In middle school, we all learned about vaporization, liquefaction, sublimation, condensation and other changes in physical state. One of the scientists that Tadpole Jun wants to introduce to you today is a scientist who studies the change of state of matter. "Why gases condense into liquids" and "What is the connection between the volume, temperature, pressure and other elements of gases", 150 years ago, Western scientists were very interested in the above problems, and successive studies continued for nearly half a century.
Finally, a Dutch physics teacher perfectly answered these questions in his doctoral dissertation, which won the 1910 Nobel Prize in Physics, and the formula in the paper was named after him.
Self-taught to take the Ph.D
In February 1873, the spring in Leiden, the Netherlands, was cold, and the flowers on the street were ready to be released. In a laboratory at Harvard Business School in the east of the city, physics teacher Van Der Waals concentrates on experimenting with oxygen. When he turned oxygen into liquid oxygen through high pressure, the results calculated using the Clapelon equation of state of affairs were not the same as the results of experimental tests, and he could not help but wonder.
Official photo of Van Der Waals's Nobel Prize (Source: Physics Bimonthly)
The Clapelon equation of state is a thermodynamic equation summed up by Beaunova Paul Emile Clapelon, an academician of the French Academy of Sciences in 1837, which mainly describes the mathematical relationship between gas volume, pressure, temperature, etc. This equation consists of three aspects: the volume of the gas is inversely proportional to the pressure, proportional to the temperature, and proportional to the number of particles.
Within a few years, scientists discovered that the Clapelon equation of state had a drawback, which was that it did not apply the interchangeable description of gas and liquid at high pressures. In other words, this equation can only calculate the relationship between the elements of the gas under normal gas pressure.
There is an unwritten phenomenon in the scientific community: when old theories do not apply under general conditions, new theories become the focus of scientists' pursuit. Scientists have joined the study of the new theory, including Van Der Waals. Van der Waals's original name was Johannes Didric van der Valls.
His father was an ordinary carpenter in the city of Leiden and had ten children. As the eldest son, van der Waals took on the responsibility of the eldest brother very early and set an example for his younger siblings. In school, he is a bully, with good grades in all doors, and when he graduated from middle school at the age of 15, he became a primary school teacher and subsidized his family with his salary. Not content with mediocrity, van der Waals, who did not go to college, earned money to support his family while attending lectures on physics, mathematics and astronomy at Leiden University, a well-known local university. Within a few years of self-taught talent, his knowledge surpassed that of regular college students.
The first university in the Netherlands, Leiden University (Source: Study Abroad Network)
Opportunities are left to those who are prepared. In 1865, the Dutch government created Harvard Business School, which specialized in serving middle- and upper-class children, and openly recruited teachers.
Van der Waals passed the exams and became a physics teacher at the school. He cherished the hard-won opportunity to teach diligently and engage in physics research at the same time. If you want to make a difference in science, getting a Ph.D. is the key. Van der Waals was well aware of the success code at that time, and he applied for a Ph.D. in physics and a Ph.D. in mathematics from Leiden University to prepare for thesis defense.
He first prepared a physics paper and chose a "hard bone" as the theme of the paper, that is, to find out the real reason why the Clapelon equation of state fails at high pressure, and to come up with a new equation of state of matter. This is the question he had in the lab.
Doctoral thesis innovation law
Vandervat, who is intoxicated with the study of gas states, deals with microscopes, dosing instruments, etc. in addition to teaching. At the same time, he insisted on reading thermodynamic classics of the same era, and the works of Maxwell, Boltzmann, Gibbs and other big names helped him a lot. The days pass by day after day at busy work. Van der Waals's efforts were not in vain.
On 14 June 1873, his doctoral dissertation , " On the Continuity of Gaseous and Liquid " , was successfully defended at leiden University. He was among Europe's leading physicists. In this paper, he mentions two unprecedented theories: one is that the real reason why the Claperon equation of state fails at high pressure is that it does not consider the attraction between gas molecules; and the other is the innovative derivation of the equation of state that can be applied to high-pressure gases, which the article calls "van der Waals's equation".
Van der Waals equation, where a and b are constants (Source: Baidu)
Scientists in Europe and around the world are interested in both theories. After years of research, scientists have finally learned that whether it is a solid, liquid or a gas, there is an attraction between their molecules or atoms. They call this attraction "van der Waals force," which has a decisive effect on the melting point, boiling point, solubility and other physical properties of the substance.
Regarding van der Waals equations, in addition to european scientists have studied them, the Proceedings of the Royal Netherlands Academy of Sciences have published papers on van der Waals' equations.
These papers were also translated into other Chinese to enhance the exchange of science in the world. No wonder Maxwell predicted in the journal Nature: "There is no doubt that van der Waals' name will soon appear at the forefront of molecular science." ”
Keep up the good work
Through his doctoral dissertation defense, van der Waals became a well-known figure in the European scientific community. In the face of honor, he is not arrogant and impatient, and continues to climb to the peak of science. Later, he represented van der Waals' equations as functions and replaced the compounds in the equations with a or b, which was more computationally efficient. As a result, scientists have produced liquefied hydrogen and liquefied helium.
Later, van der Waals combined the equations he discovered with the second law of thermodynamics, using mathematical formulas or graphs to represent the various properties of thermal forces. Scientists started with Van der Waals' paper and came to a surprising conclusion: the gecko can crawl on smooth glass because the villus molecules of its toes and the glass molecules produce a powerful van der Waals force.
Molecules on the gecko's feet and molecules of objects produce van der Waals forces (Source: Sohu)
Van der Waals' contribution was first recognized by the Dutch government. In 1877 he was appointed the first professor of physics at the Stadthusse university of Amsterdam.
More than 10 years later, the Royal Netherlands Academy of Sciences hired him as secretary. Countries around the world have also given him enough honors: he has been awarded an honorary doctorate from the University of Cambridge in the United Kingdom, a corresponding member of the Royal Academy of Sciences in Berlin, and a foreign member of the National Academy of Sciences of the United States.
Outstanding contribution, honor, and thermal giant, after the 1909 Nobel Prize in Physics was awarded to scientists in the field of wireless, van der Wa was immediately nominated as a candidate for the new Physics Prize. Everything went according to the process, and van der Waals stood on the podium of the 1910 Nobel Prize in Physics.
From poor students to world-class masters, he used his personal experience to compose a song of praise for self-taught talent.
END
【References】
1. The book "One Hundred Years of the Nobel Prize in Physics", published by Shanghai Science Popularization Publishing House in 2002, is written by Guo Yiling and Shen Huijun.
2. The paper "The Great Epitome of Physics in the 20th Century", by Guo Yiling, Tsinghua University, Physical Research, No. 2, 2009.
3. "Scientific Analysis of Gecko Climbing Walls", by Zhao Xinghua, Bulletin of Physics, No. 10, 2014.
Tadpole stave original article/reprint indicates the source
Editor-in-charge/Heart & Paper