15.1. Static Electricity http://www.ck12.org
FIGURE 15.2
Common items that conduct electric cur-
rent: aluminum foil, paper clips, coins,and
nails.Answer: Since like charges repel each other, they distribute themselves in a symmetrical fashion as far from each
other as possible on the surface.
Insulators
Materials that do not conduct electric current are called non-conductors, orinsulators. Glass, wood, plastic, and
rubber are examples of insulators, as shown inFigure15.3. Insulators are very important in protecting us from the
dangers of electricity, since they do not permit a current to pass through our bodies.
FIGURE 15.3
Common insulators; a glass rod, red plas-
tic insulation on a hand tool and a piece of
wood. Why do you think the hand tool has
insulating handles?http://www.youtube.com/watch?v=pyfM_fKSICE
Check Your Understanding
If similar charges are placed on a spherical insulator, will they move as far from each other as possible?
Answer: They won’t move at all. They will remain wherever they are since they cannot move freely on an insulator.
Now that we know a bit about the structure of the atom and about conductors and insulators, we can describe