1. Electricity and Electrical Charges
What is electricity?
All the phenomena caused by positive and negative charges.
Where do these charges come from?

2. Definitions
Static Charge – is a build up of electricity that is waiting to be expelled. Thus, the person/object that is charged is at rest. Hence, a static charge.
Discharge – occurs once you bring a charged object near another non charged object, the amount of electricity is released.
Electrostatic – is the study of static electric charges

3. Electrons: Nucleus: Located outside nucleus
Contains protons (+) & neutrons (no charge)
Overall positive charge (+)
Contains nearly all mass (dense)
Electrons:
Located outside nucleus
Easily moved, lost or gained
Negative charge (-)

4. Electrical Charges: - All matter has electrical charges
There are two types of charges:
Positive
Negative + -

5. Negatively charged objects: contain more electrons (-) than protons (+).
Positively charged objects: contain fewer electrons (-) than protons (+).
Only negatively charged electrons can move from one object to another and if you have an equal number of protons and electrons, the object is neutral.

6. Law of Charges Attraction Repulsion Opposite charges
Law of Electrical Charge – like charges repel and unlike charges attract.
There are 2 forces between charged objects:
Attraction
Repulsion
Opposite charges
“Opposites Attract”
Same charges
“Like repel”
Law of Charges

7. - + Ex #1 A B A POSITIVE Opposites Attract!
Sphere A is negatively charged.
When placed beside sphere B, they attract.
What is the charge on B?
POSITIVE
Opposites
Attract! A B A - +

8. - + + + - + Ex #2 Attract A C A B B C
Three charged spheres are suspended next to each other.
If sphere A is negatively charged, what will happen when sphere A & C are suspended beside each other?
Attract A C A B B C - + + + - +

9. + + + - - + Ex #3 A B B C C D Repel
Four charged spheres are suspended next to each other.
What will happen if A & D were suspended next to each other?
Repel A B B C C D + + + - - +

10. What would happen if “B” & “C” were brought together?
You have three charged objects – A, B & C in a lab. You record the following results:
Ex #4
Test
Observation
Bring “A” near “B”
They repel
Bring “A” near “C”
They attract + + + - + -
What would happen if “B” & “C” were brought together?
They would attract!!!

11. Assignment
Page 278 1, 2, 4, 5, 7, 9, 12, 13 (a)