October 29, 2012 WHEN FINISHED WITH BELLRINGERS: Pick up notes from back & lab pkt from side What are 2 things you know about electricity? Why are metals often used in circuits?

October 30, 2012 Describe how lightning works.

Goal To create working circuits To define electricity and circuit

Q: What is electricity? Electricity is the movement of electrons through something (“medium”) Electrons move for 2 reasons They are attracted to… PROTONS! (Thanks Paula Abdul!) main reason for electricity! They are “hit” by another electron and bounce out of the way.

Q: What is electricity? Electricity is similar to water moving in a hose.

Q: What is a circuit? A complete pathway for electrons to travel In a complete circuit, electrons must be able to travel back to their starting point! Has 3 main parts: Source of power/electrons (ie. battery) Medium for electrons to travel (ie. wire and other conductors) Something for electrons to do work on (ie. light bulb)

Can have other parts Resistor- designed to slow down the flow of electrons. Made of material that isn’t quite considered to be a conductor, but isn’t an insulator either…. Different materials allow circuits to have different resistances. Switch- allows you to disconnect the circuit when you want electrons to stop flowing and reconnect when you want electrons to resume flowing

Q: What is a circuit? Circuits are often drawn as a diagram using the symbols given below:

Practice Draw a circuit with an open switch, motor, triple cell battery, and one resistor.

Q: What are some “types” of circuits? Complete vs. Incomplete Pathway Closed circuit. Just means the circuit is complete and electricity CAN travel thru it. Open Circuit Means the circuit is incomplete and electricity CANNOT travel thru it. Usually, this occurs when you move a switch to the off position.

Organization of Pathway Series Circuit All the objects that work is done on (ie. light bulb) are in a straight path. In a series circuit, you can travel from one object to the next only ONE way. There are no options! Parallel Circuit Objects that work is done on (ie. light bulb) are NOT in straight path. In a parallel circuit, you have options as to how you can travel from one object to the next!

Q: What is an electrical current? Electrons (charges) in motion Comparison to water hose: This is the moving water Two Main Types of Current Alternating (AC): electrons constantly change directions, like an outlet Direct (DC): electrons move only in one direction, like a battery

Homework Part 1 & 2 of packet