Chapter 8 Ohm’s law describes the relationship of current, voltage and resistance Pages

8-1 Electric Potential Energy and Voltage Pages

Use an ammeter and a voltmeter to measure current and voltage in a circuit Ammeter A device used to measure current. Voltmeter A device used to measure the potential difference 3

Identify the volt (V) as the SI unit for electric potential Unit used to measure electric potential energy is the volt (V). Named after Alessandro Volta Measured by using a device called voltmeter 4

Define electric potential difference The amount of electric potential energy per one coulomb of charge The change in potential energy per coulomb of charge Measured in volts (V) Also known as voltage 5

Section 8.2 Electric Current Pages

3.07 Describe the flow of charge in an electric circuit 7

Define electric circuit A complete pathway that allows electrons to flow 8

Identify that electric potential is provided as the source and is “used” by the circuit elements 9

Describe the parts of an electric circuit. I.Source of electrical energy II.Electrical load III.Controls/switch IV.Conductor 10

3.08 Explain the importance of using precise language while studying the characteristics of electricity 11

Define electric current Electric Current  The amount of charge passing a given point in a conductor per second.  Measured in amperes (A)  Measured using 1. ammeter…strong current 2.galvanometer…weak current 12

Identify the ampere (A) as the SI unit for current Unit used to measure current … ampere Measured using Ammeter…strong current Galvanometer…weak current Name after Andre Marie Ampere Named after Luigi Galvani Ampere 13

3.09 Compare static electricity and current electricity Current Electricity  The continuous flow of charge in a complete circuit. Static Electricty Build-up of electric charges in an object. Jumps from one object to another 14

3.10 Organize information using a format appropriate to studying and describing current electricity Circuit Diagrams See symbols on page

Create circuit diagrams using appropriate circuit symbols I.Bulb II.Cell III.Battery IV.Wires V.Resistors VI.Ammeter VII.Voltmeter VIII.Open switch IX.Closed switch 16

continued… Draw and interpret electric circuit diagrams using electric symbols Activity - Page

8.3 Resistance and Ohm’s Law Pages

Define electrical resistance Electrical Resistance  Slows down the flow of electrons. (resistors)  Transforms electrical energy into light, heat, etc.  The ratio of the voltage to the current.  R = V I 19

Identify the ohm (Ω) as the SI unit for electrical resistance Electrical resistance is measured in ohm’s (Ω) Measured using ohmmeter Named after George Simon Ohm 20

List factors which affect the amount of resistance in a wire I.Length II.Diameter III.Type IV.Temperature 21

Ohm’s Law…animation

3.11 State a prediction and a hypothesis based on background information or an observed pattern of events Activity 8-3 B pages

3.12 Identify new questions and problems that arise from what was learned concerning voltage, current, and resistance Activity 8-3 B pages

State Ohm’s Law Ohm’s Law The mathematical relationship between voltage (V), current (I) and resistance (R) 25

Given voltage drop and current through a resistor, calculate its resistance Complete the practice problems Pages

Given voltage drop and resistance, calculate current through a resistor Complete the practice problems Pages

Given current through a resistor and its resistance, calculate the voltage drop Complete the practice problems Pages

Video…Ohms Law jE&feature=related jE&feature=related jX3dezzMg jX3dezzMg mk&feature=related mk&feature=related 29

3.13 Identify potential sources of error in ammeter and voltmeter readings Activity 8-3D Pages

3.14 Identify and suggest explanations for discrepancies in data collected using an ammeter and voltmeter Activity 8-3D Pages

3.15 Present graphically, using the line of best fit, data from investigation of voltage, current, and resistance Activity 8-3D Pages