We study ODE event driven models and show how they can be used to detect hard disk collisions in models such as the ideal gas and Newton's cradle. We also introduce discrete maps and Poincare sections.
The Newton's Cradle Model is a simulation of the classical executive's toy. Multiple collisions among the balls are simulated using a single event with arrays.
F. Herrmann and P. Schmälzle, "A simple explanation of a well-known collision experiment," Am. J. Phys. 49, 761 (1981)
The following models use ODE events to detect collisions between hard objects (disks or spheres).
Additional models may be be posted for self-study.
The Balls In Box Model was created by Francisco Esquembre using the Easy Java Simulations (EJS) modeling tool. It is based on a Java program from the Statistical and Thermal Physics Project. You can examine and modify this compiled EJS model if you run the model (double click on the model's jar file), right-click within a plot, and select "Open Ejs Model" from the pop-up menu. You must, of course, have EJS installed on your computer.
Information about Ejs is available at: <http://www.um.es/fem/Ejs/> and in the OSP comPADRE collection <http://www.compadre.org/OSP/>.