When young Max Planck told his teacher that he wanted to continue to study theoretical physics, he smiled and assured him that the scientists had nothing to do there - all that was left was to “clean up the roughness”. Alas! Thanks to the efforts of Planck, Niels Bohr, Einstein, Schrödinger and others, everything is turned upside down, and so thoroughly that you won’t go back, and there is impassability ahead. Further - more: among the general theoretical chaos suddenly appears, for example, Heisenberg's uncertainty. As they say, this was just not enough for us. At the turn of the 19th and 20th centuries, scientists opened the door to an unknown region of elementary particles, and there Newton's usual mechanics failed.
It would seem that “before”, everything is fine - this is the physical body, here are its coordinates. In “normal physics” one can always take an arrow and precisely “poke” it into a “normal” object, even a moving one. A slip is theoretically excluded - Newton’s laws are not mistaken. But now the object of study is becoming smaller - a grain, a molecule, an atom. First, the exact contours of the object disappear, then probabilistic estimates of the average statistical velocities for the gas molecules appear in its description, and finally, the coordinates of the molecules become “average”, and the gas molecule can be said to be either here or there, but most likely somewhere in this area. Time will pass and Heisenberg’s uncertainty will solve the problem, but then, and now ... Try to get into the object with a “theoretical arrow” if it is “in the region of the most probable coordinates”. Weak? And what is this object, what are its sizes, shapes? There were more questions than answers.
But what about the atom? The well-known planetary model was proposed in 1911 and immediately raised a lot of questions. The main one: how does a negative electron stay in orbit and why does it not fall on a positive nucleus? As they say now - a good question. It should be noted that all theoretical calculations at that time were carried out on the basis of classical mechanics - Heisenberg's uncertainty has not yet taken pride of place in atomic theory. It was this fact that did not allow scientists to understand the essence of atom mechanics. The atom was saved by Niels Bohr - he gave it stability with his assumption that the electron has orbital levels, at which it does not radiate energy, i.e. does not lose it and does not fall on the core.
The study of the continuity of the energy states of an atom has already given impetus to the development of a completely new physics - quantum physics, which was started by Max Planck back in 1900. He discovered the phenomenon of energy quantization, and Niels Bohr found application to him. However, in the future it turned out that describing the atom model by the classical mechanics of the macrocosm that we understand is completely inappropriate. Even time and space in the conditions of the quantum world takes on a completely different meaning. By this time, attempts by theoretical physicists to give a mathematical model of a planetary atom ended in multi-story and ineffective equations. The problem was solved using the Heisenberg uncertainty relation. This surprisingly modest mathematical expression relates the uncertainties of the spatial coordinate Δx and velocity Δv to the particle mass m and the Planck constant h :.
Δx * Δv> h / m
From this follows the fundamental difference between the micro- and macrocosm: the coordinates and velocities of particles in the microworld are not determined in a concrete form - they are probabilistic in nature. On the other hand, the Heisenberg principle on the right side of the inequality contains a very concrete positive value, which implies that the zero value of at least one of the uncertainties is excluded. In practice, this means that the speed and position of particles in the subatomic world is always determined with an error, and it is never zero. In exactly the same perspective, the Heisenberg uncertainty connects other pairs of related characteristics, for example, the uncertainties of energy Δ and time Δt:
ΔΔt> h
The essence of this expression is that it is impossible to simultaneously measure the energy of an atomic particle and the moment of time at which it possesses it, without uncertainty of its value, since energy measurement takes some time, during which the energy randomly changes.