7. Energy and Metabolism
Laws of Thermodynamics
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In this video we're going to introduce the second law of thermodynamics. And so the second law of thermodynamics can actually be stated in many different ways. And so it's possible that your professor or your textbook might state the second law of thermodynamics in a different way. But really, all the second law of thermodynamics is trying to say is that 100% efficient energy conversion is impossible since heat energy is going to be lost with every energy transfer. And this is going to lead to the increase of the overall universal entropy. And so heat is going to be defined as a form of kinetic energy that is going to be transferred between 2 objects with different temperatures. Let's take a look at our example down below at the second law of thermodynamics to get a better understanding of the second law of thermodynamics. And so notice that we're showing you a similar process to our last lesson video on the first law of thermodynamics. And so you can see that, the sun is really going to be the, the energy provider where most of the energy is going to originate from, from life. And so you can see that the energy transfer here from solar energy to plants is going to be accompanied by a loss of heat. And so with every energy transfer, there's going to be some of the energy that is lost as heat. And so there's not a 100% efficient energy conversion. Some of the energy is lost as heat and that heat is not going to be a usable form of energy by the organism. And the same goes between, when an organism might eat, you know, the leaf. The energy transfer here is gonna be accompanied by a loss of heat. And the same goes when the fox here eats the mouse. There's gonna be a transfer of energy, but some of the energy is going to be lost in the form of heat. And this heat that is being lost with every energy transfer is going to lead to the increase in the entropy of the universe. And so the entropy of the universe is always going to be increasing with every energy transfer. This here is really what the second law of thermodynamics is referring to, the increasing of universal entropy with every energy transfer. And so this here concludes our introduction to the second law of thermodynamics and we'll be able to apply some of the concepts that we've learned here as we move forward in our course. So I'll see you all in our next video.
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