Charging by Friction
Rubbing two different materials together, a process known as
charging by friction (AKA charging by rubbing), is the simplest way to give
something a charge. This is what you do every time you drag your feet along a
carpet so you can reach out and zap someone's ear.Example : Rub a glass rod with a piece of silk. Explain what
happens. This is the same sort of situation as the one above. In this case the
silk holds onto the electrons more strongly than the glass. Electrons are
ripped off of the glass and go on to the silk. The glass is now positive and
the silk is negative.
Charging by Conduction
Conduction just means that the two objects will come into actual physical contact with each other (this is why it is sometimes called“charging by contact”).
Charging by Induction
It is possible to charge a conductor without touching it. You do have to follow some special procedures. Most important is the use of a grounding wire. A grounding wire is simply a conductor that connects the object to the ground. Think of the earth as a huge reservoir of charge… it can both gain or donate electrons as needed. Depending on what the situation is, either electrons will travel up the grounding wire to the object being charged, or travel down to the ground.