Download Electric Circuits 2014- revised

S8P5 [details]
Students will recognize
characteristics of gravity,
electricity, and magnetism
as major kinds of forces acting
in nature.
Element: S8P5.b
Demonstrate the advantages and
disadvantages of series and parallel
circuits and how they transfer energy.
Element: S8P5.c
Investigate and explain that electric currents
and magnets can exert force on each other.
How does electricity
flow to make things
happen around the
house?
You and your
shoulder
partner should
complete the
Path Finders
Activity.
What did
your team
find out
about the
systems?
Which
systems
worked?
1. What are
similarities
of the
systems that
work?
2. What are
similarities
of the
systems that
don’t work?
3. Is electricity flowing
through the systems
that make the bulb
light? How do you
know?
4. Is electricity flowing
through the systems
that don’t make the
bulb light? How do
you know?
5. What do you think
are necessary
elements of all
complete circuits?
Conductors Materials that allow electric
charges to easily move through them.
Examples: Metals
Insulators Materials that do not allow
electric charge to easily move through them.
Examples: Nonmetals, glass
•Electric forces arise from the presence of
an unbalance in electric charge.
•Electric Current is the flow of electric charges.
•Electricity always flows from a negative pole
•(excess electrons) to a positive pole
•(deficient in electrons).
Next slide is not in your notes!
What makes the water flow in figure A?
Apply this answer to figure B using negative
charges instead of water.
Water pressure and voltage behave in
similar ways.
Compare and contrast
unbalanced forces that cause
motion to the unbalanced forces
that cause electric forces?
Compare and contrast unbalanced forces that
cause motion to the unbalanced forces that cause
electric forces?
Unbalanced forces are required to cause a
change in motion (acceleration or deceleration).
Unbalanced electric forces are required
to make electrons changes their motion and
move.
Both require an unbalance (in force or
electric charge) for something to happen.
What is the difference
between static electricity
and current electricity?
What is the difference between static electricity
and current electricity?
Static electricity is stationary or collects on
the surface of an object, whereas current
electricity is flowing very rapidly through a
conductor.
Flow of Electricity
a) The flow of electricity in current electricity has
electrical pressure or voltage. (Push or pull
from electric force)
b) Electric charges flow from an area of high
voltage to an area of low voltage. See point
#3 under Current Electricity
c) Electricity can only flow when there is a closed
pathway for the charge to flow through
What makes the water flow in figure A?
Apply this answer to figure B using negative
charges instead of water.
Water pressure and voltage behave in
similar ways.
How is the flow of electricity
similar to the movement of
thermal energy?
How is the flow of electricity similar to the
movement of thermal energy?
Thermal energy flow from high concentration
(warm) to low concentration (cool) until
equilibrium is reached. Electricity flows from
high concentration (extra negative electrons)
to areas of low concentration (deficient of
electrons = positive area). Both flow from
“high to low”.
Electric Circuits
How is the flow of
electricity similar to the
flow of water through a
pipe?
Electric Circuits
How is the flow of electricity similar to the flow
of water through a pipe?
Both require a closed path or pipe.
Water pressure and voltage are similar because
the water or electricity flow from high pressure
to low pressure
Circuit uninterrupted
pathway or loop through
which electricity can flow
(usually wire pathway)
Electric Current (I) Rate at
which charges pass a
given point; measured in
amperes or amps (A)
Voltage (V) Potential
difference between two
points in a circuit;
measured in volts (V)
The pressure of the water flowing
through the pipes on the last slide
compare to the voltage (electric
potential) flowing through the wires
of the circuit. The unit used to
measure voltage is volts (V).
Circuit Terminology
Resistance( R) opposition to the amount of
current in a wire "electric friction";
measured in ohms(Ω) ; depends on:
a) Type of material
b) Thickness and length of wire
c) Temperature
What is electrical resistance?
Resistance (R)is the opposition to the flow
of an electric current, causing the electrical
energy to be converted to thermal energy or
light.
The metal which makes up a light
bulb filament or stovetop eye has
a high electrical resistance.
This causes light and heat to be
given off.
The unit for measuring resistance is the
ohm (Ω).
- charges always
flow in the same direction
- charges
continually shift from flowing in one
direction to flowing in the reverse
direction
Cell or Battery - device produces electric
current by converting chemical or radiant
energy into electrical energy
Thermocouple - device produces electric
current by converting thermal energy into
electrical energy
Photocells - device produces electric current
by converting light energy into electrical
energy
Energy Source - to push a charge through
the circuit.
Wires - transport the electric current
Load - changes electrical energy into another
form of energy; offer resistance to electric
current Examples: light bulbs turn electric
current into light and heat
Switch - device used to control
the flow in a circuit
Open switch - prevents the flow;
pathway has a break in it
Closed switch - completed pathways so
electricity can flow
All parts are connected in a single loop
 Only one pathway for electric charges
to follow
 Light glows with same lower
brightness as lights are added

 Resistance goes up and current drops
(dimmer bulbs)
 All loads (lights) turn on at the same time
 A break anywhere in the circuit causes all
lights to go out
Uses: burglar alarm system
 Parts are joined in branches - more
than one pathway for the electricity
to flow
 Potential difference (voltage) across
each part is the same
 Different branches can have
different currents
a. All lights glow with the same brightness
regardless of how many lights are added
b. If one light goes out, all remaining lights
remain on
c. can use one device (load) at the time
d.Uses: Electric outlets in a home
