Part 2: Calculation of a point charge using the electric field Getting started: Go to phet.colorado.edu. On the home scree. go to and select "Physics." You should then see a list of simulations. Choose Fields" and download the simulation. Take some time to familiarize features before beginning the experiment. 1. Check the "Electric Field" and "Grid" boxes in the simulation C positive charge at a point in the grid (it may be easier to place the two major grid lines). 2. Check the "Values" box in the simulation control window. Place yellow dots) around the positive charge at 0, 90, 180, and -90 degree the electric field, E, at these points