 Hello and welcome back to another episode of Physics Partner. In today's video, we are going to discuss 2nd law of thermodynamics. We will also be exploring the concept and real life applications of this fundamental law that governs the natural world. Let's start by understanding the basic concept of the 2nd law of thermodynamics. Simply put, this law states that the total entropy of a closed system always increases over time. Entropy is a major of quality of energy in the sense that the lower the entropy, the higher the quality. Entropy is a major of the degree of disorder, randomness or cohesion in the system. Hence, it implies that over time, the degree of disorder in any system will always increase. In simple words, the law explained that an isolated system's entropy will never decrease over time. The 2nd law clearly explained that it is impossible to convert heat energy to mechanical energy with 100% efficiency. For example, if you look at the piston in an engine, the gas is heated to increase its pressure and drive the piston. However, even as the piston moves, there is always some leftover heat in the gas that cannot be used for carry out any other work. Heat is wasted and it has to be discarded. In this case, it is done by transferring it to a heat sink or in the case of the car engine. Waste heat is discarded by exhausting the used fuel and air mixture to the atmosphere. Additionally, heat generated from friction that is generally unusable should also be removed from the system. Now you may be wondering, what does this law have to do with the real world? Well, the 2nd law of thermodynamics play a vital role in almost every aspect of our daily lives. From energy production to cooking. One of the most significant applications of this law is in energy production. For example, electricity is usually produced in power plants by burning fossil fuels like coal, oil or natural gas. This process releases heat which is then used to generate steam that drives turbines, producing electricity. However, the process is not 100% efficient. Some of the energy is lost as heat which is released into the environment and since heat always flow from region of high temperature to region of low temperature, the potential of producing electricity diminishes further. This loss of energy is a classical example of the 2nd law of thermodynamics. Another example of 2nd law of thermodynamics in action is cooking. Every time you cook food, you are creating a closed system. And as you know from the law, the total entropy within the system will always increase. The heat applied to the food causes its molecule to move faster and more energetically. Increasing the entropy and the longer it is cooked, the more disordered it becomes. In a nutshell, the 2nd law of thermodynamics is one of the most fundamental laws of the natural world and its effects are undeniable in everything we do. It is fundamental in our understanding of energy, physics and even cooking.