Physics Basics and History by Assignment Experts

Although apparently, physics consists in searching or finding a mathematization of observable reality, it is not so. What happens is that mathematics is the language in which what is said in physics can be expressed more precisely.

From an applied point of view, the field of physics is much broader, since it is used, for example, in the explanation of the emergence of emerging properties, more typical of other sciences such as Sociology and Biology. This means that physics and its methods can be applied and used in other fields of science and used for any type of scientific research.

Physics is one of the Natural Sciences that has contributed most to the development and well-being of man because thanks to his study and research it has been possible to find an explanation to the different phenomena of nature, which are presented daily in our daily life. As for example, something so common for some people as rain, among many others.

                                                                                            


Brief Definition of Physics

Physics is the science dedicated to the study of the forces that occur in nature, in the broadest sense of the search for knowledge. Physics is also, a natural science that studies the properties of space, time, the matter, the energy and its interactions.

History of Physics

From the most remote antiquity, people have tried to understand the nature and the phenomena that are observed in it: the passing of the seasons, the movement of the bodies and the stars, the climatic phenomena, the properties of the materials, etc. The first explanations appeared in Antiquity and were based on purely philosophical considerations, without being verified experimentally. Some false interpretations, such as that made by Ptolemy in his famous "Almagest" - "Earth is at the centre of the Universe and around it the stars rotate" - lasted for centuries. Ideas that the Catholic Church defended for their interests.

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                                                                    Covers of two of the most important works of the Scientific Revolution:
                                                           The Sidereus Nuncius of Galileo Galilei and the Principia Mathematica of Isaac Newton.

The Twentieth Century: The Second Revolution of Physics

The twentieth century was marked by the development of physics as a science capable of promoting technological development. At the beginning of this century physicists considered having a quasi-complete vision of nature. However, two profound conceptual revolutions soon followed: The development of the theory of relativity and the beginning of quantum mechanics.

                                                                                       
                                                                         Albert Einstein is often considered as the
                                                                     most popular icon of science in the twentieth century.

In 1905 Albert Einstein formulated the theory of spatial relativity, in which space and time are unified into a single entity, space-time. Relativity formulates different equations for the transformation of movements when observed from different inertial reference systems to those given by classical mechanics. Both theories coincide at small speeds in relation to the speed of light. In 1915 he extended the spatial theory of relativity to explain gravity, formulating the general theory of relativity, which replaces Newton's law of gravitation. In 1911 Ernest Rutherford deduced the existence of an atomic nucleus positively charged from experiences of dispersion of particles. The positively charged components of this nucleus were called protons. The neutrons, which are also part of the nucleus but have no electric charge, were discovered by James Chadwick in 1932.


                                                                            

                                                                                       Bohr's atomic model,
                                                                               one of the first bases of quantum mechanics.

In the early years of the twentieth century Max Planck, Albert Einstein, Niels Bohr and others developed quantum theory in order to explain anomalous experimental results about the radiation of bodies. In this theory, the possible levels of energy become discrete. In 1925 Werner Heisenberg and in 1926 Erwin Schrödinger and Paul Dirac formulated quantum mechanics, in which they explain the preceding quantum theories. In quantum mechanics, the results of physical measurements are probabilistic; Quantum theory describes the calculation of these probabilities.

Quantum mechanics provided the theoretical tools for the physics of condensed matter, which studies the behaviour of solids and liquids, including phenomena such as crystalline structure, semi-conductivity and superconductivity. Among the pioneers of the physics of condensed matter is Felix Bloch, who developed a mechano-quantum description of the behaviour of electrons in crystalline structures (1928).

The quantum field theory was formulated to extend quantum mechanics in a manner consistent with the special theory of relativity. It reached its modern form at the end of the 1940s thanks to the work of Richard Feynman, Julian Schwinger, Tomonaga and Freeman Dyson. They formulated the theory of quantum electrodynamics, in which the electromagnetic interaction is described.

The quantum field theory provided the basis for the development of particle physics, which studies fundamental forces and elementary particles. In 1954 Yang Chen Ning and Robert Mills developed the bases of the standard model. This model was completed in the 1970s and it describes almost all the elementary particles observed.

                                                   The equivalence between mass and energy are given in Einstein’s theory of relativity,

                                                                                                E = mc2,
                                        indicates that the mass carries a certain amount of energy although is at rest, a concept absent in classical mechanics.

DIVISION OF PHYSICS

Physics is divided for study in two major groups, classical physics and modern physics. Classical physics does not take into account the relativistic effects, discovered by Einstein, nor the quantum effects, considering Plank's null constant. Modern physics does take these factors into account, giving rise to relativistic physics and quantum physics.

At the end of the 19th century, the branch called Modern Physics emerged in Physics, after scientists discovered that in nature there are phenomena that cannot be explained or verified by the laws or procedures established by Classical Physics, such as Newton's laws for mechanical phenomena or Maxwell's for electromagnetic phenomena; these phenomena arise when very small particles, at the molecular or atomic level and very large particles at the interstellar level, move at speeds very close to the speed of light, greater than 0.99C. When these phenomena were analyzed, with classical mathematical models, they did not coincide with the measurements made.

INTRODUCTION TO MODERN PHYSICS

The phenomena that can be cited, which gave rise to this branch of physics are:

The black body radiation - Max Plank to explain this phenomenon proposed that this energy radiation is not continuous, but that the energy emitted by a hot body is discrete, that is, the emission is carried out in the form of packages, called "quanta of energy".

In the photoelectric effect, it is shown that a wave of light with a certain amount of energy, depending on its frequency or colour, can energize electrons located inside a photosensitive material and detach them from it; instead of light of another colour does not affect the same eviction.

The considerable increase in mass of a particle when its speed is greater than0.99C, where C is the speed of light, equal to 3x 108 m/s.

The radioactivity and the enormous release of energy as heat during the process of nuclear fission and fusion. Processes that gave rise to the nuclear age that we began to live.

The coherent light, a product of energy radiation when an electron jumps from a quantified energy level to its level of fundamental energy, which gave way to the development of the laser beam, which so many applications currently have in a number of human activities.

The wave behaviour of electrons in motion produces diffraction patterns when projected on a simple nickel crystal card.

The Compton Effect, in which waves like "X" rays behave like particles with an energy and a quantity of movement dependent on frequency and that can deflect, after a collision, the path of charged particles in motion.

The light of an electric spark in a gaseous medium does not produce a continuous spectrum of frequencies when passing it through a crystal prism or a diffraction network, which leads us to assume that the gases have a unique characteristic spectrum (absorption spectrum).

The shape of the atomic structure of matter, etc.  The study of these phenomena and others has led engineers to develop new devices such as laser beam, microwave ovens, electron microscopy, nuclear power controllers, nuclear power plants, etc.

The theories of relativity were named by Albert Einstein: the special and the general; and they were initially used to explain physical phenomena related to particles that move at speeds close to the speed of light since Newton's laws applied in the explanation of these phenomena presented calculation errors with the measurements made. Albert Einstein proposed the present errors were due to the conceptualization of the reference systems with which the phenomenon was observed.

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