The ambition of physics might seem exorbitant, but the progress of this science since the physical laws began to be explained in the 18th century, is in charge of refuting this judgment. The study of physics demands a clear understanding of the objectives that this science is raised and the approach with which it is faced. In the first sections of this chapter I will try to give some ideas to facilitate this understanding, although such ideas will be better assimilated as progress is made in the study of physics, a science that, due to the breadth of the field of phenomena it studies, becomes It is usually subdivided into differentiated areas of specialization, and I will provide a historical outline of the development of physics, from the speculative and almost always incorrect ideas of the ancient Greeks, and up to the great revolutions of the early 20th century and the horizons currently open. Finally, I will define the concepts of magnitude and measurement unit, fundamental in physics, and I will clarify the meaning of some mathematical symbols that I will have to use repeatedly in various chapters.
Human beings capture the world through our senses and, at least initially, consider the sensory properties of matter (color, texture, weight, etc.). These properties can suffer modifications of two types. physics and chemistry. The former only temporarily alter the appearance of the bodies and are not exclusive to their particular nature. While the latter produce permanent changes and vary with the nature of the bodies. An example of a physical property could be the ability of a body to experience an attraction towards the ground when it is in the terrestrial gravitational field. It is a physical property, because, on the one hand, it is not an exclusive particularity of that body and on the other, it does not depend on its intimate nature. Thus, gravitation is a physical phenomenon. On the other hand, the ability to burn in the air of a certain substance is a chemical property, since only certain substances can burn, and when a substance burns its nature undergoes an irreversible transformation. Combustion is, therefore, a chemical phenomenon. The distinction between what is a physical phenomenon and what is a chemical phenomenon is not always so clear. there are areas of study that can be included in both physics and chemistry, so often both physics and chemistry textbooks present them. for example, the equations that govern the behavior of gases and deal with changes of state. On the other hand, the study of atoms arose in the field of chemistry and belonged to that field until, at the end of the 19th century, After discovering the existence of the electron, it became part of physics. In any case. Physics as a science is characterized not only by the phenomena it studies, but also by the methods with which it performs that task. In fact, it is more appropriate to characterize physics by its methods than by its object.
Physics is an experimental science, which means, on the one hand, that it is based on the observation of natural phenomena and, on the other, that any physical theory has its ultimate test of validity in experiment. The observation of a phenomenon already implies a first idea about its nature, since it focuses on the aspects of it that seem relevant. For example, to study the fall of bodies, the times taken by bodies of different shapes and weights would be noted. in falling the same speed in a vacuum as in the air, etc. but it would not make sense to write down the color of the bodies, since, obviously, this is an irrelevant aspect for the studied phenomenon. On the other hand, the phenomenon that the physicist studies is not so much the one that occurs naturally as the one caused in the laboratory: the physicist would not wait for the accidental fall of a body to take place to study the grave, but would prepare a suitable scenario to study the fall of bodies chosen according to certain characteristics.
written by orlando torres .