Electric Field Mapping

Disclaimer...this is not, strictly speaking, an inquiry lab, but I LOVE this lab. I think that it helps the students to see what is generally a very abstract thing. And it's fun.

Materials Available:

  • Disposable baking pans, both the metal bottom and the plastic top.
  • 9V Batteries, one per group.
  • multimeter, one per group.
  • wire leads, two per group.
  • water
  • graph paper

What to find:

  • Use the fact the electric field lines run perpendicular to equipotential lines to map the electric fields of several different configurations. Start with a single pair of "point" electrodes, and then explore other configurations.


  • Use the metal pan to cut out electrode pieces. Place a piece of graph paper under the plastic lid and fill the lid with about 1cm of water. Attach one electrode to one side of your lid and another directly across on the other side. Attach each electrode to the battery, creating an electric field in the pan of water. Touch one lead of your multimeter (set on the 20V setting) to one electrode and place the other lead in the water. You should see a voltage reading on your multimeter. Move the lead around to see how the voltage changes.
  • Get a second piece of graph paper and mark where the place that matches the electrode positions on the graph paper that is under the plastic lid. You will map equipotential and electric field lines on this piece of graph paper. Choose a starting voltage and move your lead around to find the line of equipotential. Note the position on the graph paper and draw in this equipotential line on your piece of graph paper. Do this so that you have equipotential lines drawn at 2cm intervals across your graph paper.
  • When you have sufficient equipotential lines, sketch in the electric field lines.
  • Repeat with at least 2 more configurations of electrodes.

What to submit:

  • Submit your drawings clearly labled with voltages on the equipotential lines and with the direction of the electric field indicated on your electric field lines.