What is Physics?

We explain what physics is and the four basic domains in which it is divided. In addition, their interests and different branches of study.

1. What is Physics?

Physics, from the Greek physis (“nature”), is the natural science that deals with the study of four fundamental concepts of reality , in which the laws that govern the universe seem to stand: energy , matter , time and the space, as well as the interactions between them.

Physics is one of the oldest academic disciplines , whose roots date back to the beginning of civilization, when man began trying to understand the forces that govern the world around him.

It is a discipline both theoretical (description of the laws of the universe) and experimental (implementation of hypotheses regarding these laws), and adheres to the model of verification and legitimation driven by the scientific method . It is one of the fundamental or central sciences, within whose field of study chemistry, biology and electronics often converge , among others.

Initially physics was part, like so many other sciences, of the natural philosophy or philosophy of antiquity, but from the Scientific Revolution of the 17th century it emerged as an independent field, interested in the fundamental laws of reality and using formal language of mathematics to express them. At present, however, physics is one of the disciplines that most contributes to the change of the scientific, industrial and technological paradigm .

Physics as we know it today is divided into four basic domains, that is, four approaches to the phenomena of nature, based on two fundamental considerations: the size of matter and the speed of its movement. These four domains are:

• Classical Mechanics . It deals with perceptible movements in macroscopic bodies, whose speeds are very small compared to the speed of light . It is divided in turn into Newtonian mechanics, which responds to Isaac Newton’s studies, and analytical mechanics, more complex than the previous one.
• Relativistic mechanics . Based on the theoretical developments of Albert Einstein during the twentieth century, it resembles the classical in its deterministic character, but moves away from it in two essential postulates: the theory of special relativity, which describes the behavior of bodies that move at high speeds, close to the speed of light; and the general theory of relativity, which adds a relativistic theory of gravitation ( gravity ) to the previous one .
• Quantum mechanics . It deals with very small-scale mechanical systems, and with the forces that exist in such microscopic systems, such as atoms and fundamental particles.
• Theory of the quantum field . Also called relativistic quantum theory, it attempts to unify relativistic and quantum mechanics into one theory for everything. Although many aspects seem to operate in their postulates, the General Relativity Theory has not been unified to the equation .

2. What does physics study?

Physics deals with the fundamental laws of the universe , that is, to understand and describe the mechanics with which reality operates. This goes through the four fundamental interactions known:

• Gravity . The force of attraction between two or more bodies provided with mass, capable of extending over enormous distances.
• Electromagnetism . The force of attraction or repulsion that manifests between electrically charged particles, as well as electric and magnetic fields.
• Weak nuclear forces . Also called weak interaction, it is the force that occurs between fundamental particles at a very short distance, and is responsible for atomic decay and radioactivity.
• Strong nuclear forces . It is a huge force of attraction that holds neutrons and protons together in the nucleus of the atom, overcoming electromagnetic repulsion among the latter (positively charged).

3. Branches of physics

Physics comprises a set of subdisciplines that are:

• Acoustics . Branch of physics interested in the nature of sound: its propagation, its origin, etc.
• Electromagnetism . It deals with the electrical and magnetic phenomena of matter and energy fields of that nature that exist in space.
• Mechanical . Mainly interested in the movement of bodies (mainly solid) and the relationships of force between them.
• Fluid mechanics . Similar to the previous one, but is responsible for studying the dynamics of physical fluid systems: liquids and gases.
• Optical . This branch is interested in light and its mysteries: its nature, its propagation, its properties, etc.
• Thermodynamics . Branch dedicated to the study of energy and heat, mainly, as well as the systems that preserve or transmit them.
• Cosmology . Interested in the study of the universe, that is, of the laws that govern it, of the traces of its origin and of the forces between the celestial stars.
• Quantum mechanics . Its main object of study is the fundamental particles of matter, that is, atoms and subatomic particles .

4. What is chemistry?

Chemistry is a discipline that presents points of contact with physics , particularly in its interest in the subject: chemistry studies the methods of its composition and the reactions that can occur to other chemical substances or to the presence of heat and The other forms of energy.

Therefore, chemistry has a more focused perspective than physics, and it does not come from natural philosophy, but from medieval alchemy that sought among other things to convert common elements into precious metals.