoning or the mind is at fault than to find fault with the senses. Since the senses are the foundation of all reason and if they are threatened then reason itself is threatened. And reasoning based on false sense data is like a house built with flawed measurements. It's structurally unsound and liable to collapse that is it's not secure knowledge. So every sense is veritical that is every sense is true and perceives its own object and so each of them must be given their own accounts. So he moves on to accounts of the other sense modalities which I will pass through relatively quickly. Beginning with hearing sounds voices and echoes are all effects of bodies for which a materialist explanation can be given. They in turn affect our sense organs and then other parts of our bodies. Lucretius goes into a lot of detail about the effects of spoken voices on audiences. There's an outsize attention paid to that particular aspect of hearing. Apparently he's thought very deeply about the rhetorical and poetical aspects of speech and sound. And he does give an interesting account of why sounds can pass through objects that are impenetrable by visible objects and that's because they can somehow move through sinuous and tortured passages that are between the object and the sense organ without getting smashed up while the thin and tenuous visible idols must travel in straight lines and tend to become smashed up whenever there are passages that turn in their way. Now tasting is explained in terms of food particles being squeezed out in the mouth and distributed across the tongue and palate. All of it is just material bodies interacting with other bodies when the particles are smooth. There's a sweet sensation because they pleasantly stroke all around the moist sweating vault above the tongue but when they're rough they prick and tear it in onslaught and this is what produces a bitter taste. So we can explain all the various kinds of taste by describing the effects of bodies of a certain shape on the bodies that constitute the sense organs. Now Lucretius here digresses to explain why different foods are good for different creatures because different creatures have different constitutions and the food is constituted differently and not every combination is possible. Not every combination is healthy or harmful for different animals. Different things are healthy or harmful and thus they taste differently and for the same reason taste differs in the same person when they're sick because their sense organs are constituted slightly differently than the same kind of object interacts with a differently constituted sense organ thus giving rise to a different kind of sensation. Smelling too is of course based on a theory of particles which stream from different objects into the sense organ of our nose. Smells are not transmitted as far as sounds or images because they are emitted from the depths of things and they have more difficulty because they have to travel through more tortured paths to reach their sense organs. They also consist of larger particles and sounds and so they more easily get caught up in solid bodies like walls and can't be transmitted through them. Smells affect creatures differently because the particles differ in shape and indicate potentially good or bad effects on their health thus bees are attracted to honey, vultures are attracted to carrion and so on and in general different animals react differently to different objects because the particles they emit interact differently with their own differently configured sense organs so lions fear cocks because there is something about how they appear that actually hurts and tears at the eyes of the lion and possibly the other kinds of particles being emitted from it also interact in a bad way that's painful and so this explains their avoidance behavior. Now the account of thought is really an account of how imagination is possible and it's explained according to this theory of idols or simulacra which gets extended to the effect on the mind or animus which was the subject of discussion in book 3. Thought ends up being a kind of image making or imagination. It's really about calling to mind or focusing on certain idols or simulacra or certain combinations of them. We're just rearranging them and giving them various kinds of focus and attention. The idea is that there are innumerable idols that are constantly moving in all directions through the void and they can become entangled as they're transmitted to our sense organs and because they're ultra fine they pass beyond the sense organs even the organs of vision and reach deeper into the body and the spirits as far as the animus which is deep within the chest. Now this is used as a basis to explain why people imagine things like mythological animals, centaurs. They have idols of humans and idols of horses and somehow these have become mixed up in colliding either in the medium of air or within the sense organs of the subject so that a half man half horse is conceived. Of course no actual centaur ever existed and that's why there's never any direct perception of them. But all imaginary creatures have some basis in recombination of actual sensations. Now a couple of questions about imagination and thought that Lucretius addresses. First, how can the images be imagined to move? After all, all we receive is, as it were, a set of static images that are constantly flowing off of the surfaces of the objects. The appearance of motion in both dreams and imagination that these aren't just static images but they're moving he describes as a kind of animation due to rapid succession of the images since each image is at a slightly different posture or position than the illusion of moving is produced. And he also offers to explain how the mind can think whatever at once it will and spontaneously produce an image of it, you know, think of an elephant, you can immediately do that and you can even imagine an elephant moving and walking across the plane. How is this possible? He says that in any period of time, including a temporal minimum of just a moment, there are in the mind, what we would call I guess the subconscious mind, innumerable images lurking and lying ready to be focused on by the mind. We have this vast reservoir that are constantly flowing into a pool of them. They're so small and ultra fine they can all be collected in this area of the mind in the chest. But because they're so small, the mind can't apprehend them clearly unless it concentrates or focuses attention on them repeatedly. And that's why if we have, you know, more experience, we can find them and focus on them more easily. But in sleep, they also pass for our mind. But since we can't use the other senses or our memory to judge and check them, they appear as if they're really happening. And that's why we can't tell that we're dreaming. And then when we're awake, our conscious attention is so flooded with the things that we actually are sensing and actively perceiving and calling to mind with our imagination and memory. It blurrs out any of those subconscious images. Now, a small digression on the natural history of the senses. Lucretius argues that the natural organs existed prior to their current uses by contrast to artificial tools which are designed and created after a purpose has already been conceived of them. So nothing is born in us for the sake of its use. Rather, that which is born creates the use of its senses and its limbs. So the eyes came to be before sight and the tongue before speech and the hand before grasping. And somehow the tongue was put to use by a creature in producing speech. It's not that some intelligent designer had conceived of speech and this would be a good idea and so designed to the tongue so that it could speak. Now, by way of contrast, murdering and fighting existed long before swords and arrows, dodging existed before shields and sleep existed before beds. These artifacts were produced for the sake of those natural uses, but they are in a different category from the natural senses and limbs which were not designed and weren't recombinations of matter deliberately put together for the sake of those uses. Now, the next vital function that Lucretius discusses is nutrition. Drinking and eating basically replenish this material that's constantly being sloughed off and lost from the body by this constant emission of idols, sounds, odors and so forth that we're throwing off and losing from the surface of our body. We need to sort of replenish that from the inside and eating fills up interstitial voids whose continuous growth in the body causes this sensation, this desire of hunger. And similarly, drinking provides fluid to help cool and extinguish the body because there's this heat in our stomach that sort of cooks our food and it will produce a scorching effect and gradually dry us out causing thirst unless we provide fluid to cool and extinguish it. And that's why we have a desire for thirst. So these primary desires for hunger, thirst and things like this can be explained in terms of the material lacks and voids within us. Now, the next thing to be described is how we can voluntarily move ourselves in order to cope with this hunger and thirst. That is, how can we, how can we feeling thirst move towards water in order to drink it or feeling hunger move towards food in order to eat it. And in general, if you think about it, and it's still a pretty good question, how is it that we can move our limbs at will? If we think about something that we desire, we're capable of moving towards that object, but how can something as small and insignificant as a thought move our large and weighty bodies? Well, Lucretius provides a fascinating mechanistic explanation. Now, by mechanistic explanation, I mean that his explanation is modeled on the way that the science of mechanics explains the working of machines. Lucretius himself doesn't provide an explanation of how any machines work, like pulleys, rudders, sails, etc. But he provides explanations of other phenomena, biomechanical phenomena, modeled on those mechanical phenomena. So the basic mechanism is like this. So an image makes an impression on my mind, for example, an image of chocolate cake. Next, I formulate a will to eat that chocolate cake. So I foresee my doing it. I combine an image of me moving towards the cake and eating the cake. And this foresight, this thought, which is again within the soul, the smallest of the atoms that makes up the soul body compound. This soul atom strikes the animal spirits, the larger animal spirits within the body, which it's easy to do because the mind or animus is closely connected to the spirit. And the spirit atoms then strike the even larger air, soul air atoms, and then the air pushes out to impact with the rest of the body, the outer limbs of the body, so that the whole mass is pushed and moved, as he says, as a ship is by sails and wind. So the tiny image moves the slightly larger soul atoms, which move the slightly larger spirit atoms, which move the slightly larger air atoms, which hit against the, as it were, sails at the ends of our limbs, which then move the limbs. Then the limbs are able to move towards the chocolate cake or the object as intended and eat it, thus satisfying this desire for cause by hunger or expanding voids within the body. And Lucretius compares all this to the way rudders and pulleys can cause very small forces to be amplified and have large effects, just as invisible wind particles are able to move a large ship. So these ultra fine image particles are able to, by causing this kind of chain reaction of the soul, spirit, and air particles within us move a large and weighty body. And so he gives an entirely materialistic mechanistic explanation of voluntary motion. Interestingly, no mention of the swerve here in earlier discussion of voluntary motion in book two described the swerve and then gave a similar mechanistic but shorter mechanistic account of how motion works. So we can infer that a new swerve is apparently not necessary to explain every voluntary motion because we've just had an explanation of voluntary motion that occurs as a result of a chain reaction from an image to a movement of the overall body. Now, after the discussion of how the body moves, we need a discussion of how the body stops moving and an explanation of why it goes into sleep, which we spend such a great portion of our lives doing. Sleep, he says, involves the departure of some of these spirit atoms so crucial to moving the body in voluntary motion. Some of these spirit atoms depart and dissipate from the body and others retreat to the innermost parts of the body so that the outermost limbs remain inactive. Of course, only part of the spirit leaves. If all of it left, the result would be paralysis and death. But the overall cause of sleep is due to the fact that our bodies are constantly being buffeted by air from the outside. Our skin is partly protective against this, but not only that, when we breathe in the same air beats on the inner parts and being beaten both internally and externally, the structures and passageways of the limbs collapse. And so the balance of body and mind atoms becomes disordered when the part of the spirit retreats and draws inward. It's no longer in communication with the outer parts of the limbs and so it can't move them and the limbs being unsupported then relax. And he says, food has a similar effect on internal buffeting of organs and that's why eating a lot can cause sleepiness. Now after explaining sleep, it's natural next to explain dreams. Dreams again are given a materialist explanation. He points out they mostly relate to things we sense in waking life and things we do in waking life thus lawyers dream of pleading in court and generals dream of engaging in battle. Sometimes we can even be so conditioned to seeing or hearing things that we see images or hear sounds of them even when awake. As in daydreaming or deep intense kinds of imagination or visualization, dreams are very similar to this. Animals also dream, horses he says, dream of their races, dogs of the chase, birds of being pursued, just as kings dream of victory. People even talk in their sleep about their secrets from waking life. Now dreams that we have about falling or being thirsty or wetting the bed involve vivid images of things encountered when awake. So all of these kinds of dreams are explained as being the persistence of images taken into the sense organs when we are awake and running before our minds when our minds are not being clouded out by other kinds of sensation, memory, imagination and thought. The final kind of dream he gives an explanation of is wet dreams, which he says occur once seed that stirred up at the age of full growth. When images from chance bodies fly from abroad come to the mind in dreams, then they cause a release of this seed. And this is the transition between the topic of dreams and the final climactic topic of the book for the discussion of sexual desire and procreation. Again, we have a purely materialist and atomistic description of it. It's amazing to think that this explanation has been built in a continuous succession going from sensation up through thought, nutrition, sleep, dreams, imagination and now sexual desire. And so he says that sexual desire is caused by seed being stirred up from within the body and withdrawn from all the limbs and all the different members, gathers in the region of the loins and arouses the body's genital parts, which become excited and swell. And this produces a desire to emit the seed that is accumulated and quote, the body seeks that which has wounded the mind with love. So he imagines that there is that the sense organs have been affected by an image of a boy or a girl who's described as inflicting a wound of love upon them. And the effect of this wound of love is that there's a burning desire to eject the seed in that direction just as blood from a wound jets in the direction of the blow that inflicted it. So desire to emit the seed is directed at the source of the wound of love. This Lucretius says is our Venus. And of course, he puts it very beautifully and poetically and I have not done any justice to that poetry and in fact I'm discussing the most prosaic aspect of it how it relates to this underlying materialist atomistic thesis. And here when he says this is our Venus, it calls to mind the opening of the entire poem, the invocation to Venus, Venus being the Roman version of the Greek goddess Aphrodite, the goddess of erotic passionate love and sexual intercourse creation and reproduction has been reduced in this materialist account to certain bodies affecting certain other bodies and swelling and being admitted and then colliding in various ways. And so the goddess there has been, as it were, obviated by an naturalistic materialistic atomistic Epicurean description of the cause and effect of sexual desire. This leads then into moralizing about sexual desire and procreation and Lucretius warns against passionate love and advises that one should avoid and even scare away whatever feeds passionate love. One should in fact he says find persons with whom one is not in love in order to have sex with so that the wounds of love will not be worsened. That leads to a kind of madness. So he gives exactly the contrary advice that our parents do.   Lucretius asserts that people who are not afflicted with love can actually have more gratifying sexual pleasure and he describes passionate love as being frenzied and mixed up with pain. And furthermore, passionate love causes desires that can't ever be satisfied and the madness produces all imaginable vices, luxury pangs of conscious jealousy and so on. Unsuccessful love is of course even worse and should be avoided at all costs. Passionate love makes one overlook grave faults of the beloved and has all kinds of distortive effects. He does point out that women can be just as passionate and derive as much pleasure as men can from sex and he seems to encourage that. Now the book ends with an account of heredity, the final effects of passionate love on procreation. And he presents briefly the idea that the male and female seed is mingled and transmitted from generation to generation. And he uses the same kind of theory to explain barrenness, there must be incompatible shapes that somehow fail to mix in necessary ways. And he actually recommends certain sexual positions that he suggests may increase or decrease the chance of conception. And he concludes by discussing how one may come to love a plain woman and thus avoid the snares of passionate love. So ends with an ethical Epicurean extrapolation about limitation of our desires built up on top of an entirely naturalistic thesis stemming from the smallest imaginable kind of atoms constantly being transmitted in every direction in the void to their ultimate effects on our desire and behavior and reproduction.


In looking at free or natural convection it is quite instructive to take a look at what is happening in terms of the fluid mechanics and so that is what we're going to do in this segment. And so before jumping into looking at the governing equations and things with the velocity profile and non-dimensional numbers, what we're going to do we're going to begin by looking at a fairly classic example of free or natural convection and that is one that deals with a heated or cooled flat plate flow. So what we'll be looking at in this segment is a vertical flat plate and we'll begin by looking at a flat plate that is cooled followed by one that is heated. So let's begin by looking at the cool flat plate and in order to do that what we'll be doing is we'll be looking at a video and what we have here is we're pouring boiling water and vinegar, water on the left, vinegar on the right, into a container that has ice water in the middle. So you can kind of see there's something in the middle that's a stainless steel tube that has ice water in it so we have hot fluid on the outside and you can see the index for fraction variations in the liquid, it's quite prominent. And then what starts happening you can see along the ice water surface or the cooled surface the fluid is descending and you can see it in waves and I've taken this, we're looking at about four and a half minutes of time here, convinced into shorter periods of time but you can see the cool fluid descending along the ice water, the stainless steel cylinder in the middle and as it warms up and the fluid on the outside cools then we come into equilibrium and the driving force goes away and that's why it becomes less and less pronounced with time. And so eventually you can see there are just small waves going through. So that's an example where we have vertical flat plate and we have a cooled surface and consequently the fluid on the surface becomes more dense and it then moves downwards. And so that is one application that we can have with the flat plate. Now the one that we're probably more used to is where we have the flat plate being heated and so that's what we're going to look at in this clip. And so here we can see a barbecue. There is the hot air coming up on the outside of the barbecue. It's going around a corner and so starting to separate and then eventually it merges with the byproducts of combustion coming out of the barbecue at the top and so you could see the thermal boundary layer in that case as well for that clip. So what we're going to do, we're going to take a look and we're going to look at the second video clip that we just saw and that is the case of a heated vertical flat plate. So let's examine that. So what I'm going to do, I'm going to sketch a vertical wall. So what we have here, we have a vertical heated wall. X is going in the vertical direction. Y is normal to the wall and the wall temperature we're assuming that is it is hotter or warmer than the ambient fluid which is out here. But what happens as we move upward along that plate, we do get a boundary layer forming and you could see that in the barbecue video, the one where we have a heated vertical plate. And you're looking at the index refraction variations within the air that is next to the hot vertical surface and it becomes at a higher temperature and consequently less dense and then that is what provides the mechanism that moves it upwards. But what will happen just like we saw for the flat plate with force convection, we go through a transition process where we go from laminar and then we move into a turbulent boundary layer that is on the surface. And so let me just sketch that out. And if we were to look at the temperature profile at any given location, now here what I've sketched, this is the boundary layer. And for now let's assume that the velocity boundary layer and the thermal boundary layer approximately the same thickness. That would depend upon the parental number just like we saw for force convection. But if you were to go and place a thermal couple along the wall and then do a traverse, so moving the thermal couple out in the Y direction, that would enable us to measure the temperature profile. And if we were to do that, the temperature profile in our boundary layer would look something like this. Remember the wall is hotter than the ambient fluid. And so eventually what we would find is that when you get outside of the boundary layer, you're going to get to a temperature that is T infinity. And as you move in towards the wall, what's going to happen is the temperature is going to increase. That's not a good curve. Let me redo that. So you're going to get something that might look like this. So the temperature as we move in towards the wall is going to get hotter and hotter. And eventually we get to a point when you reach the wall, the boundary condition on the wall is that the fluid temperature right at the wall surface has to equal the wall temperature. So we would have that at that location, T wall. And then we would have this profile, T of X, Y. And consequently the temperature profile is going to vary not only normal to the wall, but also as we move upwards along the wall. So it's a function of both X and Y. And if we were to look at the velocity profile, the velocity profile would be quite a bit different from what we saw for the boundary layer for force convection. And so I'm going to try to sketch that out. And what happens when you leave the boundary layer, you get into what we would call a quiescent fluid. And there the velocity is zero. And that's something new. We didn't see that before when we were looking at force convection. So the velocity has to go to zero outside of the wall. And then if you were to again place a probe that enabled you to measure velocity normal to the wall, you would find a profile that would look something like this. It would spike up and then it would come back down towards zero. And this then would be the velocity profile normal to the wall. And again it is a function of X and Y. And so that is the thermal boundary layer that we have. And this is going to be very important in terms of determining what the convective heat transfer coefficient is. And just like for the flat plate flows or any of the flows that we looked at for force convection, we'll be able to do a little bit of analysis for laminar. And we have a laminar flow. But when we go to turbulent, what we're going to be forced to do is rely on empirical or experimental data. So that is what the boundary layer flow looks like when we have free or natural convection.


When it comes to economics and the managerial decision making, we need to see that how there is a relationship with the other business, discipline typically this managerial economics. We talk about demand and price elasticity in case of managerial economics, which has also a link with the discipline of marketing. We talk about the capital budgeting, break-even analysis, opportunity cost, economic value divided that has a relevance with the finance. Then we talk about linear programming, regression analysis, forecasting that is part of the management science. So, even if this topic we cover in the managerial economics, it has also a link with the other business discipline like marketing, finance and the management science. Similarly, this has a relationship with the strategy that is type of competition, structure, conduct and performance analysis, it has a relationship with the managerial accounting that is relevant cost, break-even analysis, incremental cost analysis and opportunity cost. Now, what are the question, what is the general question the manager must answer or from here we can form what is the what kind of we can form an opinion that what kind of managerial decision problem is generally involved in the organization. Now, the question that manager must answer what are the economic condition in a particular market, what is the market structure, what kind of form of market it is being followed, what is the supply and demand condition, what is the technology being used, what kind of government regulation is there, what is the international dimension, interim of international trade and international finance, what is going to be the future condition for this firm and what are the macro economic factor that is change in the macro economic variable, change in the government policy or change in the economic environment of economy generally how it affects the firm. Then the question that manager must answer looking at all this factor whether it is technology, whether it is policy, whether it is relationship with the international or the world economy, the question that manager must answer is should our firm be in the business, if so what price and output level achieve our goals. So, if you look at these are the two basic managerial problem what the manager face that is should our firm to be in the business and if so what is the price and output level is required to achieve our goals. Here we need to specify whether the firm is having a profit maximization goal, whether the firm is having the revenue maximization goal. Then looking at this there are few more set of challenges that is for the managers, what the managers must answer that is how can we maintain competitive advantage over our competitor that is we will take typically through the product differentiation, whether it is a cost leader, whether it is a low cost firm, whether it is a high cost firm. Product differentiation should be in term of content, in term of quality, in term of the services, whether it is a niche market, whether the outsourcing alliance merger equation is going to the beneficial and again what is the international dimension that is in term of the merger, merger equation alliance and the outsourcing. So, here again the another challenge comes from the manager that what are the risks involved in that and what is risk, risk is the chance or possibility that actual future outcome will differ from those expected today. So, after taking all this decision whether it is related to price, whether related to output, the manager is also need to answer that what is the risk involved when the firm is taking a specific price strategy or specific output plan. So, that is again they had need to know the economic concept and economic principle to understand this. Now, what are the type of risk over here, there is a risk associated when there is a change in the demand and supply condition, there is a risk associated when there is a technological changes and the effect to competition, there is a risk associated when there is a change in the interest inflation rate, risk associated with the exchange rates for company engage in international trade and also risk associated with the political risk for the company with foreign operation. So, now we will take a small example to understand this how this generally from the day to day activities of the company, how this manageral decision problem involved. So, if you have some idea about this sub-drink manufacturer Coca Cola and Pepsi, there are two major sub-drink manufacturer in the world, they manufacture only concentrate and shift to the network of the bottler and who finally gives the bottled sub-drink. In 1919 Pepsi bottling group following Coca Cola bottling company and what they did, what they did, they denounced the increase in the price of concentrate and how they did that because in November 1999 Coca Cola also announced the increase in the price of concentrate by 7 percent. Before that also Pepsi followed the another decision of Coca Cola like Coca Cola separated its manufacturing with the bottling company and the same decision is followed by Pepsi. So, whether it is the separation of the bottling company or whether it is the increase in the price of Coca Cola, immediately both the decision get followed by the Pepsi group. Now, 7 percent increase in the price will lead to increase in the retail price from 1.99 dollar to 2.49 dollar. So, price increase is welcomed by the beverage digest editor with the justification of improving the overall profit and margin. So, when there is a 7 percent increase in the price of the product that leads to increase in the retail price from 1.99 to 2.49 dollar. However, the increase in the price is where welcomed by the beverage digest editor and the justification for approving this is that there is overall profitability and margin and that is why the price should increase. Now here how we can reframe this to a question of managerial economics or part of managerial economics or part of managerial business decision. If coke increase its price by 7 percent should Pepsi follow, this will typically address in the theory of market, typically address when you talk about the elasticity of demand. How would the price increase affect the consumer demand? It is again the price demand relationship and the elasticity of demand. How should advertisement expenditure to be related to pricing? Here we talk about the cost of production, how advertisement cost increase the average cost? This we will discuss in the case of cost analysis and the monopolistic competition. Was it correct for Pepsi to follow Coca-Cola in separating bottling business from manufacturing concentrate? This we will analyze through our oligopoly market structure generally how the firms behave in a market when there is a they knows that there is a interdependence between both the firm in the typical market. Then here again the question related since the profitability of both the company also depends on the sensitivity of the consumer demand to price increase and the cost of sweeteners and other inputs, they need to check what is the sensitivity and the sensitivity can be analyzed through the elasticity of demand. What price should Coke and Pepsi pay for these outputs? Here again we will see that what is who is going to decides the price. So partly it will be address in the cost analysis and partly it will be address in the market structure. How are they affected by the shift in this market? So here again we will discuss this in the context of the demand analysis and the theory of market structure. So it is just a small example to understand the difference between the understand the relationship between two companies that is Coke and Pepsi. It is an event if you look at it is an event it is an economic activity and similarly for the other economic activity that what happens in the day to day business life that can be that solution can be found by using the economic concept and economic principle and this generally we address in the managerial economics. So the entire managerial economics course is planned in four module. Module 1 talks about introduction to managerial economics. Typically the economics term what generally being used and the basic economic analysis and the optimization technique. Then theory of demand will address the relationship between demand supply market equilibrium and also the demand forecasting, then theory of consumer behavior, then theory of production and cost basically deals with the short run long run production analysis, short run long run cost analysis, expansion path and economic region of economic region of production and also the economic of scale. Finally module 4 will talk about the different kind of market structure, the pricing practices and finally the sum up of the entire course. So to start this module 1 where we basically deals with the economic terms or the basic assumption generally will be using for the entire course or the entire what is the basic assumption generally used for all economic principle we are going to discuss this. So there are two assumptions mainly taken one is satiriparibus another is the rationality. What is satiriparibus? It is a Latin phrase that means all variables other than one being studied are assumed to be constant and here the literally the satiriparibus means that other things being equal. So if there are five variables the study variable are five when the relationship between two variables are being studied the other three variables has to be constant. So satiriparibus means all variable other than one being studied are assumed to be constant and the literal meaning of satiriparibus is other things being equal. So that is the assumption that is the basic assumption we follow for all all of our theory all of our principle. Then the second assumption comes as the economic rationality and here rationality implies basically acting objectively keeping in view the entrant means the objective and the constant. So if laymen understanding rationality is one where we are not biased for anything rather we are unbiased and keeping the objective in mind we take a decision or we take a activity. So it is implies acting objectively keeping in view of the end and means and the objective and the constant. It generally in economics we assume the rationality on the part of its subject like all the economic agent that is consumer, producer, seller, firm or the economy as a whole. So economic rationality means economic agent see feasible known and alternative course of action and rank them on the priority and choose the one which is highest in the ranking order. So rationality is one where if you look at the process if you define the process first the economic agent has to see what is the feasible course of action that is known to them what is the alternative course of action then they will rank them on the basis of the priority basis and they will choose that option which is highest in the ranking order and that is generally known as the economic rationality. Then we will talk about the resources there are when mainly four factors of production or the four resources that is used in economics that is one is land or any production process these are the factor of production and these are land, labour, capital and entrepreneurship. So land refers to everything on earth that is in its natural state or on the earths natural resources. Labour refers to all the people who work in the economy whether they are skilled whether they are on skilled and accordingly the remuneration for both of them changes. So for the skilled labour we will always say salary for on skilled labour we always say wages and land refers to everything on the earth that is in a natural state or earths natural resources. However the definition of land changes when the reclamation is being also done so that is also to be added in the in the list of the possible list of the land. Then capital it includes money needed to start and operate a business at a national level capital includes infrastructure such as roads, ports, sanitation facility and utility services and also in the industry level or farm level even machine can be considered as capital because that they are also one kind of infrastructure to produce the goods and services. Then the last factor of production is entrepreneurship it is referred to the skill of people who are willing to rest their time and money to run the business. So manpower uses of skill and their time and money to run the business that typical that is known as the entrepreneurship. So we know that there is a scarcity and what is scarcity? Scarecity is the condition in which resources are not available to satisfy all the needs and want of the specified group of people. And if you look at most of the underdeveloped nations have natural resources but do not have capital or the skilled labour to develop them and that is why there is a scarcity. And since there is a scarcity the allocation decision must to be made and what is the allocation decision? It comprises of three separate choices that is what how many goods and services should be produced? How should these goods and services be produced and for whom should these goods and services to be produced? So what to produce, how to produce and for whom to produce three basic allocation problem or the three basic question that is generally known as the three basic economic problem that is one what to produce, second is how to produce and third one is for whom to produce. On this basis on these three basic question the economic decision for the firm is dependent typically when it comes to what it is about the product decision of the firm whether to begin the production whether to stop providing goods and services. Now the hiring staffing procurement and capital budgeting decision and for whom the market segmentation decision targeting the customer most likely to purchase. So what consider to the product decision of the firm, how is basically the hiring staffing procurement capital budgeting decision and for whom also the market segmented decision that is targeting the for the customer who are the end users to purchase these goods. Now from here there are three processes to answer this what, how and for whom. One is the market process here generally the use of supply demand forces material incentive to answer this what, how and for whom. In the command process there is a use of government or the central authority usually indirect process and traditional process when there is a use of custom and tradition to decide what, how and for whom. On the basis of three processes generally we can define the different types of economy and what is the economy and economy is the economic system or is the way the nation make economic choices about how the nation will use the resources to produce and distribute goods and services. So from here the first kind of economy come that is market and capitalist economy and in a pure market economy there is no government involvement in the economic decision the government lets the market to answer the following three basic question that is what to produce, how to produce and for whom to produce. So in a market economy there is no government involvement this is also known as the capitalist economy. Generally the free hand principle or the invisible hand principle works here the market forces correct imbalance itself whenever it is required. So the second in the market capitalist economics how the what is decided the consumer decide what should be produced in a market economy through the purchase the makes. So the consumer decide what to produce because ultimately they are the end user. How to produce the production is left entirely up to business, businesses must be competitive in such an economy and produce quality product at a lower price than their competitors and for whom typically in a market economy the people who have more money are able to buy more goods and services. And typically the market and capitalist economy based on the Adam Smith invisible hand principle and typical example of market and capitalist economy is USA and the European countries. Then the second kind of question second kind of economy is command and capitalist economy and in the command economy the government answers the three basic economic question that is what a dictator of the central planning committee decide what products are needed. How since the government owns all means of production in a command economy decides how goods and services will be produced and for whom the government decides who will get what is produced in the command economy. And typical example of command and socialist economy is China, Mexico and former USSR. What is the essential difference between the market or capitalist economy and command and socialist economy? In market and capitalist economy there is absence of government intervention, the market forces is free, the invisible hand principle works, the market forces decides or the consumer producers decides what to produce, how to produce and for whom to produce. Whereas in case of socialist economy or the socialist economy or the command economy generally the authority or the government means all the productive resources and generally they directs how the resources has to be used, what to produce and finally who is going to consume or who is going to purchase those product. The typical example is the China. Then in between these two these are two extreme one is capitalist economy entirely free, command economy that is or the socialist economy that is entirely restricted through the authority or through the government. So in between these two we get the mixed economy and mixed economy is the particularly here it is a mix of the capitalist economy and the socialist economy. Here the private sector is allowed to use free market within the broader political and economic policy framework, public sector reserves certain trade industry services or activity. So here some of the sector is guided by the government, restricted by the government, some of the sector is given to the private sector and they have to add or whatever the policy framework they have to add or what are the rules and regulation. So part of the sector goes to the private, part of the sector goes restricted by the government. The typical example is India, India is generally known for the kind of economic structure they follow that is mixed economy. So to summarize whatever we discussed today if we discuss that how generally the managerial economics emerge in the because the basis is the managerial decision problem and managerial decision problem can be solved with the help of the concept from economic theory that is from microeconomics, macroeconomics and using the decision tools that is statistical tool, mathematical tool and econometric tool and that generally used to solve the managerial decision problem and that way they get the optimal solution. Then we talked about what are the challenges the manager faces and from there if you look at the three basic problems that is what to produce, how to produce, whom to produce that is dealt with the three different kind of economy, three different kind of processes and also we talked about two basic assumption that is economic rationality and the setterie paribas and along with it that also the whatever the simple understanding of factor of production or the inputs what gets used in the production. So we will continue our discussion on reviewing the basic economic terms in the next session also. So next session we will talk about the opportunity cost, the importance of profit or the concept of profit that is economic profit, accounting profit and also the marginal and incremental analysis and finally, we will see the model on an economy, how there is a interrelationship between the sector, how the resources flow from one sector to another flow and how the income flow from the another from one sector of the economy to the another sector.


So hello and thank you for joining us today for today's public good app house demo event So joining me today. We have James Citron chief executive officer of pledge Today, we're gonna see how you can install and easily start fundraising through zoom and how your zoom meeting can become a fundraiser In minutes through the donations by pledge app It's an honor to be here and I'm excited to to share about the first donate button built for zoom So just a little bit about pledge. We are a totally free no contract Turnkey fundraising platform for any nonprofit and we've won a lot of exciting awards of the past year including fast companies most Innovative company for the launch of the first zoom donate button Which you're gonna actually see a sneak peek of in one minute. Some of you may be familiar with with pledge We have actually raised money for now over 33,000 nonprofits Have received funding through pledge Some of the products you may have seen or used are we have really easy to integrate donation forms and fundraising pages We'll talk about zoom in a minute But we actually won the first folks to launch text to donate for every nonprofit We launched Apple pay for charity in the US several years ago And so a huge growth in Apple pay and then a number of corporate partners We powered the fundraising line.  We're thinking What's going to happen to the world but also to nonprofits everywhere Analysts were predicting literally one third of nonprofits May go out of business during covid, you know, obviously every in person event cancelled Would donors still donate? What would happen? during covid I pledge we saw this Huge challenge the challenge for the world as an opportunity to rethink the future of fundraising And that led us to zoom and to virtual donation. We said Is there a way now that we're all connected virtually and this is the only way we're connected during covid Could we build donations seamlessly across every virtual event? That led us to first build a platform a virtual fundraising platform that works across twitch youtube and and every virtual fundraising and live streaming platform And ultimately to zoom And it was so fascinating when we first started talking to zoom a little over a year ago The number one literally the number one request from customers was why is it not easy to donate and zoom? I can donate I can do a fundraiser in facebook But why not zoom and that led to this big partnership with zoom where now Every nonprofit basically in the world we have 2.2 million nonprofits can now launch a free donate button zoom The thing that was amazing about the past let's call it 18 months or so Where it was scary for everyone, you know, no in-person events Let's pivot to virtual just so we can engage with our donors and try to continue fundraising. Well, what we found It was actually incredible for a number of organizations. We did 50 000 virtual fundraisers last year Raised tens of millions of dollars all virtually across all of the different platforms And these are just a handful of the big events that we did that some of you may have seen or participated in But the amazing thing for nonprofits is they pivoted to virtual one Many of them raised more money than ever before Nearly all of them reached a larger audience. You no longer have to Battle with travel times and traffic etc. You can reach anyone anywhere And many of our nonprofit partners actually had their best year ever last year And similarly this year because of the pivot to virtual we're going to hit play And let's turn on the audio here. You're going to actually watch a quick two-minute demo of the zoom donate button I'm going to talk over What you're seeing here. So at the bottom of everyone's zoom meeting You're going to see there's now an apps button Okay, and what's happening here is I just search for the pledge button Click install pledge Create a fundraiser and and that's me typing right there You can choose from any nonprofit in our database. That's 2.2 million. That's You know 2 million nonprofits globally not just everyone in the u.s Plug in a goal It our app automatically creates a fundraiser page. So beyond just zoom your fundraiser lives on It's got built-in text to donate So folks are on mobile and they're tuning into your virtual gala and they just want to text and donate With their thumbprint on apple pay donate in two seconds. They can And probably the most innovative feature everyone knows about these amazing virtual backgrounds on zoom So now with our donate button on zoom Literally as soon as a donor donates They actually get a special custom virtual background from you the nonprofit And built into the app are literally a bunch of templates or you can upload your own So here I am uploading one for once you planted an incredible environmental organization we've done a lot of work with And literally that's all I had to do to create a fundraiser in zoom it took Can take as little as 30 seconds you then paste it in chat like everyone's asking questions right now And once anyone clicks on a link in that chat they are actually going to have a donate button built into zoom like you see on the screen So you see my colleague Anna I know it's a little funny because you're seeing a video of me talking over the zoom app, but literally Anna Is just making a quick donation or that's me making a donation as well It's all in real time And you can set the virtual background and voila Now we've recreated that same experience of being an in-person event where when folks raise their hand and everyone wants to be a part of That fundraising that special moment We've brought that same experience now to a virtual experience a lot of what we did when we built this this zoom app was Taking the insights from 50 000 virtual events You know one of the biggest ones is if you put a link in chat and send everyone outside of zoom You're going to lose a bunch of your audience So now with everything built into zoom you're going to have the most donor participation possible You're going to raise more money more profitably because there's absolutely zero cost And for you as the nonprofit you see in real time how much money is raised You don't have to log into a another website and see oh did my big donor just donate Can I add offline donations all of that is built into zoom so in literally A handful of weeks launched we've seen nonprofits in 30 countries take advantage of this new functionality So we're really excited to launch this Zoom is an incredibly mission driven company. We've been working very closely with them to launch this functionality And they would love to see every nonprofit in the world is connecting with zoom really You know start successfully fundraising through this platform If you have any questions, please feel free to reach out to me I'll put my email in the chat and also a county link so you can you can book a time to see it But again, it's totally free. You can go to this URL today and set it up And we hope all of you have an incredible end of your giving I know it's a it's a stressful time, but we wish every nonprofit online the best the best end of your possible Thank you


Here's something else it has phases Venus ever had a visitor look through your telescope at Venus and say hey That looks like the moon. Well, here's a simple way to demonstrate why Tell your visitors. They're all viewing Venus from the earth. Here's a model Sun and here's a model Venus Venus orbits the Sun inside the Earth's orbit like this Watch how Venus is lit up as its orbits It has phases When you're showing Venus in the telescope place the ball in the same position relative to the light as Venus is to the Sun They will see the same amount of ball lit up as Venus


Welcome to the end-note spelling bee. In this miniseries, I'm following up on the question I asked in my video about spelling. What are your spelling pet peeves? Viewer Saxo Ungrammaticus, great username, called for reforming the spellings of sum, monk, and cum by putting the u back in them, which used to be there in Old English, and in any case more accurately reflects the pronunciation of those words, and also putting the i back in busy. To explain what happened here, I'm going to have to take us back to Phoenician and look at a number of letters, because there's a bit of a domino effect going on. Let's start with the letter F. I know it seems unrelated, but trust me, we'll get there. F traces its ancestry back to the Phoenician alphabet, and a character called ua, meaning peg. But it had a different sound then, more akin to modern English's w sound. This letter was initially borrowed into Greek, where it came to be called digama, because the symbol looked like two Greek gamma letters laid on top of each other. Greek eventually dropped that letter as the sound disappeared from the language, but not before it was passed on to the Etruscans, who also had that w sound. But when it came to Latin, the Romans needed a way to represent their f sound, so the letter F was reassigned. As for the w sound, well, the letter u did double duty, representing both the vowel u sound, and the consonant w sound, since both were very similarly made with the lips rounded. In fact, you may find it difficult to make the u sound without ending off with a w sound. Now, it's important to keep in mind that the Romans wrote that letter u in two ways. When inscribing on stone, it was formed with straight lines, like our modern letter v, but when it was written by pen or stylus, it was curved like our modern letter u. But both of these forms represented the same letter. The Romans didn't have a v sound, which is why Julius Caesar, sorry, Julius Kaiser actually said whenny-weedy-weaky. When the letters f and u came into Old English, a few modifications happened.  These two sounds are another pair of voiced and unvoiced sounds that are otherwise articulated in the exact same way, placing your teeth on your lower lip and blowing air through, what's called a labiodental fricative. This was generally not a problem in Old English since the phonetic environment determined which sound to make. For instance, between two voiced sounds, the f became a v. And we still see this today in such pairs as wife and wives, wolf and wolves. Though now we indicate that difference in pronunciation with a different spelling. But we still see traces of the letter f making a v sound in modern English. If you've ever wondered why the word of isn't spelled o-v, well, that's the reason. It's a holdover from the Old English spelling convention. As for the letter u, initially it was also used in English to make both the vowel and consonant sound as in Latin, and in post-classical Latin there eventually rose the convention of writing two u's in a row, a practice that later led to the letter w, now written with the pointed form of the letter, more like double v, which is what the letter is called in French, double v. But before these two u's were joined together into a new letter, the two u convention could lead to some cumbersome spellings, such as the Old English spelling of the word wolf, with three u's in a row. So the Anglo-Saxon scribes soon developed a new solution to the problem, adding in one of those Germanic runic characters, called win, to make the w sound. So u only had to represent the vowel. In a later spelling shift that doesn't indicate a change in pronunciation, but just a scribal convenience, since the Norman scribes didn't like using those runic characters, they dumped the win and went back to the w digraph. They were thus faced with the same problem again, made even harder to read in the scripts used at the time in which the letter u was made with two minims, that is two short vertical strokes that were identical to two letter i's. Indeed many letters were made with minims, such as n and m, making for very confusing manuscripts. So to avoid the problem, Norman scribes would often change the letter u in English words to the letter o, which is why wolf is now spelled with the letter o. Same goes for some from Old English sum, monk from Old English munuk, and cum from Old English kuman. Not all u's were changed, of course, only when it caused difficulty in reading because of the letters around the u. So Old English full is still spelled with a letter u in Modern English full, and there are some inconsistencies, such as Old English sunu becoming Modern English sun with an o, but sunu becoming sun with a u. Now something even more complex happened with the word busy, and again, I'll have to go back to Phoenician, and in fact that same letter wa. Because the Greeks actually got two letters out of wa, the digama making the consonant w sound that we saw earlier, and the upsilon for their u sound, a rounded front vowel that's made as if you were making an e sound, but rounding your lips as if you were making an u sound. By the way, the letter was originally just called u in Greek, but this was later expanded to upsilon, meaning simple or naked u, to distinguish it from similar sanding digraphs. This letter later passed into Etruscan and from there into the Roman alphabet, by which point the character looked variously like a u or v as we've already seen. The sound it represented was also slightly different. Latin didn't have that rounded front vowel, so the letter referred to their u sound. But as the Romans began to borrow Greek vocabulary, they found they needed a letter to represent that Greek upsilon sound, so they simply re-borrowed the letter in the form that it had in Athenian Greek at the time, which was where we got the letter y from. The Romans called it e greica, meaning the Greek I, and that's still what it's called in French, e grec, and it was initially only used for words borrowed from Greek. But eventually, the pronunciation of the letter came to be indistinguishable from the letter I, and in medieval Latin it was sometimes used interchangeably with the letter I, especially to deal with that same minimum problem we talked about before. So for instance, the word in William, meaning impassable, and made up entirely of minims, could instead be written with a y in place of an I. When the alphabet was adapted for Old English, they found the letter y useful, because like Greek, Old English had that rounded front vowel. And here's where we finally get to the word busy, because Old English busy was sometimes written with a y, and sometimes with an I representing different regional pronunciations. The e sound was probably the original stem vowel sound, but in the late West Saxon dialect, this seems to have become rounded to the y sound. As Old English became Middle English, we ended up with the u spelling, reflecting that rounded variant found in West Midland and Southern dialects, but the I pronunciation from the East Midland dialect. A thoroughly confusing business. I'll be continuing to respond to your comments and suggestions in more spelling b videos intermittently for the next while in between other main videos. Thanks for all the responses which keep coming in. As always, you can hear even more etymology and history, as well as interviews with a wide range of fascinating people on the endless not podcast available on all the major podcast platforms, as well as our other YouTube channel. Thanks for watching.


Thank you Thank you so much Thank you for the introduction that looks that sounds very serious. Actually, my talk is really Answering just one question that we are constantly getting asked at the booth And I guess everybody has here still in the crowd. What is Microsoft doing at the open source conference? Okay, so that's 20 minutes to answer that question And I will I hope that by the end of my presentation You will finally understand why we are here and by the way, please feel free to come talk to us At the stand at the booth today tomorrow with me and my colleagues So I will actually start by saying like my own personal connection to open source Is relatively old I started working with open source with Linux specifically many years ago I was lecture at the university. I was PhD student and lecture that was before Microsoft And then I went to the dark side and that was almost 15 years ago So I'm as much Kind of blue blood Microsoft as you can find in this company and yet here I am right and my role is open source Lee so yeah, I kind of I I'm pretty sure you will be interested in our story. I will start by you know Talking about importance of open source in general There are a couple of things here on this slide on the next slide about the role of open source in the digital Transformation so all the companies in the world whether they and software or any other business, right? They are really thinking about how they can make sure that they Continue innovating in whatever they are doing and so there is there these wonderful Piece of research that was done by Forrester Last year and they're talking about the importance of open source and that is powers enterprise digital transformation And I really like this It's a really perfect English that failure to fully consider open source is unforgivably negligent I mean these I really love like I would never be able to come up with such a beautiful English But okay. Well, it's really it's really happening. It's not just in software companies You know a couple of examples on the next slide Goldman Sachs or Safeway, right? Disney I mean not exactly Software development of house even though you can argue they are these days, right? I mean look at how they are doing all their animation right now It's all in the end of the day computer software industry But they are really saying what you know because it's kind of a fine print here So you cannot really read but it's from their web pages like open source software is important to Walt Disney Company So it's important to everyone right all walks of life software companies hardware companies Non-IT companies all together and this is important for you if you want to continue innovating and at some point of time we actually Realize that also at Microsoft so it's really if you come to think of that we are going through a big transformation of our own and We actually Really want to make sure that we are empowering every person every organization and planet to achieve more and that means many different things And so that means Empowering like building the best platforms and taking advantage of all sorts of different innovations regardless of whether they Came from within organization or from outside and this is really critical So if you're looking today, it's really all about openness So we really want to embrace We really understand that we cannot create even though Microsoft has one of the biggest R&D budgets on the planet You know bigger than some of the countries, but it's still not everything right So you really want to make sure that you are capturing everything wherever it comes from and Just to get a little bit ahead of myself The reality is that's already that's already happening and it's already being noticed right so it's this actually an interesting article from Fortune magazine, so not even an IT publication and you will be able to find many more of these days I mean it's really becomes kind of a Bread and butter for journalists writing about Microsoft and they're talking about it's really interesting like essentially This is a money publication, right and they're talking about open company. They're talking about cloud They're talking about hybrid strategy. So essentially they're talking about the strategy of Microsoft as a software company Right, so this is and I think it's really connected to a large extent with a new CEO that we have Satya Nandela Who started these changing or kind of accelerated this change that has been already happening earlier? But I think it really came to the four in the last two years. So however, it hasn't started like From from zero so Microsoft has been involved with open source for a long time Actually, my personal first connection to open source and to Microsoft was when I was still in the University Actually, my first connection to Microsoft was Microsoft research and they were doing stuff around Something called shared source at the time. So they were coming up with the idea of how we can try to make Windows source available for people who are Want to study operating systems? So this is actually how I got introduced to Microsoft in the first place because I was teaching operating system course essentially at the time I know was guess what using Linux, right? So and That's continued. So the very first things were in research They were in connecting to the open source companies and platforms They were talking about how we can make sure that open source software can talk to Microsoft software But then it really became you can see here on the timeline We got really involved in our open source foundations and also we can continue contributing code to open source Projects so today we really I will show you some of these things But we really following the following approach and let me build the whole slide. So We really want to make sure that we enable Linux and open source to be first-class citizens of Microsoft platform So essentially whatever you're doing on Linux, we should be able to support We should be able to run on our public cloud on Asia And we we need to be able to also integrate and interoperate with that. Okay We're also releasing open source in open source format our own products Again, this is not something new but we are doing that on much bigger scale than we ever did before So for example today if you are in Microsoft in the development team in Redmond and you are starting a new project One of the first questions I will ask you is is this project going to be available in open source? And if not, why not right so there must be a really strong business reason not to release an open source in the past It was the opposite right so and finally we also participate in ecosystem not just conferences like these but also the standards group and Foundations that support the development or standards for interoperability We also work with the partners that means that we're talking to the partners that Microsoft probably never really talked to in the past Right, so we had our own Nice ecosystem, but if you want to work with the open source community that also means different vendors different ISVs different System integrators so all these partners are really new to us. So the next slide is actually kind of List of some of our quote-at-quote achievements that we had an open source so far So one of the things on the left side we released sequel server on Linux So you can actually download it today and run it It is available as a public preview and we are launching that in just a matter of a couple of weeks and You can actually See it's one of the first Microsoft first party products that we made available on Linux, right? So we already did something similar with visual studio would released a part of visual studio That you can run on Linux. You can run on Mac. You can run in the browser actually But like these really like a major server product that we have to be available on Linux This is the first time so We are really proud of that. I'm pretty sure you also heard about Windows subsystem for Linux so essentially on Windows 10 you can now run bash and you know execute whatever commons From the shell We signed a couple of Agreements with different companies not just right that we also partner with Susie We actually were trying to work with all the major Linux vendors At the same time still the thing that a Load of our engagement is sent around cloud is sent around Asia we Microsoft are not Linux distribution Company like there is no Microsoft Linux. Okay. I don't expect one This is not what we do There are other companies that are doing that and are doing great and then been doing that for many years However, what we want to make sure is that these Linux distributions that we will be able to run on our public cloud infrastructure Just as good as they are running on premises So essentially our promise to to you as a developer or to Linux distribution companies to the vendors that if you if it runs on Linux we can run it on Asia today So like kind of no questions asked right. So this is a bold promise And there's been a lot of work involved in that. However, we're also seeing the dividends So if you're looking at Asia marketplace, so the way to distribute solutions on Asia You will see that more than 60% of images actual Linux open source So that's I can tell this is not what Microsoft initially expected when we launched Asia, right? And there is still this perception that Asia is kind of windows only public cloud And so this is something that we need to dispel So you can run Linux and this is just as well a public first-class citizen on this platform and Today one of the other things that you will see Lee I will also build a couple of other points. So we have More like close to 10,000 open source companies used I have 6,000 employees working on open source directly like on the daily basis If you just count everything that Microsoft developers are using like open source that number will be way higher It probably will be pretty much every single developer that we use at Microsoft today But there are also people who are dedicated to just supporting and building developing open source projects Okay, so we also released more than 3,000 open source project as a result of that Sometimes we are getting like ourselves to quite new new grounds, right? So these are article published on ZD net last September study they did on github and guess who is at the top of the By number of contributors for the projects To be perfectly honest, I think it's kind of overblown if you really look carefully on the right like Our friends from Google and you know if they would just count Google and Angular together There will still be a number one, but the point is different It's actually can you imagine these things happening five years ago and Me coming from you know Microsoft for you know spending like almost my all grown-up life in these companies I couldn't okay, so this is really new Microsoft. These not your dad's Microsoft and now this is really That that's even you know fresher news and That you would never believe how many jokes about Microsoft and how freezing over I received that day So because Microsoft became a platinum sponsor for the Linux Foundation and again This is something unthinkable for Microsoft to support essentially what's Built in the Charter of Linux Foundation. It's one of the major purposes to support the work of Lena's torals, right? So for Microsoft to become a platinum sponsor get a seat on the board of directors. That's pretty unusual I would say right now as I was saying a lot of that really boils down to our public cloud platform and this is Why Microsoft is in this business so and this is also why Microsoft is no longer Fighting with the open source software no longer calling it a cancer or whatever we were doing in the past 15 years I think the major really difference is that Microsoft has finally found a way to Be part of that process Microsoft has finally found a way to monetize Linux and open source just like everybody else sitting here and over in the audience hopefully succeeded to do so The what we found out what we realized is that whenever you're running something in a cloud It absolutely doesn't matter if you're running Linux on Windows because it's not about the licensing costs, right? It's about services. It's about utilities. It's about being able to charge your consumers by the hour Right and this is for us in Microsoft. This is the answer today It's not the only answer and I was showing it to you sequel server on Linux that net Core on Linux means that we will be also releasing our first party products there But at the very beginning at least we want to make sure that we will run your Linux Project and infrastructure perfectly on Asia. So a couple words about Asia why we think it's you know It's one of the biggest computing infrastructures in the world I think there are really literally only a couple of handful of companies that invested so much in the cloud infrastructure worldwide and It's going to stay like that and they're not going to be 10 different public cloud companies few years down the road There might be three. There might be I know two or four or whatever You know, but it's literally the investment is so big that only a few companies will be able to afford it On a global scale and we have this scale. We already have this game I mean Microsoft had this global scale. I don't 15 20 years ago and it's really If you're looking at the number of transactions that we are running or the Number of cores that we are running in Asia. It's amazing And we are really having more than 90% of the biggest company in the world already using Asia and that number grows You know like half a year ago when I was showing this slide. It was 85% So literally all the companies the world are getting these transformation to the cloud They're really buying into that concept. They start using that on a daily basis and to support that growth We built one of the biggest infrastructure and you actually see like a some representation there on the screen It's by the number of regions that are available to developers geographically. We're number one By far actually so we have more than twice the number of AWS regions I'm not saying by course by course probably they're bigger Granted But if you're looking both for the global footprint, you will not find anything better than Asia today And by the way, we're still growing We just launched last month new data center in Korea actual two data centers the region so we have in Seoul and Busan and We will be continue doing that in other countries as well so just to get to the conclusion and I'm already close to running out of time We really are all in on the cloud We are also all in on the open source because we see that this is the way to the future We want to be part of these open source ecosystem not only as a consumer, but also as a contributor and We we think we already Achieved a lot in the past several years and the world noticed again couple of quotes that I'm not even going to read it, but essentially Probably the biggest impact. I mean for me personally, I know as a Microsoft shareholder This is the biggest impact to know a stock price. Okay, so It's really in the past few years. We're going on these trajectory that is really positive um To conclude a couple of links We have a wonderful website Microsoft.com open source easy to remember We also have a couple of social media platforms. So we are on Twitter. We are on Facebook Please follow us on Twitter open for bees a pack and the same of Facebook If you are here at the conference come to our booth after the presentation Make sure if you're interested in Asia, you there is a wonderful way to get free Asia subscription. There is a link at the bottom so For students developers for anybody actually most of my demos. I'm doing using these free Asia subscriptions it gives you more than enough to to experiment with Asia to get the idea of how it works and Yeah, so with that actually we have three minutes for questions. So I'm ready to answer and by the way if you're If you're too shy or whatever if you cannot get to our booth after that, even though it's just right outside There is my email Twitter handle Find me on LinkedIn. We also have LinkedIn as a one. It's a wonderful social platform as well questions Come on. So as The cloud Microsoft cloud is running on Linux. Why not windows? again, can you So This is this means that the Microsoft has lost the battle with Linux and now collaborating with them Sorry Can just speak a little close to the microphone because I barely here. Okay, so The Microsoft cloud is running on Linux, right? Yes. So no not really but okay. It runs on Linux, too Yeah, so does this mean that Microsoft has lose the battle with Linux and now they are Trying to collaborate with Linux We tried to collaborate with everybody. Okay, so just to be very clear We can still run windows on our cloud. It's great. It's where we started You can run Linux on Azure as well So and we want to make sure that actually whatever like the whole landscape if you're thinking, I know Red Hat or Susie or PHP. No GS. Whatever you're running. We want to be able to run it on Azure We also by the way, I didn't talk about it in this presentation for the lack of time But we can perfectly well manage you infrastructure as well or you can manage your infrastructure So we have tools like I know system center or operation management suite where you can manage the whole infrastructure again regardless whether it's on Windows whether it's on Linux whether it's Android phones or iPhones essentially, this is what we do. We really want to make sure that we are kind of platform agnostic in the new world Audrey of the dancers. Yep. Yeah, how does the Microsoft movement do open source impact the enterprise license agreement? So the thing is that it's a great question. First of all, I would answer you with a question How does it? open source impact enterprise agreements for red hat I For the last 20 years. I work in the corporation I always wanted to cut our license pens and it seems that Microsoft is always ahead of me whenever I said, let's do Linux Microsoft now is doing Linux. No, no We don't do Linux. No, if you're buying like Subscription right if you're buying support, it will not be Microsoft Okay, so you will still have to talk to red hat or Susie or whoever these provider for Linux now It's it's slightly different. What I mean to say is that it's really It almost doesn't matter in another day What we are seeing is a big trend from on premises to the cloud computing today and there even the whole point of enterprise agreement In a way, it's kind of becomes a moot point So yeah, you can still sign it. You can even get the benefit by prepayment and so on so forth But this is more about pay as what you consume rather than paying for the licenses It's not really about the licenses anymore. And so that's not answer number one and answer number two that for the introduction of Linux didn't do away with the enterprise Pricing or licensing just look at the red hat. They're two billion dollar company and they're selling essentially what's free, right? So I don't think that that Really has any significant impact on the story the cloud computing is much bigger. Thank you All right, I was just shown that I'm out of time. So if you have any questions, I'm just outside Thank you for your attention and have a great conference All right. Thank you very much