Materials Charging by Induction Lab-Cuyamaca College .

The materials I used in the experiment are aluminum pan, Styrofoam plate, Styrofoam cup, tape, and string. The steps in building electrophorus that works effectively is as follows:

 

Step 1: I place the aluminum pan face up on the table and tape the Styrofoam cup upside down to the middle of the pan. In this case, the cup will serve as the insulating handle.

Step 2: I rub the wool on flat sheets of Styrofoam plate for a minute which is necessary for building up static electricity on flat, insulating material.

Step 3: The charged Styrofoam sheets were placed on the table. Then, I held the pan by the handle and lowered it onto the Styrofoam. After that, I brought my finger close to the aluminum pen and I got a small shock.

Step 4: After that, I brought my finger close to the aluminum pen and I got a small shock. Once it stopped giving me small shocks, I lifted it up and away from the Styrofoam. To make sure it will not stop working just rub the wool on Styrofoam sheets again.

Step 5: I tried to hang the tape on the edge of the table and observed that it suddenly moved.

Rubbing the wool against the Styrofoam sheets makes the wool lose some of its negative charges to the Styrofoam and now, Styrofoam has extra negative charge. The Styrofoam is an insulator that is stuck in place. When I put the aluminum pan on top (near charged Styrofoam) , the charges flow wherein the negative charges repel and it attracts positive charges. Now, the negative charge ends up on top of the pan. As I observed, negative charges repel from one another that the tape moved. Touching the pan helped the setup to provide a path for repelled negative charges to flow away from the pan. The pan loses some negative charge and now has extra positive charge. Meanwhile, lifting it up, the positive charge can spread evenly out of the pan and the effect is like repulsion that the tape moves. This process is called charging by induction wherein there is no transfer of negative charge on the aluminum pan. The negative charges just stayed there and repelling force rearranged the charges on the pan.