The description of the free expansion of the ideal gas is obtained with the aid of the model of the ideal gas implemented in a PIII computer. The gas was iniatilly located in the left half of a box of volume V, by means of an insulating partition wall. It was developed a function that allows to generate the number of particles desired with random values of the initial speed and of the position. It is obtained, that by the time of relaxation the number of particles in the left part of the box is equal to N/2 and that the value of this interval depends on the nature of the gas and the temperature. It is proved that the Maxwell distribution of speeds gives an adequate description of the behavior of this system. The entropy of the system with a number of particles relatively big, is calculated with the aid of a function developed for that purpose. It was also shown that the entropy of the system grew when the system reached the equilibrium and that the bigger fluctuations are not very probable even for a long time of observation.
modelling; model-based teaching; ideal gas; Maxwell distribution of speeds; entropy; fluctuations
