Transcript (ELECTRICITY).

Electricity & Types of Circuits- Page 4
• 7.4- TSW DESCRIBE DIFFERENT FORMS OF
ENERGY (ELECTRICITY).
• Electricity- the flow of electrons between
points having different electrical charges
• Direction of Electron Flow- Out of negative end,
into positive end
– In order for electrons to flow, they need a
source (like a battery), a path (a conductor),
and this path must form a complete circuit (like
a loop)
6.14- TSW DEMONSTRATE THE PROPERTIES THAT CAN BE
USED TO IDENTIFY MATTER: CONDUCTIVITY.
• Conductor- Material through which electrons can
easily flow; conduct electricity well
– Most metals are good conductors ex: copper, gold,
silver
– Current- the flow of electricity in a conductor
• Insulator- Material in which electrons are slowed
down; keep electricity from moving
– Insulators are common: most plastics, wood, glass,
leather, etc.
– Resistance- The opposition to the movement of electric
charges flowing through a material.
• An electric current will always flow the path of least
resistance
• Circuit- a complete path consisting of electronic elements
(conductors, resistors, etc.) through which electric
current moves
• Switch- A device used to open and close an electric
circuit
• Simple Circuit- A circuit containing the minimum things
needed to have a functioning electric circuit. A simple
circuit requires three (3) things:
Types of Circuits
1. A source of electricity or voltage (ex. battery or electrical outlet)
2. A conductive path which would allow for the movement of
charges. (ex. wire)
3. An electrical resistance (resistor), or load; loosely defined as any
object that uses electricity to do work (ex. a light bulb, electric
motor, heater, speaker, etc.)
Broken Simple Circuit  = No light
Types of Circuits
• Series Circuit- A simple loop with all loads
connected in a line
– Bulbs share the voltage of the battery
• Ex. If the battery is 9V, and there are two bulbs, each
bulb gets 4.5 volts
– If one light is disconnected, then the other(s)
loses power.
Types of Circuits
• Parallel Circuit- Two loops, both connected
to the battery, each with its own load
– Bulbs have the full voltage of the battery.
– Bulbs in the parallel circuit will be brighter than
those in the series circuit.
– If one light is disconnected, then the other(s)
remains powered.
Packet 15, RIGHT Page 6 – EXTRA CREDIT
7.16- TSW DESCRIBE HOW ELECTRICAL CIRCUITS TRANSFER ENERGY
TO PRODUCE HEAT, LIGHT, SOUND, AND CHEMICAL CHANGES.
Packet 16, Page 4
• Static electricity- build up of
charges on an object
– Rub two materials together
– Electrons pulled off one surface,
relocated on other surface
• Lose electrons  + charge; gain
electrons  - charge
• +/- attract; -/- repel; +/+ repel
• Static discharge- spark/shock; the
loss of static electricity as electric
charges move off an object in an
attempt to become neutrally
charged
Track A:
Circular Go-Kart track vs.
Series electrical circuit
• If you add another car to the Go-Kart track, what do you
think will happen to the speed of the other cars?
– They will slow down because they don’t have any
where else to go.
• What will happen to the green car if the orange car breaks
down on the track?
– The green car will have to stop, because there is no
way for it to go around.
Track B:
Figure 8 Go-Kart track vs.
Parallel electrical circuit
• If you add another car to the track, what do you think will
happen to the speed of the other cars?
– They will stay at the same speed because they have
more options of where they can go.
• What will happen to the green car if the orange car breaks
down on the track?
– The green car will keep going, because there are other
ways that it can keep driving around.
Electricity/Magnetism Videos
• How Electricity is Created from Magnets
– 9.15- Start 3.50 end 6.18
• Electricity_and_Magnetism__Current_Elect
ricity 16.58
– Start .36 end 7.29
Bellwork: Tuesday 5/29/2012
Match the word
to
its
definition
• the movement of electrons
1. Current
2. Electricity
3. Circuit
between points having different
electrical charges
• a complete path consisting of
electronic elements (conductors,
resistors, etc.) through which
electric current moves
• the flow of electricity in a
conductor
• School House ROCK!
Electricity/Magnetism Videos
• How Electricity is Created from Magnets
– 9.15- Start 3.50 end 6.18
• Electricity_and_Magnetism__Current_Elect
ricity 16.58
– Start .36 end 7.29
• Electric current flow is necessary for electric
shock, but only happens from places of voltage
differences
– both the bird's feet are at the same voltage
• Most birds perch on electrical wires perfectly
safely—but there are some dangers.
• In particular, large birds such as eagles have wingspans
wide enough that they occasionally brush two parallel
wires with their wingtips, which completes the electrical
circuit and allows electricity to run through the bird's
body, killing them. 
– This is a serious problem in certain desert areas where the birds
use the electrical poles for nesting, due to limited other options.
Circuit Review:
• Series circuit- An
electric circuit with one
path for the current to
take.
• Parallel circuit- An
electric circuit with
several paths for the
current to take.
• Flow of electrons  In
an electrical circuit,
electricity flows from
the negative end to the
positive end
Symbols- Circuit diagrams- Page 5
If Circuits A and C are
the same, and
Circuits B and E are
the same, what is the
symbol for: 1). wire,
2). light bulb, 3).
battery, 4). switch?
Circuit Diagram Symbols- Page 5
• 7.17- TSW IDENTIFY AND
SKETCH THE COMPONENTS
OF AN ELECTRICAL CIRCUIT.
• Wires are shown as
straight lines between the
different circuit symbols
• Cell vs. Battery
– Single battery = cell
– Two or more cells connected
together = battery
Circuit Diagrams
• Use circuit symbols instead of drawing each
component in the circuit.
• Always make the wires straight lines
– don't be tempted to make them wiggly
– the whole point is to make it easier to see what is
connected to what
• Below: A simple circuit– 1 cell, 1 light, 2 wires.
Draw the circuit diagram (using symbols), include
arrows to show the direction of electron flow.
TIP: Draw the
circuit symbols
first, and then add
all the wires.
Series Circuit- 1 cell, 3 bulbs, 5
wires, 1 switch
Practice with Circuits
DO NOT unscrew the light bulbs to
make this work!!
• With your group, create a series circuit and
a parallel circuit.
• Challenge: Try to get a light bulb to light
using only:
– 1 wire
– 1 bulb
– 1 battery
• Homework: Pg. 6 left side “Will these
Circuits work?”
Bellwork: Wednesday 5/30/2012
1. In a series circuit with three
bulbs, adding another bulb
will
•
•
•
•
make the nearest bulb brighter
make some of the bulbs dimmer
make all the bulbs brighter
make all the bulbs dimmer
1. In a series circuit,
adding another bulb
will make all the bulbs
dimmer!
2. In a parallel circuit with
three bulbs,
•
•
•
•
the bulbs must all be located on
the same branch
there is only one path for the
current to take
current from each bulb has its
own path
the overall resistance
increases if a new branch is
added.
2. In a parallel circuit,
current from each
bulb has its own path!
Housekeeping
• Turn in:
– Quarter 4 OOPS Pass
• FINISHED Study guide DUE MONDAY
• Monday- Study Guide Review…
Jeopardy?
• NOW: Electricity!!
Electricity Lab- Page 7
7.15- TSW BUILD A SYSTEM THAT
GENERATES ELECTRICITY.
- Explain materials and how to use them
-Read through tasks
-Explain picking up of materials
-Draw the circuit, show electron flow, and
when the light is lit, raise your hand so you
can get signed off!