The discovery of the atom’s complex structure is the most crucial stage in the formation of modern physics. In creating a quantitative theory of the design of the atom, which made it possible to explain atomic systems, new ideas were formed about the properties of microparticles, which quantum mechanics describes. This paper aims to investigate the development of atomic theory from ancient Greeks to modern physics.
The concept of atoms as indivisible minute particles of substances arose in ancient times. Ancient Greek philosophers suggested that atoms differ in their shape depending on the type. For example, iron atoms were thought to be hooks that clung to each other, explaining why iron was solid at room temperature. Water atoms were smooth and slippery, so the water was liquid at room temperature (Haas 1). And although we now know that this is not so, their ideas were laid down based on future atomic models.
By the 18th Century, the atomistic approach is gaining popularity. By this time, such scientists as Lavoisier, Lomonosov, and Dalton proved the reality of the existence of atoms. Dalton relied on the ideas of the ancient Greeks in describing atoms as tiny, solid, indivisible spheres. Like Greek philosophers, Dalton’s atoms of one element are identical to each other. The last point is still essentially correct, except for the isotopes of various factors, which differ in the number of neutrons (Peterman and Cordes). Dalton also suggested how atoms combined to form compounds and provided the first set of chemical symbols for known elements.
In the late 1800s, Joseph John Thomson discovered that the atom was not as indivisible as previously claimed. He experimented with cathode rays produced in a discharge tube and found that positively charged metal plates attract cathode rays, whereas negatively charged ones repel. Thus, Thomson concluded that the rays must be negatively charged. By studying the particles in rays, he revealed that they were two thousand times lighter than hydrogen. By changing the metal of the cathode, Thomson demonstrated that these particles were present in many types of atoms (Helrich). Thus, he discovered the electron (although he referred to it as a “corpuscle”) and showed that atoms are not indivisible.
However, Ernest Rutherford introduced a new understanding of the atomic model. Rutherford devised an experiment that helped investigate atomic structure. By conducting this experiment, Rutherford hoped to confirm Thomson’s model. Nonetheless, Rutherford observed that the alpha particles when going through the foil almost without deflection. Nevertheless, a minimal number of particles deviated from the intended path while deviating at a substantial angle. The only answer was that the positive charge did not spread throughout the entire atom but was localized in a small, dense center – the nucleus. According to this, most of the rest of the atom was just empty space. It meant the need to rethink the atomic model (Haas 97). He proposed a model in which electrons revolve around a positively charged nucleus. He did not explain what keeps the electrons orbiting the nucleus instead of just falling onto the nucleus.
Niels Bohr presented the new model, setting about solving problems related to Rutherford’s model. In this way, Bohr’s model, which was based on quantum theory to analyze the arrangement of electrons, demonstrated the stable level of electron shells, which is basically energy. (Haas 25). In other words, it can be stated that electrons can only be found at these energy levels. Electrons can move between these energy levels (referred to by Bohr as “stationary states”) but are subject to the absorption or emission of energy. Bohr’s model works well for hydrogen atoms but cannot apply to heavier elements. Also, it does not correlate with the Heisenberg Uncertainty Principle, which states that we cannot know exactly when and where an electron will be passing through at a particular time. Nevertheless, Bohr’s atom model is the most widespread and known, which is associated with the convenience of explaining the chemical bond and reactivity of some groups of elements at the initial stage of training.
In 1926, Schrödinger suggested that electrons and other elementary particles behave like waves on the ocean surface. Over time, the wave’s peak (corresponding to the place where the electron is most likely to be located) shifts in space according to the equation describing this wave (Helrich). That is, what we traditionally considered a particle in the quantum world behaves much like a wave.
In 1932, after Schrödinger, the English physicist James Chadwick (Rutherford’s student) revealed the neutron’s existence, which completed our image of subatomic particles of the atom (Ecker). Moreover, physicists empirically proved that neutrons and protons that constitute the nucleus themselves split into quarks. In general, the atomic model gives us a great example of how scientific models can evolve and shows how new data can lead to new models.
Impact of The Development And The Application of New Technologies in the 19th Century
The 19th Century is remarkable with its bright discoveries that affected the development and implementation of technology. During this time, such technologies as fax, telephone, electric trains, and many others were not only introduced to the public but also found an active application in the day-to-day life of people. Implementation of these new technologies impacted the vision of life and helped people reorganize the way of their lives in a more effective and easier way. Later, these technologies were improved, modified, and adapted to have better performance, but the base for their development started in the 19th Century.
Although we do not use fax today, the first prototype of the popular 2000s device appeared in the 19th Century. In 1843, Alexander Bane received a British patent for a facsimile machine. Working on an experimental device between 1843 and 1846, he was able to synchronize the movement of the pendulums of two clocks, located about 70 kilometers from each other, and using the received signal, scan the image line by line. Furthermore, in 1855, the Italian inventor Giovanni Caselli presented a similar device, which he called the Pantelegraph. The device was used on the communication lines Moscow-Petersburg (1866-68), Paris-Marseille and Paris-Lyon.
Another important device that we cannot imagine our household without is a refrigerator. In general, the refrigerator was invented in 1834, and people were able to store their food by buying ice for the device. Usually, the ice-breaker came two times a week to refill the refrigerators of the townspeople with cooling material. But already in 1850, physician John Gorey demonstrated the process of producing artificial ice in the device itself using the compression cycle technology.
Cement was first patented in 1824, and already in the 1880s, it was used for commercial and individual purposes in many countries around the world. To be more precise, it was Portland cement, which Joseph Aspdin obtained during the experiments. The invention of cement affected the construction industry and maintained further development of the industry, which shaped the landscape and structure of our cities.
In 1876, Alexander Graham Bell became the first to receive a US patent for a device that clearly reproduced the human voice. Subsequently, the device was developed in the hands of many other inventors. However, Bell’s invention’s effect on people’s lives was so immersive that it entirely changed the conventional way of communications (Pestrikov and Yermolov). The telephone became the first device in world history that allowed people to communicate over a long distance.
Also, in the second half of the 19th Century, another significant breakthrough changed the transportation industry. Werner von Siemens was the first one who introduced the first electric passenger train that was launched in Berlin in 1879, and it was called the “electric locomotive.”At that time, the invention became a sensation among the general public. This train had three carriages and a locomotive and gained a speed of 7 km/h due to a sequential winding engine (Subbiah and Nandivada). And in 1881, on the outskirts of Berlin, the first electric tramway passed, which moved at a speed of 30 km/h and transported more than 12 thousand passengers in 3 months.
Today it is difficult for us to imagine cleaning without a vacuum cleaner in a carpeted house. Not everyone knows that the first “helpers” appeared in the second half of the 19th Century. The patent was obtained in 1860 by the American Daniel Hess. He called his device a “carpet sweeper” (sweeping machine) and equipped it with a rotating brush (Robin). In 1889, a patent was obtained for a gasoline vacuum cleaner with a motor. Although the first electric analog was developed only at the beginning of the 20th Century, already in the 19th Century, these “helpers” became popular, and more and more households started using vacuum cleaners.
Joel Houghton patented the hand-operated dishwasher in 1850, but it was unreliable and not widely adopted. Almost 40 years later, in 1887, the first dishwasher that was suitable for practical use was invented by Josephine Cochrane. It comes with no surprise: indeed, who understands better what difficulties homemakers sometimes face if not a woman? Later in the 20th Century, it became electric, thus, allowing its usage at home.
Works Cited
Ecker, Gerhard. “James Chadwick: ahead of his time.” arXiv preprint arXiv:2007.06926 (2020).
Haas, Arthur. Atomic Theory: An Elementary Exposition. Walter de Gruyter GmbH & Co KG, 2020.
Helrich, Carl S. “The Atomic Theory.” History of Physics, 2021, pp. 1–40. Crossref, Web.
Peterman, Keith, and Matthew Cordes. “England: John Dalton and the Atomic Theory.” Contextualizing Climate Change: Linking Science and Culture. American Chemical Society, 2021. pp. 37-47.
Pestrikov, Victor M., and Pavel P. Yermolov. “The Struggle for the Range of Telephone Communication before the Invention of the Audion Lee de Forest.” ITM Web of Conferences, edited by P. Yermolov, vol. 30, 2019, p. 16002. Crossref, Web.
Subbiah, Vignesh Arumugam, and Yashasvi Nandivada. Advanced Control of Future Electric Propulsion Systems for Passenger Vehicles. MS thesis. 2018.
Robin, Roy. “A Story of Innovation: The Cyclone Vacuum Cleaner Invented by James Dyson.” Creative Academic Magazine, 2016, pp. 98–99.