 Welcome to Heat Transfer. What I'm going to be doing in this course is covering the topic called heat transfer. And what we'll begin by doing is taking a look at the different forms of heat transfer that exist. And essentially what heat transfer is, it's the process of energy exchange or energy and transit due to a temperature difference. And so what we're going to be doing in this course is we're going to be studying heat transfer and there are three main types of heat transfer, modes of heat transfer. We're going to spend a lot of time looking at two of those being conduction and convection. There's also radiation. We'll look at it, but not in the same level of detail as we will with conduction and convection. So let's take a look at the three types of heat transfer. Okay, the first type of heat transfer we're going to take a look at is conduction. And conduction occurs in solids. And what is driving conduction are temperature differentials. And so here we have a case or a scenario where we're looking at a solid and we have T1 on one side and T2 on the other side. And if it happens that T1, temperature 1 is greater than temperature 2, the heat is going to flow from the hotter temperature to the colder temperature. So that's a pretty natural process that we're all familiar with. But in this, what we would then do is we would sketch the heat transfer and we draw it with a little cue. That's what we'll be doing in this course. We'll use a little cue to denote heat transfer and we'll talk about the units. The units are joules per second or watts, but we'll look at that a little bit in more detail later on in this lecture. So that's the first form of heat transfer. The next form is convection. So here we're taking a look at a schematic with convective heat transfer. And when you have convective heat transfer, there's usually, well, there will be a fluid involved. There will be a fluid and a solid interface. And so what will happen is the solid will be at a different temperature from the fluid. And you could either have the solid hotter or cooler than the fluid. But in this case that we're looking at here, we're saying that the solid is hotter than the fluid temperature. So in this case, what would happen is heat would flow from the solid out into the fluid. And we would draw our convective heat transfer going in the direction into the fluid. So in this case, the solid would be heating the fluid, the last form of heat transfer. And it's one that is very different from conduction or convection, and that is radiation. Now when we're dealing with radiation, what happens is objects radiate and they absorb energy. And typically in heat transfer, we're looking at energy in the part of the spectrum referred to as the infrared. But when we look at this, what happens is energy is being emitted by an object. And so it would be radiating, and we will call the radiative heat transfer coming off Q1. And this object down here can be radiating as well, and that would be Q2. So when we look at radiation heat transfer, it comes down to being a balance between the amount that is emitted and the amount that is absorbed. And we will look a little bit at radiation, but not in the same level of detail as we will for conduction and convection. So those are the three forms of heat transfer that we'll be looking at in this course, the three forms of heat transfer that exist. And what we'll do in the next segment is we'll take a look at how heat transfer relates to fluid mechanics and thermodynamics.