Truth that Contacting of Different Qualities Releases Energy (1)

In Chapter 1, we learned relationship of truth and its expression. What is happening now is an expression of truth. Truth exists, but truth is invisible to the eye. Its location is also indiscernible, yet it exists. The visible social phenomena occurring now are expressions of truth, meaning the corresponding truth does exist. One such truth is in the title.
I will explain truth that contacting between different qualities releases energy with an easy-to-understand example.
This explanation would be straightforward and easy to understand if you grasped thermodynamics. However, thermodynamics is not easy to understand. Therefore, I change the order of the explanation and choose an example so that you feel the truth more intuitively. The example is mixing of hot water and cold water. Even so, I incorporate some concepts of thermodynamics into the explanation. This is to gradually get accustomed to the thinking of thermodynamics.
There was the problem example of mixing water when I was in elementary school.
I remember the problem. The problem was “ what temperature it would be when mixing hot water and cold water. I will reproduce a similar problem, owing to my memory. After this example of water, I will introduce an example of electrical contacting. Once you understand these, you should be able to grasp the meaning of truth in this second chapter.

Example 1 of Contacting of Different qualities
There is a problem of elementary school: If you mix equal amounts of 80°C water and 40°C water, what will be the temperature of the mixed water?
Elementary school student's answer:
The temperature is 60℃　that is middle temperature　between 80℃ and 40℃（seems correct, but actually not correct)
Correct answer:
Depending on how they mix, energy is released to the surroundings, resulting in a temperature between 60°C and 56°C.

When I was an elementary school student, I didn't know how to find the answer. No one in the class could answer it.
I remember the teacher explained how to answer it, and I think I had a simple doubt about how to mix them.

Now, I realize that it was natural not to be able to find the answer if I thought about how to mix them.
The temperature of 56°C was calculated by considering the energy released to the surroundings.

The calculated value is a theoretical value that follows a unique path. There is a reason for calling it a unique path. When mixing, instead of doing it abruptly and violently, it can be assumed that heat is transferred from the hot water to the cold water in a reversible manner over time. At this case, there is only one reversible path.

Reversible path implies that it takes an infinite amount of time to transfer heat. Reversibility also implies that there are no losses. Losses refer to energy that cannot be recovered.

Here, we consider the ideal of transferring heat through an equilibrium state that can return to its original state without any loss. Everyone knows from experience that heat does not move from a low temperature to a high temperature. Therefore, if heat moves from a high temperature to a low temperature, it is not in equilibrium.

In reality, it is impossible to transfer heat while maintaining an equilibrium state. However, an ideal model can be considered where heat is transferred by approaching equilibrium as closely as possible over an infinite amount of time.

For example, in the earlier example of mixing water, it would involve a method of preserving the convective energy generated when the water mixes.

Let's consider placing a propeller generator within the convection currents that occur when hot and cold water mix, and storing the convective energy in a battery.

There is frictional energy present when the fluid moves, caused by the rubbing of the fluid. Let's assume this frictional energy can also be stored as work energy. Additionally, the vibrational energy generated by the movement of the water can be stored in some manner. In other words, we assume that these kinetic energies generated during mixing can be preserved for reuse.

The stored energy originally existed as the thermal energy of the water. Since it was released through the motion during mixing, from the perspective of the original water, this is the energy that the water has lost.

The mixed water loses energy equivalent to the energy released to the outside. As a result, the temperature of the mixed water decreases by the degree of energy lost. This qualitative idea is not difficult to grasp intuitively. This is why the temperature of the mixed water is 56°C instead of 60°C.
While the calculation of this temperature is not necessary to know here, some may be curious. For those interested, I will present a calculation using the thermodynamic concept of entropy in the next column.

[ Author : Y. F. ]