Two fixed charges are shown in black. Drag the small green test charge around the screen and observe the relationship between the force vector and the field lines. Are there any locations where the particle is on a field line and the force vector is not tangent to it?
Like charges Unlike charges
Click here to return to the original set-up. Make a prediction in the box below of how the particle will move in response to the field when you click on "play". You must make a prediction before the simulation will play.

What did you observe? How did the result compare to your prediction? What can you learn from this?

Exercise created by Scott Bonham, Western Kentucky University.
Physlet by Wolfgang Christian, Davidson College