1. Methods of Charging

2. Charging Conductors by Contact
A negative rod touches a neutral metal sphere.
The sphere becomes negative due to a transfer of electrons.

4. Tip
The object becomes the same charge as whatever touched it.

5. Charging Insulators by Friction
When insulators are rubbed together, one gives up electrons to become positively charged while the other accepts the electrons and becomes negatively charged.

6. Grounding When a charged object becomes neutral as a result of
gaining or losing electrons via a connection to another
large object like the Earth.

7. Induction
This is a 2 step process: 1st – A neutral object becomes polarized. 2nd – The neutral object is grounded causing the object to become charged.

8. Example 1: using a negative rod

9. The ground is then removed while the rod is near.

10. now a

11. Example 2: using a positive rod
1st – the neutral sphere becomes polarized
2nd – the neutral sphere becomes grounded
Electrons enter the sphere since the ground sees nothing but positive charges and wants to make the sphere neutral.
The final charge of the sphere is negative.

12. Tip
The once neutral object becomes the opposite charge of the charged object (rod) that polarized it.