Torricelli's experience: essence and meaning

Since ancient times, human minds have tried to understand the nature of the surrounding world, the laws of nature, the history of its origin and destination in this universe. This aspiration has generated completely different pictures of the world in different epochs and in different corners of the planet: the personification of natural elements with a divine beginning, the idea of the struggle of darkness and light in Persian Zoroastrianism, the creation of the world and the apocalypse in Judaism, and much more.

However, the real rudiment of rational scientific knowledge of the world is the breakthrough accomplished by the thinkers of ancient Greece. Thus, one of the most important concepts of Aristotle was the introduction of the concept of "emptiness", complete emptiness - a space where nothing exists. The idea of emptiness was a frightening phenomenon for the philosopher, however, in his opinion, and impossible in nature. After all, the empirical data available to man then could not reveal the concept of an absolute vacuum, and all the ordinary space is filled with air. For example, if you try to blow air from a hollow tube, then its walls will shrink. That is, inside not only the emptiness, but also the space itself will remain. And the water in the pipes always rose behind the piston, not allowing the emptiness to form.

Torricelli experience: description

The idea that there can not be a space in the world that is not filled with liquid, solid or gaseous matter has successfully lived up to the New Age - the era of human thought and scientific achievements. It was then that people again regained their faith in the possibility of practical and rational knowledge of the world. Torricelli's experience, however, was not only the result of scientific research, but also of chance. During the construction of the fountains at the palace of one of the dukes of the famous Medici dynasty, it was noticed that the water in the pipes really rises, filling the emptiness, but only up to a certain height, after which it ceases its movement. This fact could not but arouse interest in the homeland of the Renaissance.

Explanations were turned to the physicist and mathematician Galileo Galilei, widely known at that time (and even more famous today). However, without finding an acceptable answer in logic, he decided to resort to the experimental path. The experiments were commissioned to put two of his students - Viviani and Torricelli. Interesting results reached the second. Torricelli's experience suggested placing a certain volume of mercury in a glass tube (it is heavier than water, therefore it shows more evident results with small volumes of capacity) so that air does not get there. At the same time, the upper end was sealed, and the open lower was placed in a cup of mercury. It turned out that mercury also did not fill the entire space of the tube, leaving a certain amount of emptiness on top. However, these empirical knowledge did not immediately receive its theoretical justification.

Explanation of experience

The experience of Torricelli soon became known to the whole enlightened Europe, the scientists of which argued about the nature of this phenomenon. The explanation of the fact was given to Evangelista Torricelli himself. Since there was no air in the closed glass tube over the mercury, he explained that the height of the mercury column is determined literally by the pressure of air on the mercury in the cup, forcing it to go more and more into the glass tube. For the first time, atmospheric pressure was discovered experimentally. Torricelli's formula stated that this pressure corresponds to the height of the mercury column: P atm = P mercury. Further studies were picked up by the Frenchman Blaise Pascal, who expressed in numbers the dependence of the height of the pillar on the severity of the air at a particular moment, thus enabling mankind to determine atm. pressure.