chapter 8 ohm’s law describes the relationship of current, voltage and resistance pages 248-283 1
TRANSCRIPT
Chapter 8 Ohm’s law describes the relationship of current, voltage and
resistance
Pages 248-283
1
8-1 Electric Potential Energy and Voltage
Pages 250-259
2
3.06.1 Use an ammeter and a voltmeter to measure current and voltage in a circuitAmmeter• A device used to
measure current.
Voltmeter• A device used to measure
the potential difference
3
3.06.2 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
3.06.1 Define electric potential differenceThe amount of electric potential energy
per one coulomb of chargeThe change in potential energy per
coulomb of chargeMeasured in volts (V)Also known as voltage
5
Section 8.2 Electric Current
Pages 260-269
6
3.07 Describe the flow of charge in an electric circuit
7
3.07.1 Define electric circuit
• A complete pathway that allows electrons to flow
8
3.07.2 Identify that electric potential is provided as the source and is “used” by the circuit elements
9
3.07.3 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
3.08.1 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 current2. galvanometer…weak current
12
3.08.2 Identify the ampere (A) as the SI unit for currentUnit used to measure current … ampereMeasured using
Ammeter…strong currentGalvanometer…weak current
Name after Andre Marie AmpereNamed after Luigi Galvani
Ampere 13
3.09 Compare static electricity and current electricityCurrent ElectricityThe continuous flow
of charge in a complete circuit.
Static ElectrictyBuild-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 262.
15
3.10.1 Create circuit diagrams using appropriate circuit symbolsI. BulbII. CellIII. BatteryIV. WiresV. ResistorsVI. AmmeterVII.VoltmeterVIII.Open switchIX. Closed switch 16
3.10.1 continued…
• Draw and interpret electric circuit diagrams using electric symbols
• Activity - Page 263
17
8.3 Resistance and Ohm’s Law
Pages 270-283
18
3.10.2 Define electrical resistance
Electrical ResistanceSlows 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
3.10.3 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 Ohm20
3.10.4 List factors which affect the amount of resistance in a wireI. LengthII. DiameterIII. TypeIV. Temperature
21
Ohm’s Law…animation
• http://www.physicslessons.com/phe/ohmslaw.htm
• http://www.physicslessons.com/exp41.htm
22
3.11 State a prediction and a hypothesis based on background information or an observed pattern of events
• Activity 8-3 B pages 275
23
3.12 Identify new questions and problems that arise from what was learned concerning voltage, current, and resistance
• Activity 8-3 B pages 275
24
3.12.1 State Ohm’s Law
Ohm’s LawThe mathematical relationship between voltage (V), current (I) and resistance (R)
25
3.12.2 Given voltage drop and current through a resistor, calculate its resistance
Complete the practice problems Pages 273-275
26
3.12.3 Given voltage drop and resistance, calculate current through a resistor
Complete the practice problemsPages 273-275
27
3.12.4 Given current through a resistor and its resistance, calculate the voltage drop
Complete the practice problems Pages 273-275
28
Video…Ohms Law
• http://www.youtube.com/watch?v=JRp_iSaVRjE&feature=related
• http://www.youtube.com/watch?v=_-jX3dezzMg
• http://www.youtube.com/watch?v=8utldTdAJmk&feature=related
29
3.13 Identify potential sources of error in ammeter and voltmeter readings
Activity 8-3D Pages 278-279
30
3.14 Identify and suggest explanations for discrepancies in data collected using an ammeter and voltmeter
• Activity 8-3D Pages 278-279
31
3.15 Present graphically, using the line of best fit, data from investigation of voltage, current, and resistance
• Activity 8-3D Pages 278-279
32