History of physics from its origin to the present day

The history of physics dates back to Antiquity, where philosophers of classical Greece dedicated themselves to the study of the workings of the universe. Many started from observation as the tool that could lead them to understand the laws that govern the world. 

The movements of the Earth, the stars and the attempt to discover the origin of matter were several of the main points of research at the time. Furthermore, many of these reasonings served for the development of mechanics. 

Philosophers like Leucippus and Democritus proposed that matter was composed of atoms, a smaller, indivisible particle. In turn, Aristarchus of Samos was the first to discern that the Earth revolved around the Sun, making the first heliocentric model of the solar system, an astronomical plan that placed the Sun at the center, and not on Earth, as previously thought. was located.

Aristotle argued the importance of the four elements – air, earth, water and fire – in the process of formation of matter. He also stated that everything that moves is powered by an internal or external motor.

Other relevant figures, such as Archimedes of Syracuse, in the third century, made contributions to the study of mechanics, developing the bases for hydrostatics and statics.

He was also able to create a pulley system to reduce the effort when lifting weights. Hipparchus of Nicea was able to create a map of the movement of stars through geometry, which allowed us to detect astronomical events such as eclipses. 

Discoveries of the Islamic World

Many of the ancient studies were translated into Arabic at the time of the fall of the Roman Empire. Much of the Greek legacy was recovered by the Islamic world, allowing certain developments to take place in this community as well. Some of them include:

-Omar Khayyám (1048-1131), who calculated the length of a solar year and proposed a model calendar 500 years before the current Gregorian calendar.

-Avempace (1085-1138), one of the main forerunners of Newton’s third law, proposed that for every force employed there is a reaction force. He was also interested in speed and was an excellent commentator on Aristotelian works.

-Nasir al-Din al-Tusi (1201-1274), described in his work the circular motion of the planets in their orbits. 

Middle Ages

All the knowledge that could be inherited from the period before the Middle Ages was taken firsthand by church members. Academic scope was limited to copying church manuscripts. However, later on, there would be a conflict due to conflicts of faith.

The Christians’ dilemma regarding the translation and acceptance of texts of “pagan” origin from the Islamic world caused some aversion until the arrival of Thomas Aquinas, who managed to integrate Aristotelian knowledge and much of Greek philosophy into Christianity. . 

The Renaissance and the Scientific Revolution

The clamor for knowledge of the ancients continued throughout the Renaissance, but closely linked to religion, an aspect that had several consequences in terms of new discoveries. Anything that opposed Aristotelian thought or the church could be condemned.

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Such was the case for Nicholas Copernicus in the 16th century, when he claimed that the Earth and other planets revolved around the sun. This was immediately marked as heresy. According to Christian beliefs, the Earth was stationary and was at the center of the universe. 

Copernicus’ work would be published shortly before his death in 1543, based on the heliocentric model of the solar system developed by Aristarchus of Samos. The idea of ​​the Earth’s movement managed to be so revolutionary that it would give rise to the development of scientific thought in the coming centuries.

Galileo Galilei is also one of those who opposed the rigid academy imposed by the church. In this way, and taking as reference the works of Copernicus, after building his own telescope, he managed to discover new elements in the solar system. The mountainous surface of the Moon, the moons of Jupiter and the phases of Venus.

Galileo’s appreciation of Copernicus’ studies and his new discoveries led the Inquisition to sentence him to house arrest at the age of 68. However, he continued his work at home and entered the history of the greatest representatives in relation to the development of modern physics.

the scientific method

Rene Descartes

René Descartes is one of the main characters that marks the beginning of the scientific method in the 17th century. It is known for the development of reductionism, a method of study that consists in decomposing a problem into its various parts in order to analyze each one independently and, thus, understand the phenomenon or problem in its entirety.

Descartes claimed that the only way to understand the principles of nature was through reason and mathematical analysis. 

mechanics

Another of the great fundamental steps for the development of physics is the study of mechanics. Isaac Newton is one of the most influential in this field. 

His theory of gravitation in his publication Mathematical Principles of Natural Philosophy in 1687 explains how mass is attracted to another mass by a force inversely proportional to the square of the distance between them. Force known as “gravity”, present throughout the universe. 

Currently, Newton’s three laws are the most recognized contributions:

The first states that a body cannot change its movement unless another body acts.

The second, known as the “fundamental law”, states that the net force applied to a body is proportional to the acceleration that the body acquires.

The third law tells us the principle of action and reaction, stating that “if a body A exerts an action on another body B, it performs another action on A and in the opposite direction on B.”

heat studies

After inventions such as the steam engine by Thomas Newcomen (1663-1729), physics studies began to focus on heat. Heat came to be related to the workforce, through mechanisms such as water wheels. 

Later, American inventor Benjamin Thompson, known as Earl Rumford, noted the relationship between work and heat, noting how the surface of a cannon would heat up when it was drilled at the time of construction.

Later, British physicist James Prescott Joule (1818-1889) managed to establish a mathematical equivalence between work and heat. Also, find out what is known as Joule’s law, which relates the heat generated by the current through a conductor, the resistance of the conductor, the current itself, and the emission time. 

This discovery allows us to start laying the foundations for the laws of thermodynamics, which study the effect of heat and temperature on labor, radiation and matter.

Theory of Electricity and Electromagnetism

During the 18th century, research on electricity and magnetism was another major point of study for physics. Among the findings, there is the suggestion of philosopher and statesman Francis Bacon, that the electric charge has two sides, a positive and a negative, which, being equal, collide and are different, attract each other.

Bacon also developed a new method of study for science in his publication Novum Organum, in which he specified certain stages of research based on empiricism, studies conducted through experience and experience:

  1. The description of the phenomena.
  2. The classification of facts into three categories or tables: first , the circumstances given in conducting the experiment; second , the absent circumstances, moments in which the phenomenon does not appear; third , the variables are present at different levels or degrees of intensity.
  3. Table of rejection of results that are not linked to the phenomenon and the determination of what is related to it. 

Another decisive experimentalist in this field was the British Michael Faraday (1791-1867). In 1831 he made his discovery through induced currents. He experimented with a wire circuit whose current was held if it was moving close to a magnet or if the magnet was moving close to the circuit. This would lay the groundwork for the generation of electricity by mechanical procedures.

In turn, James Clerk Maxwell made a fundamental contribution to electromagnetic theory, defining that light, electricity and magnetism are part of the same field, called the “electromagnetic field”, in which they remain in motion and, in turn, are able to emit transverse waves of energy. Later, this theory would appear as an important reference for Einstein’s studies.

Modern physics

After the discovery of subatomic particles, electrons, protons and neutrons and electromagnetic theory, the entrance to the 20th century would also be composed of theories relevant to contemporary times. Thus, among the most outstanding figures of that time is Albert Einstein.

Einstein’s studies demonstrated the existing relativity by measuring velocity and its relationship to time, space and the observer. For Einstein’s time, the speed of an object used to be measured only in relation to the speed of another object. 

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The theory of relativity special Einstein revolutionized the concept of space-time that existed previously and was published in 1905. It determined that the speed of light in vacuum was independent of the motion of an observer, that is, that remains constant and that the perception of space-time is relative to each observer. 

In this way, an event that occurs in two parts simultaneously may be perceived differently by two observers who are in two different places. The law suggests that if a person could move at high speed, the perception of spacetime would be different from that of a person at rest and that nothing would be able to match the speed of light.

As for the theory of general relativity published in 1915, he explains that large-volume objects like planets are capable of doubling spacetime. This curvature is known as gravity and is capable of drawing bodies to them. 

Quantum Mechanics

Finally, within the most recent and significant fields of study, quantum mechanics stands out, focused on the study of nature at atomic and subatomic levels and its relationship with electromagnetic radiation. It is based on the observable through the release of different forms of energy.

In this field, Max Planck, known as the father of quantum theory, stands out. He found that radiation is emitted in small amounts of particles called “quanta”.

He later discovers Planck’s law that determined the electromagnetic radiation of a body at a certain temperature. This theory was developed in the early 20th century, almost on a par with Einstein’s theories.

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