Objective: MCAS review- Electricity Homework: Go to bed early Eat a healthy breakfast

Take out MCAS O.R. question Compare to other students’ work What would you rate each? What would you have scored?

Scoring Guide - Score Point 4Scoring Guide - Score Point 3Scoring Guide - Score Point 2Scoring Guide - Score Point 1Scoring Guide - Score Point 0

5 Main Topics of Electricity on MCAS  Circuits, Circuit diagrams, series vs. parallel  Ohm’s Law and Electric Power  Static Electricity: Induction and Contact  Coulomb's Law  Electromagnetism

circuit diagrams In circuit diagrams components are represented by the following symbols; battery Switch (open) lamp motorammetervoltmeterresistor Switch (closed) Some diagrams use the resistor symbol as a symbol for a lamp or light (since a light bulb is in fact a resistor!) wire

Electrical Circuit  A circuit is made up of a series of components all connected together and hooked up to a power source (such a a battery)  Any openings in a circuit and the circuit will stop working! (open switch)  Conductors like metal allow electricity to flow, but insulators (such as wood, plastic, rubber) stop flow of electricity.

The components are connected end-to-end, one after the other. They make a simple loop for the current to flow round. SERIES CIRCUITS If one bulb ‘blows’ it breaks the whole circuit and all the bulbs go out. Voltage shared, current same

PARALLEL CIRCUITS The current has a choice of routes. The components are connected side by side. If one bulb ‘blows’ there is still be a complete circuit to the other bulb so it stays alight. Voltage same, current shared.

Ohms Law Table

MCAS formula sheet only gives one Ohm’s Law formula:  V = IR So, set up triangle to solve for rest: Also do same for Power: P = VI V P VI

Bringing Charges Together Attract Repel

Charge by Induction: -no contact -no electron transfer -charged by “influence” Charge by Contact: -contact by items -electron transfer -charged by gaining or losing electrons Contact Charging by contact vs. charging by induction.

Coulomb’s Law More charge = more force (multiplying together) More distance = a lot less force (dividing by square of #)

When current flows through a wire you get a electromagnet  3 things make magnet stronger: - More current - More loops - Metal core