5B10.10 - Van de Graaff Hair Radial E Field
Demonstrate static electric repulsion.
Pull out the VDG and discharge globe. Be sure to connect the discharge globe to ground (either through the connection on the VDG or with a direct grounded plug). Make sure the discharge globe begins 2 inches from the top globe of the VDG. Connect the two discharge rods (the needle-point and the spherical rod) to ground as well. Make sure to grab the insulated stool if the instructor plans to have a volunteer perform the demo. Run the VDG to ensure it is discharging through the discharge globe before you begin the demo. See operation instructions for further detail.
Make sure VDG top globe is grounded. Pull discharge globe away from the globe of the VDG. Before you start the demo with a student volunteer, ensure they have no medical devices, smart phones, metal implants, watches or the like. Have a student stand on an insulated stool about 1 foot from the cart and have them firmly place and keep their palm on the globe of the VDG. Take care to look around and make sure nothing is within 10-12" of the student's body, including her shoes to the cart or floor. Turn on the VDG. As the hair becomes charged, it will stand on end. This demo works best with fine, freshly-washed, 3-6" long hair. Be patient, because it sometimes takes a minute or more. Also, while you are charging up, you may want to shake your head slowly. Using a volunteer for this demo is encouraged. If all goes well, the student's hair will become charged and repel itself. Turn the VDG off and with the pointed lightning rod attachment, slowly drain the charge off of the VDG until the student is not longer charged. They may now safely remove their palm and step down from the stool.
This demo can also be used with syntnetic hair. The hair must be ionically charged first, using an isolated insulated needle point charger plugged into the top globe of the Van de Graaff. The bowl that the Pom-Pom is connected to must be grounded as well using an alligator clip and banana cable plugged into ground. Carefully brush over the entire surface area of the the PomPom until it is obviously picking up some charge. Then "comb" the pom-pom to deposit charge throughout the strands of plastic. Carefully remove the PomPom from the stand and plug it into the banana plug on the top of the Van de Graaff. The ionic charge will last 4 to 6 hours if the operator is careful not to discharge the plastic strands with the opposite charge ions formed from the bottom globe of the Van de Graaff.