So now that we know that thermodynamics is the study of energy and energy transfers, in this video, we're going to introduce the first law of thermodynamics. And so the first law of thermodynamics basically says that energy can be transferred from one substance to another substance, and energy can also be transformed from one form into another form. But energy cannot be created or destroyed. And so this is why the first law of thermodynamics is also known as the principle of conservation of energy. And this is, again, because the total amount of energy in the universe is conserved, process is going to be equal to the total amount of energy after a process since energy is not created or destroyed. Again, energy can be transferred from one substance to another, and it can be transformed from one version of energy into a different version of energy, such as kinetic energy into potential energy and vice versa. But again, energy cannot be created or destroyed, and this is basically what the first law of thermodynamics says. So let's take a look at our image down below to get a better feel for this first law of thermodynamics. And so notice that in this image over here, we're showing you a plant cell over here on the far left, and zooming in here, you can see that we have our plant, and inside of the plant we have this chloroplast, which recall performs photosynthesis. And then over here on the right-hand side, we're showing you an animal cell right here, and we're zooming into this little bunny rabbit, which is an animal. And you can see that the bunny here we're zooming into this mitochondria here which performs cellular respiration. Also notice that we have the sun here, and the sun is really where most of the energy of life is going to originate from. And so the sun's energy, its solar energy, can be captured by photosynthetic organisms such as plants that perform photosynthesis, and photosynthesis is capable of transforming the solar energy into chemical energy of glucose. It also creates some oxygen in the process. But what you can see is that energy is being transferred from the sun and being transferred from the sun to create a different type of energy, chemical energy here. And so what we're saying is that energy is transferred, but once again, it cannot be created or destroyed. Now, the animal cell over here, the little bunny rabbit is able to eat the leaves and eat the plant. And when it does that, it can obtain the energy of the glucose. And then it can use the energy of the glucose to create a different type of energy, ATP, energy that can be used by the cell. And so ultimately, what we're seeing is that energy can originate from the sun. It can be converted into chemical energy of glucose. It can be transferred to other organisms such as little bunny rabbits that can eat them. And then of course, the bunny rabbits, when the bunny rabbits pass away and also when they conduct cellular respiration, they can transfer their nutrient over back to plants. And so, they're able to create carbon dioxide and water that photosynthesis is able to take advantage of. And so here what we're saying is that the first law of thermodynamics is that energy can be transferred and transformed into different versions, but once again, it cannot be created or destroyed. And so you can see the energy here is flowing in this direction, and it just cycles between different forms, but it's never created or destroyed. And so this here concludes our brief introduction to the first law of thermodynamics, and we'll be able to get a little bit of practice as we move forward in our course. So I'll see you all in our next video.