Yu Chol Min, a researcher at the Faculty of Metal Engineering, has been using anecdotes and practical data in physical chemistry to help his students have a better understanding of concepts and formulae given in the lectures. As a result, they have been able to grasp the main points of his lectures and to improve their practical abilities.
Physical chemistry is a subject which deals with the relation between physical and chemical phenomena occurring in metallurgical processes, and its contents are mostly related to abstraction and theory. For this reason, if the lecture is focused on explanation of theories, derivation of formulas or calculation, students will find it difficult to have a notion of what they are learning and it may lead to the decrease in their enthusiasm for study.
Therefore, he decided to invent some methods to stimulate students’ interest and enthusiasm and to provide them with a vivid notion.
To start with, he used the method of telling anecdotes about famous scientists to improve the understanding of concepts and formulas given in the lectures.
Even a single concept, a law or a formula came into being through the efforts of many scientists and it involved corresponding anecdotes.
If students are told certain anecdotes related to a notion or a formula, they can get to know about the history and mysterious background of them and understand them more easily.
For instance, he used the following anecdote in the lecture on the second law of thermodynamics.
The efficiency of the steam engine made by Watt in 1770s was less than 10% and it wasted a large amount of heat energy. So scientists tried to make a perpetual machine which would convert the whole amount of heat energy provided by a single heat source to completely different kind of energy.
“Zero motor” which a scientist attempted to design is a typical example. According to research, if the heat diffused in the process of lowering the temperature of about 109km3 of the sea water on the earth by 0.25℃ was converted into energy, 1015kW of electrical energy would be produced, which is said to be quite enough for the whole world to use for as long as a thousand years.
He wondered if he could get mechanical energy from the steam released when liquid ammonia in a cylinder was gasified by such a huge amount of heat energy, and liquefy it back. Then, he was planning to make a motor which produces energy constantly through this cyclic process. However, his idea turned out to impossible and his effort was in vain since gasified ammonia can never be liquefied on its own.
In addition to him, many scientists attempted to make a perpetual machine for many years, but they all failed. In the meantime, an idea came into their minds. They wondered if the impossibility of making a perpetual machine might serve as a kind of law that explains the natural world. That was formulated as the second law of thermodynamics in the middle of the 19th century.
Such a historical fact related to a perpetual machine stimulated students’ interest in the second law of thermodynamics so they could have a scientific understanding of what a perpetual machine was and why it was impossible to make it.
Next, he led students to grasp the gist of the lecture by themselves and to improve their practical abilities by giving a scientific solution to the problems they usually come across in their daily life.
The examples closely connected to new knowledge and often seen in daily lives could improve their faculties of inquiry and creation and make them realize the significance and value of their knowledge by leading them to the world of physical chemistry.
We can take the lecture on the kinetics of heterogeneous reaction as an example.
Explaining the kinetic difference between homogeneous and heterogeneous reactions like solid-gas, solid-liquid and solid-solid, he presented a question, “Why do they burn powdered coal instead of lump coal in the boilers at thermal power plants?”. Then the students answered that the combustion of powdered coal is faster than that of lump coal because the surface area of powdered coal is larger.
He continued explaining that powdered coal flew about in rotary kilns, which resulted in a great loss, and that it raised the issue of forming it into small grains. Then he set forth a question for this and led them to its solution.
Therefore, the students could have chances to apply what they had learnt to practice and try harder to acquire more knowledge.
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