Electrostatic Zoo is a free program that simulates the interaction between charged particles, and illustrates the electric fields generated as a result.

Charges in the Zoo interact via the Coulomb force, with a Pauli repulsive force at close distances and a damping force proportional to velocity.

The fields can be visualized in two ways: a "grass-seeds" representation (click on "Idraw-Efield"), or a traditional vector field representation (click on "Field Visualization-Efield"), in addition to the real time renderings of the local field around each particle.

Many of the properties of the Zoo can be modified, including the number of charges, the value of the charge on each particle, and the time step of the simulation. Some of the functionality is described as follows:

Use Start button to start simulation (lowest panel). Use Pause button to pause simulation (lowest panel). Click and drag on any particle to change its position. Use the "dt" slider to change the time step.

Use "Idraw-Efield" to get a "grass-seeds" representaton of the electric field. Use "Field Visualization-Efield" to get a vector field representaton of the electric field. Select and right click and choose "remove" to remove charge.

Use the "hand" in the "Physics" panel with the sphere icon selected to add a charge with the properties specified in that panel. Use the "hand" in the "Physics" panel with the icon selected to add an electric field line with the properties specified.