There are many different experiments which can give varying intelligence about the makeup of matter, in different ways and with different conclusions. In this instance I will be looking at the discovery of the electron, how our understanding of it has changed over the years, and measure how it has contributed to where we are today.
Joseph John Thomson (J. J. Thomson, 1856 - 1940) is widely recognized as the discoverer of the electron. Thomson was a Professor of Experimental Physics at Cambridge University, and Director of its Cavendish Laboratory, from 1884 until 1919. It is here where his most well-known, varied and comprehensive work, in the field of conduction of electricity within gases, was undertaken. In 1897 Thompson made an announcement stating that cathode rays were negatively charged particles which he referred to as 'corpuscles', and pronounced that they had a mass some 1,000 times less than a hydrogen atom. Thompson proposed that corpuscles were the items from which atoms were constructed, and concluded that cathode rays possessed a new state by merit of their ability to carry further than the ordinary gaseous state. This was proposed as a state in which all matter is derived from different sources, such as hydrogen or oxygen. This implied that the original discovery was different to the one Thompson now proposed, that the particles were a fundamental element of all matter.
Thompson’s experiment used a pair of plates as electrodes in a glass tube, between which a high voltage potential was applied. When the pressure of the gas in the tube became very low (less than 0.1 atmospheres), an electric discharge took place. This was referred to as vacuum discharge. When the gas pressure in the tube was further reduce...
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...ituation. We would lack an understanding of the anatomy of atoms, and how they are made up of a nucleus with surrounding electrons, and the influence they have on the world around us, and how it works. The importance of electrons would not be appreciated, nor their relevance to experiments on the theory of matter.
Works Cited
1) Anthony Carpi, Ph.D. "Atomic Theory I: The Early Days," Visionlearning Vol. CHE-1 (2), 2003.
2) J.J. Thomson (1897), Cathode rays, Philosophical Magazine, 44, 293 — The classic measurement of the electron mass and charge
3) Thomson, George Paget. (1964) J.J. Thomson: Discoverer of the Electron. Great Britain: Thomas Nelson & Sons, Ltd.
4) Navarro, Jaume, 2005, "Thomson on the Nature of Matter: Corpuscles and the Continuum," Centaurus 47(4): 259-82.
5) Nobel Lectures, Chemistry 1901-1921, Elsevier Publishing Company, Amsterdam, 1966
In 1895, Professor Wilhelm C. Roentgen, a German physicist, was working with a cathode ray tube, much like our fluorescent light bulb. The tube consisted of positive and negative electrodes encapsulated in a glass envelope. On November 8, 1895, Roentgen was conducting experiments in his lab on the effects of cathode rays. He evacuated all the air from the tube and passed a high electric voltage through it after filling it with a special gas. When he did this, the tube began to give off a fluorescent glow. Roentgen then shielded the tube with heavy black paper and discovered a green colored fluorescent light could be seen coming from a screen located a few feet away from the tube.
Physicist in the 1900 first started to consider the structure of atoms. The recent discovery of J. J. Thomson of the negatively charged electron implied that a neutral atom must also contain an opposite positive charge. In 1903 Thomson had suggested that the atom was a sphere of uniform positive electrification , with electrons scattered across it like plum in an pudding. (Later known as the Plum Pudding Model)
The cathode ray tube was invented in 1875 by the name of Sir Williams Crooke. Yet he wasn’t the one to make the big discovery. In 1897, a man by the name of J.J. Thompson conducted a series of experiments to prove the existence of subatomic particles. He wasn’t 100% correct with all of his claims he made but broke the theory John Dalton stated that the smallest form matter could be broken down to was an atom. Having shown the world that there was smaller than an atom, it later caused others to question and dive even deeper.
Although the atomic theory was developed in increments, George Johnston Stoney is most famous for contributing the term electron: fundamental unit quantity of electricity. Stoney would develop the concept fourteen years before he coined the term electron. He also made contributions to the theory of gasses, cosmic physics, and estimated the number of molecules in a cubic millimeter of gas.
physics. The work of Ernest Rutherford, H. G. J. Moseley, and Niels Bohr on atomic
Discovered that certain chemicals glowed when exposed to cathode rays. These chemicals were special because they weren’t deflected by the magnetic field produced in the cathode ray tube (which was built by Sir William Crookes in 1870).
One thunderous afternoon on June 1752, Benjamin Franklin conducted what is known today as the “Kite Experiment”. He wanted to prove that if one object was electrical, the energy from that object could be transferred to another object, therefore being classified as electricity and lightning. With his son William, Ben took a string and attached the kite to it, then he attached an iron key to the kite. Next, they tied a thin metal wire from the key and put the wire inside a Leyden jar which stored all the electrical charge. His experiment profitably showed that his accusations were correct. Many other scientist tried the same experiment and were electrocuted, but Ben Franklin was the lucky one. He changed the world of science.
In the 1920s the new quantum and relativity theories were engaging the attentions of science. That mass was equivalent to energy and that matter could be both wavelike and corpuscular carried implications seen only dimly at that time. Oppenheimer's early research was devoted in particular to energy processes of subatomic particles, including electrons, positrons, and cosmic rays. Since quantum theory had been proposed only a few years before, the university post provided him an excellent opportunity to devote his entire career to the exploration and development of its full significance. In addition, he trained a whole generation of U.S. physicists, who were greatly affected by his qualities of leadership and intellectual independence.
They new the structure and particle makeup of atoms, as well as how they behaved. During the 1930Õs it became apparent that there was a immense amount of energy that would be released atoms of Gioielli 2certain elements were split, or taken apart. Scientists began to realize that if harnessed, this energy could be something of a magnitude not before seen to human eyes. They also saw that this energy could possibly be harnessed into a weapon of amazing power. And with the adven...
Fowler, Michael. “Modern Physics.” Lecture. Mass and Energy. 1 Mar. 2008. Web. 13 Oct. 2013.
John Dalton Around September 2, 1766, John Dalton was born. He was born in Eaglesfield, England. Dalton was most known for the development of the modern atomic theory. Dalton was taught at his early ages of learning by his father and a Quaker teacher whom in 1778 Dalton would replace him after he retired. He quit that job and left his village to work with his cousin in Kendal, but he stayed as a teacher.
The next big step in the discovery of the atom was the scientific test that proved the existence of the atom. After the discovery of the atom we had the discovery of subatomic particles. With the discovery of the subatomic particles came the research, which came from experiments that were made to find out more about the subatomic particles. This research is how we uncovered that most of the weight of an atom is from its nucleus. With the gold foil experiment, tested by Ernest Rutherford, he discovered the existence of the positively charged nucleus. He proved this when the experiment was happening, a small fraction of the photons th...
Throughout Thomson’s life he made many contributions to science. These include discoveries in thermodynamics and the age of the Earth, as well as innovating the Transatlantic Cable and inventing a tide meter. After exploring thermodynamics for some time, he developed the second law of thermodynamics. This law states that there cannot be a reaction that is completely efficient; a portion of the energy is lost to heat in each reaction. It also says that heat flows to areas that...
Scientists from earlier times helped influence the discoveries that lead to the development of atomic energy. In the late 1800’s, Dalton created the Atomic Theory which explains atoms, elements and compounds (Henderson 1). This was important to the study of and understanding of atoms to future scientists. The Atomic Theory was a list of scientific laws regarding atoms and their potential abilities. Roentagen, used Dalton’s findings and discovered x-rays which could pass through solid objects (Henderson 1). Although he did not discover radiation from the x-rays, he did help lay the foundations for electromagnetic waves. Shortly after Roentagen’s findings, J.J. Thompson discovered the electron which was responsible for defining the atom’s characteristics (Henderson 2). The electron helped scientists uncover why an atom responds to reactions the way it does and how it received its “personality”. Dalton’s, Roentagen’s and Thompson’s findings helped guide other scientists to discovering the uses of atomic energy and reactions. Such applications were discovered in the early 1900’s by using Einstein’s equation, which stated that if a chain reaction occurred, cheap, reliable energy could b...
According to the de Broglie relation and Bragg's law, a beam of 54 eV had a wavelength of 0.167 nm. The experimental outcome was 0.165 nm via the grating equation, which closely matched the predictions. Davisson and Germer's accidental discovery of the diffraction of electrons was the first direct evidence confirming de Broglie's hypothesis that particles can have wave properties as well.