In this video, we're going to begin our lesson on the thermal properties of water. And so to understand the thermal properties of water, we need to understand kinetic energy. And so kinetic energy is really just a measure of energy in the form of motion. And so if substances are moving, that means that they have kinetic energy. It's really the energy of motion. Now, temperature is a term that we've all heard before in our past, and really temperature is just defined as the average kinetic energy of molecules in a solution or in a sample. And so "average" here is really the keyword. And so if a sample has a really, really high temperature, what that means is that the molecules in that sample have a high average motion. And so notice that these molecules in this sample have large arrows to represent the high average motion that they have. And so they're moving around a lot and very fast. Now, low temperature, on the other hand, of course, means that the samples, the molecules in that sample have low average motion. And so notice that these molecules have small arrows to represent that they're moving very slowly, in comparison to the high temperature samples.
Temperature is not to be confused with thermal energy. So once again, temperature is the average kinetic energy. However, thermal energy is the total kinetic energy of molecules that's transferred specifically as heat. And so if we take a look at our image down below here on the right-hand side we can distinguish between temperature and thermal energy. And so notice that we're comparing two samples, a hot coffee pot on the left-hand side with a large swimming pool on the right-hand side. Now of course the hot coffee pot if we measure its temperature, it's going to be quite high. It's going to have a high temperature because the average kinetic energy, in these molecules is really high. They're moving really fast over here, on average. And of course, the swimming pool over here is going to have low temperature. It's going to be quite cool if you were to jump into that swimming pool, and that's because the molecules, on average, have low temperature. However, if we focus on the thermal energy what we'll find is that the hot coffee pot, because it has such a small volume, it actually has a lower thermal energy in comparison to the swimming pool over here which has a much larger volume. And so the swimming pool over here, because it has so many more molecules, the total energy of all these molecules adds up to be more energy than the molecules over here in the hot coffee pot. And so that means that the swimming pool, simply because it has a much larger volume, has a higher thermal energy. More total energy over here in the swimming pool because it has simply a lot more molecules. And the hot coffee pot, even though on average they have a higher temperature, more motion, in total there's a lot lower thermal energy in the hot coffee pot because it has such a small volume in comparison to this large swimming pool.
This here concludes our introduction to kinetic energy, temperature, and thermal energy, and as we move forward in this lesson, we'll talk more specifically about water's thermal property. So I'll see you all in our next video.