LESSON: Introduction to Electrical Charge
LESSON: Introduction to Electrical Charge
Watch the following video to find out what causes electrical charges:
Electrons can be transferred fairly easily between objects, but protons are more fixed. Usually the positive protons and the negative electrons will balance out, and objects will have a neutral charge of zero. But if there is an inbalance between protons and electrons, you get charged objects. The charge of each individual proton or electron is very small. So small you wouldn't even notice it. But usually there are many protons and electrons involved. When many protons or electrons are involved, we get large, noticeable charges, as in the following video:
Moving electrons will result in a flow of charge. Some materials allow electrons to move easily, and some materials don't, as in the following video:
The SI unit for charge is called a "Coulomb". 1 Coulomb is actually a pretty huge charge, since each individual electron has an electrical charge of -1.6 x 10-19 C. Protons have an equal and opposite electrical charge of +1.6 x 10-19 C. We don't break apart electrons in everyday life, so charge will always come in multiples of 1.6 x 10-19 C. If an object had two extra electrons, it would have a charge of -3.2 x 10-19 C. If an object had three extra protons, it would have a charge of +4.8 x 10-19 C. Watch the following video to see some examples of finding charges on objects:
There are two basic rules for dealing with charges:
1. Opposite charges attract each other, and like charges repel each other.
2. Charge is conserved.
After you have completed this part of the lesson, you can check the associated box on the main course page to mark it as complete 