It is expected that students will explain how electric current results from separation of charge and the movement of electrons.
Students who have fully met the prescribed learning outcome are able to:
Distinguish between
- potential and kinetic energy
- static electricity and electric current
- conventional current and electron flow
Relate the charge on electrons to electron flow in a circuit (i.e.,
from negative to positive)
Define current in terms of the amount of electric charge that
passes a point in a given time interval
photo: lucky-frank@morguefile
RESOURCE
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PLANNING FOR ASSESSMENT /ASSESSMENT STRATEGIES
Review with students the definitions of force,
types of energy, and static charge. Ask students
“When an object has a static charge, where are
the charges positioned?” Discuss repulsion of
like charges. “What if you touch the charged
object or give the charge a path (wire) to
ground?” Discuss grounding ( more).
• Assess whether students’ answers to questions
show that they understand the difference between
kinetic and potential energy with respect to static
electric charges and electric current.
• Have students draw and label diagrams that
illustrate forces, energy, and charge (static and
moving). Verify accuracy.
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Explain that electrons flow as a result of
attractive and repulsive forces acting on them.
Briefly explain how voltage is a description of
the amount of energy of a charge (i.e., due to
the separation of charges). Ask, “How can
energy be given to a charge?” Demonstrate
and explain some different types of power
supplies, energy converters, and generators.
Then show students the symbols used in
circuit diagrams and how to measure voltage
of cells using a voltmeter.
Assess students’ understanding of energy
generation by considering how many different
ways of giving energy to a charge they can
identify (e.g., rubbing two materials, using a
chemical cell, a generator, thermocouples, piezoelectric
device, photo-electric cell).
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Have students use a voltmeter to measure the Have students draw circuit diagrams to represent .............................................................................................................................
voltage of cells connected in series and in
parallel.
their work with cells and voltmeters. Assess the
extent to which their diagrams
- show the correct arrangement of cells in series
and parallel
- use proper symbols for devices used
- include proper voltmeter readings (with
units)
- include conclusions about the differences in
voltage when cells are connected in series and
parallel
flow (the amount of electric charge that passes
a point in a given time interval). Explain that
historically (before the time of Coulomb),
people believed that positive charges flowed
through a wire (conventional current).
Compare this with the modern understanding
(flow of electrons).
• Instruct students in the correct use of an
ammeter.
Have students use an ammeter (lab) to measure total
current in a series circuit vs. a parallel circuit as
more devices (resistors, light bulbs) are added
(voltage is kept constant). Have them record
observations using circuit diagrams and draw
conclusions. Assess their work by considering
whether they have
- properly connected the ammeter
- obtained reasonable measurements
- drawn symbols correctly
- recognized how current changes when
devices are added in both series circuits
(current decreases) and parallel circuits
(current increases)
Consider using the Lab Report Performance Task
Definition and the Lab Report Scoring Rubric
provided at the end of the Classroom Model for
this grade.
