Joseph John Thomson Essay

The history of the discovery of the electron was long and difficult. Many experimenters approached it, even more theorists thought about it. However, the British physicist Joseph John Thomson made the maximum contribution to the experimental and theoretical part. Therefore, it makes sense to explore not only about his work related to the electron, but also to touch on his biography. This wonderful English scientist regarded as one of the most prominent researchers who were able to think exclusively constructively. In such a way, the main aims of the assignment are to speak about the man who made the most for understanding the nature of the electron, to explore the life and achievements of Joseph John Thomson.

Joseph John Thomson (1856–1940) was born on December 18, 1856 in England, near Manchester, in Cheetham Hill. His father, a bookseller, died when Joseph John was sixteen years old. He wanted his son to be an engineer. Two years before his father died, in 1870, Joseph John enrolled at Owens College, founded by the Manchester merchant in 1846, which later became the University of Manchester. At that time, such prominent scholars as Reynolds, Osborne and Roscoe headed the college. Thomson’s math teacher, who paid attention to his extraordinary abilities, advised the young man to continue studying mathematics in the place, where the famous geometer Isaac Newton had studied and taught in the past. In 1876, Joseph John entered Trinity College at the Cambridge University (Thomson, 1964). In 1880, he received a bachelor’s degree, and in a few years later, he became a Master of Mathematics, and in both cases with honors.

To continue, it is important to note that in 1884, at the age of 27, Thomson was appointed to become a Professor of Experimental Physics and the Director of the Cavendish Laboratory. He was greatly appreciated as a mathematician-physicist. He actively applied the Maxwell theory of electromagnetism, which was taken into account during his appointment to this position. Thomson’s works were devoted to the study of the passage of electric current through rarefied gases, cathode and X-rays, as well as atomic physics also occupied a great place in Thomson’s scientific activities.

Thomson was most famous for his work related to the discovery of an electron. In 1897, investigating the deviation of cathode rays in magnetic and electric fields, Thomson discovered that they represent a stream of negatively charged particles. He measured the ratio of the charge of particles to mass and showed that they were in 1837 times lighter than a hydrogen atom (Laidler, 1988). In 1899, he discovered electrons in a photocurrent, observed the effect of thermionic emission. He studied the characteristics of the electric discharge in gases and explained the continuous X ray spectrum.

Exploring the work and the main achievements of Joseph John Thomson, it is important to pay a special attention to the way, in which he discovered the electron. In his experiment, Thomson used an improved cathode ray tube. Electric coils that created (according to Ampere’s law) a magnetic field inside the tube supplemented the design of the tube. He also used a set of parallel electric capacitor plates, which also created an electric field inside the tube (Robotti, 1997). This made it possible to investigate the behavior of cathode rays under the influence of both magnetic and electric fields. In such a way, using a tube of new design, Thomson consistently showed that: 1) the cathode rays are deflected in a magnetic field in the absence of an electric one; 2) the cathode rays are deflected in an electric field in the absence of a magnetic field; and 3) with the simultaneous action of electric and magnetic fields of balanced intensity, oriented in directions causing separately deviations in opposite directions, the cathode rays propagate in a straight line, that is, the action of the two fields is mutually balanced.

It means that Thomson found out that the ratio between electric and magnetic fields, in which their action was balanced, depended on the speed with which the particles move. After a series of measurements, Thomson was able to determine the speed of movement of the cathode rays. It turned out that they move much slower than the speed of light, which means that the cathode rays can only be particles, since any electromagnetic radiation, including the light itself, propagates at the speed of light (Falconer, 1998). Thomson gave the title to these unknown particles and called them “corpuscles”, but soon they became known as “electrons”.

In addition, it is possible to state that Thomson was also one of the founders of the electronic theory of metals (1900). He obtained a formula for the effective cross section for the scattering of electromagnetic waves by free electrons (the Thomson formula). In 1903, he built one of the first models of the atom, assuming that the atom is a positively charged sphere with electrons interspersed into it. In 1904, Thomson proposed the idea that electrons form various configurations in the atom that determine the periodicity of chemical elements; thus, he tried to establish a connection between the electronic structure of the atom and its chemical properties.

Exploring some personal characteristics of this person, it is good to state that J.J. Thomson was not a brilliant lecturer in the direct sense of the word, but his lectures impressed the audience with the crystal clarity with which he explained the material, as well as the simplicity and beauty of the lecture demonstrations (Davis and Falconer, 1997). Moreover, Thomson could say something interesting and even new about almost any subject. He was a good storyteller and a good listener; he knew how to draw the word out of the shyest member of the company. When J.J. Thomson paced around the room and spoke energetically about something, the image of a lion locked in a cage came to mind. Thus, Thomson’s autobiography includes many examples showing that he was a great narrator. In his memoirs, he wrote funny stories in which he, his friends and colleagues got into his long life.

In conclusion, we have explored the life and the main achievements of Joseph John Thomson and have proved that he was a prominent person, who made a lot for the development of modern physics. The results of his researches have played an important role in the further discovery of the photoelectric effect and thermoelectric emission. Joseph John Thomson established the nature of positive ions and gave an explanation to the continuous X ray spectrum. He developed a parabolic method for measuring the ratio of the electric charge of an elementary particle to its mass, thereby opening the way for a large-scale study of isotopes. For his scientific work, the scientist won many valuable awards (Royal Medal in 1894, Hughes Medal in 1902, Copley Medal in 1914, Albert Medal in 1915, Franklin Medal in 1922, and Faraday Medal in 1925, as well as he got Smiths Prize in 1880 and Adams Prize in 1884. He also was the winner of the Nobel Prize in 1906. Thus, for achievements in the field of scientific activity and the greatest contribution to the development of many areas of science Joseph John Thomson was buried in Westminster Abbey in London.

Works Cited

Davis, E. and Falconer, I. J.J. Thomson and the Discovery of the Electron. Taylor & Francis, 1997.

Falconer, I. “J.J. Thomson’s Work on Positive Rays, 1906–1914.” Historical Studies in the Physical and Biological Sciences, vol. 18, no. 2, 1998, pp. 265-310.

Laidler, K. To Light Such a Candle: Chapters in the History of Science and Technology. Oxford University Press, 1998.

Robotti, N. “The discovery of the electron: I.” European Journal of Physics, vol. 18, no. 3, 1997. 

Thomson, G. P. J.J. Thomson: Discoverer of the Electron. Great Britain: Thomas Nelson & Sons, Ltd, 1964.

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[Accessed: April 1, 2020]

"The terms offer and acceptance." freeessays.club, 17 May 2016

[Accessed: April 1, 2020]

"The terms offer and acceptance." freeessays.club, 17 May 2016

[Accessed: April 1, 2020]