Displaying lines of electric flux

In the experiment P3.1.3.1, small particles in an oil-filled cuvette are used to illustrate the lines of electric flux. The particles align themselves in the electric field to form chains which run along the lines of electric flux. Four different pairs of electrodes are provided to enable electric fields with different spatial distributions to be generated; these electrode pairs are mounted beneath the cuvette, and connected to a high voltage source of up to 10 kV. The resulting patterns can be interpreted as the cross-sections of two spheres, one sphere in front of a plate, a plate capacitor and a spherical capacitor.