Electric fields are an important topic in physics, and one that’s particularly challenging to demonstrate clearly in the classroom. You can find several demonstrations of this in section J3 of our catalog, wherein we qualitatively trace out electric field lines around a Van de Graaff Generator or a Wimshurst Machine, and have a variety of ways of gathering electrostatic potential and showing how it interacts with conductors in different configurations. One very popular one, demonstration J3-08, uses paper streamers around one or two Van de Graaff Generators to show how the fields bend and interact.
Understanding electric fields is important for everything from understanding the structure of matter to communications technology to the behavior of living cells. The electric field is a vector field of the electrostatic force (strength and direction) on a hypothetical charge placed at any given point. Thus, it is usually measured in Newtons per Coulomb or Volts per Meter.
We have an article in our Directory of Simulations with several ways of experimenting with electric fields virtually. Try out this one at oPhysics, by Tom Walsh. You can model our paired Van de Graaff Generators above as a pair of identical charges, and see the structure of the resulting electric field. Compare how this would change if one of the generators had the opposite charge, or if we used four generators instead of two.
Check out other simulators as well, and see what you can find!