Electric charge

Transfer of charge (electrons)

when you rub a ruler t against a neutral material like wool, cotton or hair, the ruler becomes electrically charged. this creates a force around it that can attract the paper pieces and make them stick to the ruler.

gain electrons (negative charge)
lose electrons (positive charge)

Like charges
quickly pull the tape strips off a desk and it will become charged, bring the, near each other. pulling the strips of tape off the desk gives them the ability to repel each other because they have accumulated electric charge. because they were prepared in the same way they have the same charge which always repel each other.


Unlike charges

now stick on piece of tape on the desk and stick the second one directly on top of the first one and pull both strips off the desk together gently rub them with your fingers to remove any charge they had. now quickly separate the two pieces of tape and bring them close together. you’ll notice the strips attracts each other. this means they don’t have the same charge they must have opposite charges (positive and negative)


an electrostatic force is the force of repulsion or attraction between two electrically charged object.

where do charges come from?
-matter is made up of atoms

positive charges: glass and wool
negative charges: rubber and plastic
the matter normally contains both types of charge, the two kinds of charges did not appear alone but in pairs.

electrons that orbit the farthest from the nucleus experience the weakest electrostatic force.



Conductors and Insulators:
a material that allows charges to move easily is an electric conductor
-metals are good conductors because at least one electron of each metal atom can be removed easily
Examples: copper and aluminum, plasma (consists of negative electrons and positive ions), and graphite

A material through which a charge will not move easily is called an electric insulator
it limits the movement of charge along with the object so the charge remains localized. the object is only charged where it was rubbed.
Examples: glass, dry wood , plastics, cloth and dry air.