Table of Contents
Richard Bonnaire
Universite Pierre et Marie CURIE
To the list of Colos applications
Maxwell is an application which allows the user to observe the velocity distribution of colliding particles in a 2D adiabatic container.
The display shows the colliding particles and controls to set the parameters of the simulation: initial velocity of the particles limit between fast and slow particles when the Maxwell's demon is acting.
Three histogram diagrams display dynamically the velocity distribution in the two compartments defined by the demon's action and also the overall distribution.
Maxwell is intended to present the dynamic phenomena underlying the mathematical formulation of the Maxwell-Boltzman distribution of velocities.
It is difficult to show that the mathematical formulation of the velocity distribution is related to a dynamic behaviour of a collection of colliding particles in an equilibrium state. The approach taken here is to start with particles of the same initial velocity and to let them equilibrate through interparticle collisions. To emphasize the relation with the concept of entropy (a difficult one for the students) the action of a "demon" described by maxwell can be turned on and off during the simulation. In order to give a better feeling of the phenomena specific colours are associated with ranges of velocity. It is then easier to follow the changes of velocity during the collisions. The colour code is also used for the histogram representation.
Even with a small collection of particles (maxwell works with 1 to 250 particles) the distribution of velocities is clearly shown. It is only possible to have a fluidity of the movements by using powerful workstations (even on HP 9000 / 370 workstation the movements are not smooth enough).
maxwell is intended to be used in the university curses with students in the first of second year. It can be used by a teacher for a demonstration or in a self-exercising way by students.
Evaluation is not yet done.