Main Catalogue - VUOTOTECNICA - #4

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HISTORY OF VACUUM The problem of the existence and definition of vacuum has captured the interest of the brightest minds in philosophy and science ever since ancient times. the hellenistic era The Alexandrine mechanics had studied the usefulness of compressed air (Philo of Byzantium’s Pneumatics, 250 B.C.). Their stance was midway between the supporters and critics of the vacuum theory. According to the Alexandrines, it was not possible to have vacuum in large volumes, but only scattered between one particle and another (Latins would then call it vacuum intermixtum). This way, they could easily explain the compressibility and elasticity properties of air. ancient GREECE The Aristotelian system of the world According to Ancient Greek philosopher Democritus, the universe is composed of eternal and unmutable elements called atoms (i.e. indivisible). The natural processes and the becoming of reality were explained by Democritus as the movement of atoms in an infinite void. Within this void, atoms would move in a straight homogeneous motion, until colliding with other atoms. Therefore, according to Democritus, atoms and vacuum were the two primary realities composing the world. A totally different conception came from Aristoltelian dynamics. According to Aristotle, motion is not caused by a body, but by the medium in which the body is in. Once released, a projectile moves because pushed by a column of air, which constantly seeks to occupy the void left by the projectile during its passage. Therefore, a body would always be subject to a force during motion, and its speed would be proportional to this force and inversely proportional to the medium’s resistance to motion. This would mean that in an vacuum, resistance to motion would be zero and the speed of the body would be infinite, i.e., the body would have the gift of ubiquity. Therefore, Aristotle believed in the impossibility of vacuum: “Nature hates vacuum”. Democritus (5th century B.C.) Aristotle (384 - 322 B.C.) 3