Electric Fields

1. Visualize Electric Field Lines

1. Obtain an electrostatic generator (such as a handheld Static Genecon or a van der Graff generator), a pair of electrodes arranged in a concentric circle configuration, and a pair of electrodes arranged parallel to each other.
2. Obtain a Petri dish or an observation tank, fill it with oil (such as Castor oil), and add electrified/polarizable powders (such as semolina seeds) in the oil.
3. Load the electrodes with the parallel electrode configuration onto the observation tank holder. Connect the two electrodes to the "−" (ground) and "+" (charged) terminals of the electrostatic generator, respectively, as in Figure 1. The connection can be made by cables with clamps.

Figure 1: Diagram showing the schematics of two copper wires connected to an electric generator, the other ends (dipped into an oil) of the wires are connected to a pair of parallel electrodes.

4. Turn the crank of the generator which will put positive charges on the electrode connected to the "+" terminal. Make at least 5 full turns. Observe the behavior of the powders.
5. Use a cable to directly short the "−"and "+" terminals to neutralize the charges. Disconnect the electrode from the terminals.
6. Next, load the concentric circle electrode configuration onto the holder and connect the electrodes to the terminals of the generator again, as shown in Figure 2. Stir the oil in the dish to randomize the powders.

Figure 2: Diagram showing the schematics of two copper wires connected to an electric generator, the other ends (dipped into an oil) of the wires are connected to a pair of electrodes shaped as an inner ring and an outer ring respectively.

7. Crank up the generator (at least 5 turns) and charge the electrodes, and observe the behavior of the powders in the dish.

2. Effect of Electric Field

1. Obtain an empty soda can and rest it on its side (so it can roll freely) on a table
2. Obtain an acrylic rod; rub it with fur to charge it.
3. Bring the rod close to the empty soda can, and observe the response of the soda can.
4. Tear a small strip of paper and bring it to the charged rod, observe its behavior.