1. Physics
Electrostatics

2. Four Fundamental Forces
Gravity
Cosmic and Macroscale
Electromagnetic
Macroscale and
Microscale
Weak
Strong
Subatomic
Nuclear

3. Electromagnetic Force
Force of attraction or repulsion due to an imbalance of electric charge
Opposite Charges Attract
Like Charges Repel

4. Electric Charge
Atoms are composed of positive protons, neutral neutrons, and negative electrons
Neutral atoms
have equal numbers of
positive protons and negative electrons

5. Electric Charge
Protons and neutrons are locked in the nucleus and can not move freely
Electrons are found outside the nucleus in energy levels and are free to move
A positive or negative electric charge results from objects gaining or losing electrons

6. Conservation of Charge
When electrons are transferred from one object to another, no electrons are created or destroyed.

7. Charging By Friction Results from rubbing objects together
Called triboelectric charging
Friction strips electrons from atoms of one object and deposits them on another object

8. Conduction Charging by contact
Charging a neutral object by making contact with a charged object
The resulting charge is always the same at the original charge.
Requires a conductor

9. Conduction
When a negatively charged object touches a neutral object, the repulsive force between the electrons pushes the mobile electrons off of the negative object and onto the neutral object.
Thus, the original negative charge is spread over both objects.
Objects are separated after initial touch
- Charged object touches neutral object
Both objects have a negative charge
Some electrons move onto sphere
Notice the negative charge on the original object is reduced because
some electrons moved to the sphere

10. Conduction
When a positively charged object touches a neutral object, the force of attraction pulls mobile electrons off of the neutral object onto the positively charged object
Results in both objects obtaining a positive charge
Objects are separated after initial touch
+ Charged object touches neutral object
Some electrons move to positive object
Both objects have a positive charge
Notice the positive charge on the original object is reduced because
some electrons moved onto the object from the sphere

11. Induction
Charging of a neutral object by bringing a charged object near (but not touching) it.
Includes two processes: Polarization and Grounding
Results in two oppositely charged objects

12. Induction
A negatively charged balloon is brought near a neutral sphere
The negatively charges repel the electrons of the sphere pushing them to the opposite side of the sphere.
Polarization – object with two oppositely charged ends

13. Induction
The negative charged electrons on the sphere are removed by touching it with a finger (or other object)
Grounding – connecting a charged object to Earth to allow electrons to travel to or from the object depending on the situation

14. Induction
The finger (or grounding object) is removed and the balloon and sphere are separated
Notice the positive charge is
equal to the negative charge
on the original balloon (there
Is no reduction of charge)