This interactive is designed to give you a feeling for how electric charges create electric fields and electric potentials. We hope that you may gain some intuition -- not just get the numbers for a homework problem -- by using it.

Create an electric field

Check the Fixed button in the "Add Charges" control panel, and move the cursor into the large grid area. You will see a little ball stuck to your cursor. The ball carries an electric charge, the size and sign of which you can control with the Charge slider bar. As you move the charge across the grid, little arrows will appear and change size and direction: these arrows show the electric field at each point of the grid.