Download Sc9 - D 1.2 (teacher notes)

Learning outcomes:
1 I can distinguish between amps and volts.
2 I can identify a circuit.
1.2 – Current Electricity
Current Electricity
Static electricity = motionless….no movement.
Current electricity = has motion, needs a flow of electricity. This steady flow of
charged particles is called electrical current. This flow of particles is emitted by batteries,
electricity, etc…
Amperes (How fast it moves) : The RATE at
which an electrical current flows is measured in
AMPERES (A).
 This flow varies to a bit to a lot.


To allow flow rate, you need to use CONDUCTORS, where particles can easily
move.
To measure amps, you use an Amperemeter.
Circuits: A pathway that allows the flow of electricity.


Most use wires as conductors.
A circuit consists of a conductor, an energy source, a load and often a switch (to
control the flow.)
Electrical Energy and Voltage (How much energy a charge can possibly
be used): Voltage is a measure of how much energy each particle carries.

This is also called “potential difference’.
That means the higher the voltage, the greater the potential it has to use
big amounts of energy.





The energy delivered by a flow of
charged particles is equal to the
voltage, times the total charge of
the electrons.
Voltage units are volts (V)
You use a VOLTMETER to
measure volts.
When using the VOLTMETER,
always put the RED with the +, and
the BLACK with the -. (Same as
booster cables.)
You can connect the voltmeter to
the computer.
Graph analysis
1. What is the subject?
2. What conclusion can be made with this graph?
3. What can be inferred from this graph?
Allez au site (http://phet.colorado.edu/en/simulations/category/new).
On va commencez avec La construction des circuits (Circuit Construction Kit-DC only) simulation, found
under Physics -> Electricity, Magnets and Circuits.
Part I: Build a simple circuit (6 minutes)
1.
2.
3.
4.
Click schematic on the right side.
Use 3 minutes to explore.
Push on reset.
Build a circuit using the following: wire, two batteries, a light, an ammeter
and a switch .
a. Make sure the ammeter is connected to both sides of the wire. See
image above.
5. Draw a diagram of your circuit
Part 2 : Measuring current
Question : Does current vary
depending on the location of the
circuit?
1.
Use your previous circuit
2.
Measure your current and add the values in the chart below
i)
ii)
iii)
iv)
After the battery (POISITION A),
After the switch (POSITION B)
After the light (POISITION C)
Before entering the battery (POSITION D)
3.
Current
Ammeter position
4.
Analysis
i) Compare the current before and
after the battery? What are your
observations?______________
Electrical current
Open switch
Closed switch
A
B
C
________________________
D
________________________
________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______
ii)
Compare current before and after the light? What do you observe?
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
_____________
iii) How does opening the switch afect current?
____________________________________________________
______________________________________________________________
_______
iv) What are the conditions required to have current in a cirucuit?
______________________________________________________________
______________________________________________________________
______________
Part III : Measuring Voltage
Question : Is the voltage (potential difference) the same at different locations in
the circuit?
Voltage
Position of voltmeter
A
B
C
D
E
F
Voltage (V)
Without lights
1.
Use you first circuit however add a
second light after the first one.
2.
Measure voltage and add your results to the chart.
i)
ii)
iii)
iv)
v)
vi)
Around the battery (POISITION A),
Around the switch (POSITION B)
Around the light (POISITION C)
Around the other light (POISITION D)
Around both lights (POSITION E)
Between the second light and the + side of the battery ( POSITION F)
3.
Take off both lights and measure voltage.
4.
Analyse
i)
What part of the circuit does current come
from?____________________________
ii)
What is using the current?______________________________
iii)
Compare voltage in position A and E. _______et ________
iv)
Compare the created and used voltage of the circuit. ____________ et
________________
v)
Is the voltage the same between either light compared to the entire circuit?
____________________________________________________________________
_______
vi)
When you take off the lights from the circuit, does the voltage from position E
vary? If yes, explain why?
_____________________________________________________________________
______________________________________________________________________
________________
Vocabulary – Static electricity, current electricity, amperes, ammeter, conductor, circuit,
energy source, load, voltage, voltmeter, amps (A), volts (V)
Answer questions from page 283 - #1, 2, 3, 4, 5, 6, 8