The International Association of Weights and Measures has approved quantities that are used to calculate time, distance, mass of objects, and the strength of light energy One of the units of measurement in the SI system is the mole With its help, the amount of a substance is determined, or more precisely, the content of molecules, atoms or ions in one gram under normal physical conditions From the course of physics and chemistry it is known that per 1 mole there are as many tiny particles as there are atoms contained in 0012 kg of carbon nuclide with atomic mass 12 The calendar of solemn dates includes holidays dedicated to various mathematical constants - the number Pi (International Pi Day), square root, etc October 23 is celebrated as Mole Day Mole Day appeared in 1991 thanks to chemists from Wisconsin One of them, Maris Oyler, established the National Moth Foundation on his own In 1991, a holiday dedicated to one of the units of the system of weights and measures arose The date of Prayer Day was not chosen by chance It is directly related to the Avogado constant - the number of atoms (molecules or ions) contained in 1 mole of a substance The approximate index of this constant is 602⋅10 to the 23rd power Therefore, Prayer Day is celebrated twice a day on October 23 - at 6:02 in the morning and the second time at 18:02 in the evening Molecular physics studies the composition of substances in various states - from liquid and solid to gaseous To solve problems, this science uses the methods of thermodynamics and statistical dynamics The first branch of molecular physics was the kinetic theory of gases in 1858, which was developed by Ludwig Boltzmann together with other scientists Long before them, in 1811, the Italian chemist Amedeo Avogado suggested that at a given pressure and temperature, the volume of a gas, regardless of its nature, is proportional to the number of atoms or molecules Today this constant quantity is called a mole The term mole, derived from the word “molecule,” came into use at the beginning of the twentieth century Wilhelm Oswald, who became a Nobel laureate in 1909 for his discoveries in chemistry The unit of measurement was introduced into the SI system in 1971 20 years after this event, a holiday was established in honor of the moth The celebration is celebrated by scientists, laboratory assistants, chemistry and physics teachers During Mole Day, teachers conduct competitions, conduct experiments with students, and organize competitions for solving entertaining problems in which moles appear Thanks to the initiative of chemistry teacher M Oyler and funds collected by the National Foundation, the winners of school and university Olympiads receive valuable prizes and awards On Moth Day, seminars and conferences are held, and feature articles are published in scientific journals of the American Chemical Society and other organizations