In this experiment, you will see the static shower of the puffs.
Things Required:
Section of Lucite
Two thick books (or stacks of smaller ones)
Puffed cereal or pieces of plastic foam
Directions:
Place two thick books about 8 inches apart on a tabletop. The top of the books should reach several inches above the table.
Scatter puffed cereal grains or pieces of plastic foam in the gap between the books. Place a piece of Lucite across the gap so that it may rest firmly on the books.
Rub a piece of wool or felt across the surface of the Lucite. What happens to the grains below? If you observed some movement, try rubbing your hand back-and-forth across the Lucite. To prevent the plastic section from slipping, you’ll need to steady the Lucite with your other hand. Do the grains still move?
This Is What Happens:
As you stroked the plastic, it became charged through contact. The negative field of the plastic affected the charge balance in the cereal grains. The nearby negative charges of the grains migrated towards the farther side of the grain. This created a positive end of each grain that was attracted to the plastic. This attraction caused the grains to jump upwards and cling to the Lucite.
While the grains were attached to the Lucite, the balance changed. Electrons in the plastic moved onto the grains. Although it took them several movements to transfer yet, this flow eventually cancelled the positive surface of the grains. Without this opposite charge, the grains were into longer attracted to the plastic. They dropped off because of their weight.
