1. Electricity and Magnetism
Physical Science Goal 4
Electricity and Magnetism

2. Static Electricity Static Electricity—electricity that is not moving.
Basic Law of Electrostatics
Like charges repel, opposite charges attract!!
How do objects become “charged”????
Objects become charged by gaining or losing electrons!! Protons will not move!!!

3. 3 ways to charge an object:
Conduction—direct contact
No contact, no conduction
Friction—Rubbing together
Induction—Rearrangement of charge of a neutral object caused by a nearby charged object!

4. Current Electricity
Voltage will determine whether electricity will or will not flow!!!!
Resistance determines how much current flows!!
Low resistance, high current
High resistance, low current

5. Electricity Symbols and Units
Quantity
Symbol in Equation
Unit
Symbol Unit
Current I
Amperes A
Resistance R
Ohms W
Voltage V
Volts
Power P
Watts

6. Electricity Equations

7. 2 Types of Electric Circuits:
Series Circuit
Parallel Circuit
Current has only one path to take.
All of the current will travel through each device.
“Cheap” Christmas tree lights.
Current has more than one path to take.
All of the current will not travel through each device.
“Expensive” Christmas tree lights.

8. Hence, the “Cheap lights”!
Series Circuit:
In a series circuit, if one of the lights goes out, what happens to the remaining light(s)?
Hence, the “Cheap lights”!

9. Hence, the “Expensive lights!!
Parallel Circuit
In a parallel circuit, if one light goes out, what happens to the remaining lights?
Hence, the “Expensive lights!!

10. Discuss Current through each of the lightbulbs in the pictures below:

11. Magnetism Like Poles repel, opposite Poles attract!!
Magnetic Field Lines always move out of the north pole and into the south pole!!!
Magnets are strongest at the poles!!
If you break a bar magnet in half, you get 2 bar magnets both with a north and a south pole!!
Lines of Attraction
Lines of Repulsion

12. Magnetic Domains
In a permanent magnet, the “Domains” are aligned. In a normal piece of metal, the domains are not aligned!!
You can only make a magnet from Iron, cobalt and Nickel(Iron Triad)

13. Electromagnetism
Oersted—If a current moves through a wire, there will be a magnetic field produced around the wire.
Faraday—If you move a wire through a magnetic field, or a magnetic field through a wire, there will be a current induced in the wire!!

14. Electromagnet
A temporary magnet. Will quit working when the current is turned off.
3 requirements:
Iron Core
Turns of Wire(conductor)
Current

15. 2 ways to strengthen Electromagnet:
Increase the current
Increase the # of turns of wire
Motor vs. Generator
Motor—converts electrical energy into mechanical energy(something turns)
Generator—converts mechanical energy into electrical energy(you get electricity)