The Contributions by Niels Bohr , Danish physicist, are considered among the most important of the twentieth century, when looking back and reflect on their contributions to the world of chemistry, physics and science.
Niels Bohr was awarded the Nobel Prize in Physics in 1922 for his research on the structure of atoms and their radiation levels.
Raised and educated in European lands, in the most prestigious English universities, Niels Bohr was also a renowned researcher and curious philosopher.
He worked with other renowned scientists and Nobel Prize winners, such as J.J. Thompson and Ernest Rutherford, who urged him to continue his research in the atomic area.
Bohr's interest in atomic structure led him to move between universities until he found one that would give him the space to develop his research under his own terms.
Niels Bohr started from the discoveries made by Rutherford to continue developing them until he could print his own imprint.
Bohr came to have a family of more than six children; He became tutor to other scientific eminences such as Werner Heisenberg; Was president of the Royal Danish Academy of Sciences, as well as member of other scientific academies around the world.
Main contributions of Niels Bohr
Bohr and Albert Einstein
Model and structure of the atom
The atomic model discovered by Niels Bohr is considered one of his greatest contributions to the world of physics and the sciences in general.
It was the first to exhibit the atom as a positively charged nucleus and surrounded by orbiting electrons.
Bohr was able to discover the mechanism of internal functioning of an atom: the electrons are able to orbit independently around the nucleus.
The number of electrons present in the outer orbit of the nucleus determines the properties of the physical element.
To obtain this atomic model, Bohr applied Max Planck's quantum theory to the atomic model developed by Rutherford, resulting in the model that earned him the Nobel Prize. Bohr introduced the atomic structure as a small solar system.
Quantum concepts at the atomic level
What led to the atomic model of Bohr to be considered revolutionary, was the method that it used to obtain it: the application of theories of quantum physics and its interrelation with the atomic phenomena.
With these applications, Bohr was able to determine the movements of the electrons around the atomic nucleus, as well as the changes in its properties.
Likewise, through these concepts, he was able to obtain a notion of how matter is capable of absorbing and emitting light from its most imperceptible internal structures.
Discovery of the Bohr-van Leeuwen Theorem
Theorem Bohr-van Leeuwen is a theorem applied to the area of mechanics. Worked first by Bohr in 1911 and then supplemented by van Leeuwen, the application of this theorem achieved to differentiate the reaches of classical physics versus quantum physics.
The theorem states that the magnetization resulting from the application of classical mechanics and statistical mechanics will always be zero.
Bohr and van Leeuwen managed to glimpse certain concepts that could only be developed through quantum physics.
Today the theorem of both scientists is successfully applied in areas such as plasmas physics, electromechanics and electrical engineering.
Principle of complementarity
Within the quantum mechanics, the principle of complementarity formulated by Bohr, which represents a theoretical and resultant approach at the same time, maintains that the objects subjected to quantum processes have complementary attributions that can not be observed or means simultaneously.
This principle of complementarity arises from another postulate developed by Bohr: the Copenhagen interpretation; Fundamental for the investigation of quantum mechanics.
Interpretation of Copenhagen
With the help of scientists Max Born and Werner Heisenberg, Niels Bohr developed this interpretation of quantum mechanics, which made it possible to elucidate some of the elements that make mechanical processes possible, as well as their differences. Formulated in 1927, it is considered a traditional interpretation.
According to the Copenhagen interpretation, physical systems do not have definite properties before being subjected to measurements, and quantum mechanics is only able to predict the probabilities by which the measurements made will yield certain results.
Structure of the periodic table
From his interpretation of the atomic model, Bohr was able to structure in a more detailed way the periodic table of elements that existed at that time.
He was able to affirm that the chemical properties and the binding capacity of an element are closely related to its charge of valences.
Bohr's works applied to the periodic table gave rise to the development of a new field of chemistry: quantum chemistry.
Similarly, the element known as Boro (Bohrium, Bh), receives its name in homage of Niels Bohr.
Nuclear Reactions
Through a proposed model, Bohr was able to propose and establish the mechanisms of nuclear reactions from a two-step process.
By bombarding low-energy particles, a new low-stability core is formed that eventually emits gamma rays, while its integrity declines.
This discovery of Bohr was considered key in the scientific area for a long time, until it was worked and improved, years later, by one of its children, Aage Bohr.
Explanation of nuclear fission
Nuclear fission is a nuclear reaction process whereby the atomic nucleus begins to divide into smaller parts.
This process is capable of producing large quantities of protons and photons, releasing energy at the same time and in a constant way.
Niels Bohr developed a model that allowed to explain the nuclear fission process of some elements. This model consisted of observing a drop of liquid that would represent the structure of the nucleus.
In the same way that the integral structure of a drop can be separated into two similar parts, Bohr was able to demonstrate that the same can happen with an atomic nucleus, being able to generate new processes of formation or deterioration at atomic level.
References
- Bohr, N. (1955). Man and physical science. Theoria: An International Journal for Theory, History and Foundations of Science , 3-8.
- Lozada, R. S. (2008). Niels Bohr. University Act , 36-39.
- Nobel Media AB. (2014). Niels Bohr - Facts . Obtained from Nobelprize.org: nobelprize.org
- Savoie, B. (2014). A rigorous proof of the Bohr-van Leeuwen theorem in the semiclassical limit. RMP , fifty.
- The Editors of Encyclopædia Britannica. (November 17, 2016). Compound-nucleus model . Retrieved from"Encyclopedia Britannica": britannica.com.