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In total, there are four laws of thermodynamics. But in this topic, we will only deal with the second law as it is the point of focus. The second law of thermodynamics states that the overall entropy of a certain isolated system can and will never decrease. The second law of thermodynamics proved to be an important part of the history of physics and is regarded as the axiom of thermodynamics. The first formulation of the second law of thermodynamics was based on the caloric theory. It is also known as Carnot’s theorem, named after Sadi Carnot. He was a French scientist who first experimented in 1824. While Carnot helped in developing the basic structure, there was another scientist who defined the second law of thermodynamics.
Rudolph Clausius, a German scientist, was the first one to define the second law of thermodynamics. In his statement called the ‘Clausius Statement’ he said that heat trapped within a body can be passed on to another body, which is cold, without any change taking place. In simpler words, heat can only be transferred when certain changes take place. Rudolph Clausius released his statement in the 1850s.
Definition of Second Law of Thermodynamics
The second law of thermodynamics, in a thermodynamic system, does the work of establishing an entropy concept of a physical property. 2nd Law of thermodynamics can be used for several purposes. It can also be used to define the thermodynamic temperature concept, even though this particular concept falls under the zeroth law of thermodynamics. Apart from Sadi Carnot and Rudolph Clausius, other scientists like Max Planck, Lord Kelvin, who was responsible for the Kelvin Planck Statement, which stated; it is not possible for any device that runs on the cycle to gain heat from a single reserve and in turn produce a net amount of energy. The 2nd law of thermodynamics is not only limited to the students of physics. People pursuing economics also need to study the law in Environmental Economics.
Applications of the 2nd law of thermodynamics
The applications of the second law of thermodynamics are as follows:
- According to this law, the transfer of heat takes place between a hot object and a cold object. This application of the second law of thermodynamics is used in almost every heat engine cycle. Starting with Otto and diesel to other types of engines used fuels. Due to this law, we get to enjoy the advancement of vehicles.
- Reversed Carnot Cycle is an important part of the second law of thermodynamics. The Reversed Carnot Cycle theory is used in heat pumps and refrigerators. For transferring heat from a lower temperature body to a higher temperature body, the external work needs to be applied. In the Carnot Cycle, the transfer of heat from a higher temperature object to a lower temperature object produces work, but in the reverse Carnot Cycle, it is vice versa.
In both refrigerators and air conditioners, the heat from a warm object is not transferred magically. The heat flow takes place in a decreasing tendency that is from high to low temperature. In a refrigerator this happens in a reverse manner that is from low to high temperature.
In the case of a heat pump, the heat is trapped from the atmosphere and released in a room to make it warm in the winter season. It is seen that in both cases, there is always external work. In this case, it is electricity.
- During a public gathering or crowded room, people start to perspire. It is due to the person feeling hot. The body is being transferred into the sweat and the sweat will evaporate into the atmosphere and make the person cool. This follows the law of the first and second laws of thermodynamics. People should always keep in mind that none of the heat is lost. It is only being transferred.
The second law of thermodynamics example
One of the most common examples of the second law of thermodynamics is air leaking from balloons. Children love to play with balloons. After their parents buy them a balloon, they become overjoyed. But after a couple of days pass away, their smiling face turns into a frowning face. It is due to the balloon getting deflated slowly. It falls under the second law of thermodynamics. The air is forcefully put inside the balloon. It follows the entropy concept and is a spontaneous process example.
Other examples of the second law of thermodynamics include a hot cup of coffee becoming cold, two separate gases getting mixed after a certain time, melting of ice automatically, etc.
Conclusion
The laws of thermodynamics have been an integral part of us from the very beginning. It is needless to say that the second law of thermodynamics is one of the main laws. Many of the things we use in our daily lives follow the second law of thermodynamics. Most of the details about the 2nd law of thermodynamics are covered in the above article, along with a few FAQs.
