Transcript Series and Parallel Circuits

Ingrid Munson & Meghan Campbell
Overview
Expectations
 Safety Considerations
 Prior Knowledge
 Game
 Lab
 Resources/Websites
 Exit Pass
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Grade 9 Physics
Characteristics of Electricity
Where does series and parallel
circuits fit into the unit?
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Throughout the unit, students gain an understanding of
basic electricity through a study of static and current
electricity.
Using a variety of instruments and tools, students develop
skills relating to the achievement chart.
They use their knowledge and understandings of the
relationships among current/electrical resistance/ potential
difference, and energy/power/time to solve simple
problems.
A culminating task could include the student applying their
knowledge to design and construct an electrical circuit
that performs a specific function.
During the unit they will evaluate social, economic, and
environmental costs and benefits associated with
electrical energy production and distribution in Canada.
Teaching Strategies
Today, our strategies include an
interactive game and an inquiry
investigation.
 Other teaching strategies include
website resources and other various
labs.
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Overall Expectations
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Design and conduct investigations into
electrical circuits found in everyday life
and into the quantitative relationships
among current, potential difference and
resistance.
Specific Expectations
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Describe the potential difference and current
characteristics in a series and a parallel
circuit;
Compare the electrical resistance of a series
and a parallel connection of identical resistors
to that of a single resistor
Demonstrate the skills required to plan
and conduct an inquiry into electricity,
using instruments, tools, and apparatus
safely, accurately, and effectively (e.g.,
use an ammeter and a voltmeter to
measure current and potential difference
in a circuit);
Goals of Lesson
Construct circuits and review prior
knowledge of series and parallel circuits
 Learn how to use ammeters and
voltmeters safely to make various
readings in different types of circuits
using light bulbs
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Safety
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Students are to be instructed in a safe and proper
operation of electrical equipment, especially equipment
involving voltages over 24 V (individual human tolerance
varies greatly);
Only CSA approved electrical equipment should be used;
Equipment should be checked to ensure connections are
tight and that there are no damaged or loose wires;
All electrical circuitry must be checked by the teacher
before the switch is closed where there is the possibility of
harm to students or damage to electrical equipment;
Students should be warned that dry cells may explode if
shorted out (short circuited);
Safety
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Wires which short circuit dry cells become
extremely hot and may cause burns when
touched, or fires if in contact with flammables.
The STAO web site at
http://www.stao.org/safety.htm has information
on safety publications, articles from Crucible
and links to other safety sites.
The teacher reinforces safety cautions noted
by students from their earlier years. Stress
should be on personal safety and the
appropriate use of equipment.
Prior Knowledge
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Students have some background knowledge of
electricity from their Grade 6 Science and
Technology program. They are familiar with terms
such as load, source, switch, conductor, insulator
and parallel and series circuit.
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Diagnosis of prior learning should continue
throughout the content of this unit. Students have
developed inquiry skills - both research and
experimentation - in previous units, and
also have gained experience in several different
modes of communication (e.g., oral presentation,
several forms of written reports, demonstration using
concrete materials, diagrams, use of models, etc.).
Circuit diagrams
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Minimum Three elements:
-Source of electricity (battery)
-Path or conductor on which electricity flows (wire)
-Electrical resistor (lamp) which is any device that requires electricity to
operate
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Pictorial way of showing circuits
This is the Ammeter symbol
This is the Voltmeter symbol.
This is the resistor symbol.
This is the switch symbol.
This is the battery symbol.
Series Circuit
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Closed electrical circuit that is
connected so that the current passes
through each circuit element in turn
without branching off.
Race Track
Parallel Circuits
•Have more than one path that the circuit can
follow and electrical energy therefore is not
shared.
•Each electrical device can be on or off within
the circuit.
Parallel Circuits
Cars have many pathways to travel, one might be a five lane freeway,
while another is a two lane street. Eventually all cars must return to the
service station for more energy.
Game
http://www.planetscience.com/sciteach/index.html?page=/unde
r11s/playground/playground.html
Current Electricity Lab
Pre-lab talk
 See lab handout
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Debriefing
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http://physics.bu.edu/py106/notes/Circuits.html
http://www.allaboutcircuits.com/vol_1/chpt_5/1.
html
http://www.iit.edu/~s
http://www.ndted.org/EducationResources/HighSchool/Electr
icity/seriesparallelcircuits.htm mile/ph9113.html
http://www.bbc.co.uk/schools/gcsebitesize/phy
sics/electricity/circuitsandamme
http://www.autoshop101.com/trainmodules/ele
c_circuits/circ120.html tersrev3.shtml
Misconceptions/Challenges
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Depending on students prior knowledge from the grade 6
curriculum, students may be at different stages of their
learning with this concept
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Definitions will need to be reviewed to ensure scientific
language is used -terms such as parallel difference, Ohms,
load, source, series circuit, parallel circuit, current
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Basic rules of schematic circuit diagrams (rectangular in nature;
correct symbols for components)
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Students may confuse the difference between ammeter and
voltmeter in terms of what each measures
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It is difficult for the teacher to explain this concept when
students cannot actually see it for themselves. This is why
circuit diagrams are so useful.
Resources
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The following Internet sites contain
information from Ontario Hydro on
safety codes and the Ontario power
generation system:
http://www.esainspection.net/main.html
http://www.ontariopowergeneration.com
The site below lists energy information
for common appliances
http://energuide.nrcan.gc.ca/
Resources
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The same information is available in the
book EnerGuide, available from various
hydro offices.
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The Office of Energy Efficiency of Natural
Resources Canada c/o Canada
Communication Group, Ottawa, ON K1A
0S9 has publications such as Air
Conditioning Your Home; Household
Lighting; Comparing Heating Costs; How
Can Energy-efficient Appliances Save You
Money?
Follow Up
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Concepts to follow would include:
-resistance
-electrical energy production
-static electricity
-simple home circuits
Helpful Websites
http://www.csupomona.edu/~apfelzer/de
mos/resistor/ser-par/10-ser.html
 http://www.tryengineering.org/lessons/el
ecswitch.pdf
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Exit Pass
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Often the actual values of the current
and potential difference are not exactly
the same as the predicted theoretical
values. What are two assumptions that
are made when we make predictions
about these values?