Electricity and Magnetism Physical Science Goal 4 Electricity and Magnetism

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 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!

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

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

Electricity Equations

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.

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”!

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!!

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

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

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)

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!!

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

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)