Transcript Aim: Electricity Do Now:

Aim: What is electric charge?
(Monday)
Do Now: What are 2 types of electric charge?
Homework: Read pgs 392 – 394 &
Study for Quiz
1. What is matter?
2. What is all
matter made
from?
• Anything that has
mass & volume
Examples:
Solids, Liquids, Gases
• Atoms
3. What are the
building
blocks of an
atom?
1. Protons,
2. Neutrons &
3. Electrons
4. Where are these 1. In the Nucleus
(center of atom)
subatomic
Protons &
particles located
Neutrons
in the atom?
2. Electrons move
around the
nucleus in energy
levels
(also called shells or
orbits)
5. What is the
electrical charge
on the subatomic
particles?
1. Protons =
Positive charge
or (+)
2. Electrons =
Negative charge
or (-)
3. Neutrons =
Neutral or No
Charge
The Structure of an Atom
6. What makes
atoms electrically
neutral?
(no charge)
# of protons
=
# of electrons
Example:
Hydrogen has
1 protons &
1 electrons
Therefore: + 1
-1
0
7. How would an
atom gain a
negative charge?
(-)
It must gain one
or more electrons
8. How would an
atom gain a
positive charge?
(+)
It must lose one or
more electrons
Hydrogen
Normally
Neutral
Gains an
Loses an
Electron = Neg. Electron = Pos.
Charge
Charge
+1
-1
+1
-2
+1
0
0
-1
+1
What part of the atom is gained or
lost?
• ONLY the Electrons
• Never Protons
9. What is the Law
of Electric
Charge?
1. A force of
attraction exists
between
oppositely
charged particles
(+) & (-)
2. Like charges
repel each other
(+) & (+) or
(-) & (-)
Law of Charges
Quiz (The Atom)
1. What type of charge do electrons have?
2. What would make an atom electrically
neutral?
3. Anything that has mass & volume is
known as _____________.
4. The nucleus of an atom contains both
____________ & ___________.
5. What type of charge do neutrons have?
Quiz (The Atom)
6. Do oppositely charged particles attract or
repel each other?
7. Protons have a _________ charge.
8. How does an atom gain a negative
charge?
9. What part of the atom is gained or lost?
10. How would an atom gain a positive
charge?
Aim: How can objects become charged? (Tuesday)
(3 Methods)
Do Now: Prepare for Quiz.
Homework: Read pgs 395 – 399 &
Study for Quiz
• Electrons are
1. How does a
either gained or
neutral object
removed
acquire an
electric charge?
2. What are 3 ways
to charge an
object?
1. Friction,
2. Conduction &
3. Induction
3. What is friction?
• The force that
opposes motion
4. What can cause
friction?
• Rubbing 2 objects
together
5. How can this
create a charge?
• Electrons are
removed from one
object & gained by
the other object
6. What happens to
a balloon when
you rub it against
a cloth?
a) The balloon gains
electrons
(negative charge)
b) The cloth loses
electrons
(positive charge)
7. What causes the
balloon to stick to
the wall?
1. The electrons in
the wall are
repelled by the
negative charges
on the balloon
2. The positive
charges in the
wall are attracted
to the balloon
Balloon & Cloth
8. How is an object
charged by
conduction?
a) Through direct contact
9. What materials
allow electrons to
flow freely?
Conductors
Example • Metals such as:
Silver, Copper,
Aluminum &
• The Earth
b) Electrons can flow
through one object to
another
10.What materials
do not allow
electrons to flow
freely?
Note:
Good conductors
& insulators of
ELECTRICITY
Insulators
Example –
rubber, glass,
wood, plastic, air
Good conductors
& insulators of
HEAT
11. How is an object a) Rearrangement of
charged by
electric charges
induction?
b) No Contact is necessary
Example:
The negatively charged
rubber rod causes the
meter stick to move
without touching it
12. How is induction a) Conduction
different from
involves Direct
conduction?
Contact
b) Induction – No
direct contact
Quiz (Charging)
1. What materials do not allow electrons to
flow freely (conductors or insulators)?
The next 3 answers pick: friction, conduction, or
induction
2. What method of charging occurs through
direct contact?
3. What type of charging occurs when the
charges on a neutral object are
rearranged (redistributed)?
4. What is the force that opposes motion?
Quiz (Charging)
5. Good conductors & insulators of
electricity are also good conductors &
insulators of __________.
6. What caused the rubber rod to become
negatively charged?
7. How can an object become charged
without direct contact?(friction, conduction,
induction)
8. What is an example of a good conductor?
Quiz (Charging)
9. What happened to the balloon when we
rubbed it against the rabbit’s fur?
10.What happened to the rabbit’s fur?
Bonus: What happened to the number of
protons on the balloon & rabbit’s fur?
Aim: What is lightning?
Do Now: Prepare for Quiz.
Homework: Study for Quiz
1. What
type of
charge is
shown in
the
pictures?
(Wednesday)
2. What causes
lightning?
1. Static Electricity
&
2. Electric
Discharge
3. What is static
electricity?
a) The buildup of
electric charges on
an object without
further movement
b) This is caused by
friction
4. What is electric a) The loss of static
electricity as
discharge?
electrons move off
an object
b) As electrons move
through the air:
• noise may be heard
• a spark of light can
be seen
• you may feel a shock
1. What causes the clouds to be charged?
2. What causes the ground to be
positively charged?
5. What can be used
a) A lightning rod
to protect a
building?
b) Made from:
Metal
c) Positioned:
Higher than the
building
6. What instrument
can be used to
detect an electric
charge?
An electroscope
7. How does an a) Normally, the metal
electroscope
leaves hang freely
work?
b) If a negatively charged
rod touches the metal
ball on top, electrons
move down both leaves
c) Like charges repel
each other, & the
leaves spread out
8. What happens if a) Electrons from
the electroscope
a positively
are attracted to
charged glass rod
the rod & flow up
touches the metal
into the rod
ball on the
b) Both leaves
electroscope?
become positively
charged
c) They repel &
spread out
Quiz (Static Electricity)
1. The loss of static electricity is known as
_____________.
2. An instrument used to detect electric
charge is known as ____________.
3. The build-up of electric charge without
further movement is known as _________.
4. What types of materials are lightning rods
made from?
5. Static electricity is caused by __________.
Aim: How is the flow of electricity created?
Do Now: Prepare for Quiz.
Homework: Read pgs 400 – 404 &
Study for Quiz
(Thursday)
1. What is the flow a) Electric Current
of electricity
b) Or the amount of
called?
charge that passes a
given point per unit
time
Recall Questions
• What are 2 types
of charges?
• Positive &
Negative
• What materials
allow electrons to
flow freely?
• Conductors
Examples?
• What materials
hold on tightly to
their electrons?
• Insulators
Examples?
2. What symbol
represents
“current”?
Capital letter:
3. What units are
used to measure
current?
The ampere or
amp
= the amt. of current
that flows past a
point per sec.
I
4. Within the wire,
a) Resistance, or
what opposes the
R
flow of electric
charge (current)? b) Resistance
depends upon:
 The material of
(This is like you
the wire
walking down the
hallway!)
 The thickness &
length of the wire
 Temperature
•
As the thickness of a wire increases, the
decrease
resistance will ___________.
•
As the length of a wire increases, the
resistance will _____________.
increase
•
As resistance increases, current ______.
decreases
•
If it is difficult for electric charge to flow
is higher
through a material, resistance _________.
•
What happens to resistance at very low
temperatures? decrease
5. What is the unit
for resistance?
6. How is resistance
necessary in a
light bulb?
the ohm or (Ω)
The metal filament
in the center offers
enough resistance
to the electric
current flowing
through it causing
LIGHT & HEAT
to be given off
7. What causes an
electric charge to
move?
a) WORK
Remember: Work =
Force X Distance
b) The amount of
work required to
move a charge
between 2 points
is the:
Electric Potential
Difference
8. What is the unit
of potential
difference?
a) The volt (V)
9. What are some
examples of
voltage?
1.
2.
3.
4.
b) The term Voltage is
often used for
potential difference
Batteries
Electric generators
Thermocouples
Photo cells
Batteries containing
Electrochemical Cells
A Thermocouple
produces electrical
energy from heat
energy
(temperature
differences)
Aim: 1. How are current, resistance,
(Friday)
voltage related to each other?
2. What is the difference between direct
current & alternating current?
Homework: Study all notes from this week for
Monday’s Quiz.
1. What is Ohm’s
Law?
(What is an ohm?)
This states:
The current in a
wire (I) is = to the
voltage (V)
divided by the
resistance (R)
1.
2. How can we use
the magic
triangle & Ohm’s
2.
Law?
I=V
R
3.
R=V
I
V
I
R
V=IR
Recall:
What are the units
for each?
Problem:
A clothes iron is
plugged into a 120
volt outlet & uses
a current of 5
amps.
What is the
resistance of the
iron?
1. Formula:
R=V
I
2. Plug in numbers:
R = 120 V
5 amps
3. Calculate:
R = 24 Ω
Solve
1. Direct Current (DC):
3. What is the
electrons flow in the
difference
same way
between direct
ex. battery
current &
2. Alternating Current
alternating
(AC):
current?
electrons move back &
forth
The current in your
house changes direction
120 times/sec!!!
Aim: What causes electricity to turn on & (Friday)
off in your house?
Do Now: What is the difference between
direct & alternating current?
1. What is a circuit?
A complete path
through which
electricity can
flow
2. What are the 4
1. Source of energy
parts of a circuit?
(battery, outlet…)
2. A load, or
resistance
(light bulb, machine,
appliance…)
3. Wires
4. Switch
3. What is the
purpose of a
switch?
4. What is the
problem with an
open circuit?
It can open or
close a circuit
• Electrons can’t
travel through an
open circuit
• When an
electronic device is
off, the circuit is
open
Which picture shows an
open circuit?
Electricity can only flow
through a CLOSED circuit!!!
5. What are 2 types
of circuits?
6. What is a series
circuit?
Series Circuit
&
Parallel Circuit
a) It has only one path
for electrons to take
b) Disadvantage:
if there is a break in
any part, the entire
circuit is open
***NO electricity can
flow
7. What is a parallel
circuit?
A circuit that
provides several
pathways for
electrons to flow
8. What happens if
one light bulb
burns out in a
parallel circuit?
The rest will stay
lit because
electrons can still
move through the
other branches
Which picture shows a parallel
circuit?
9. What are some
circuit safety
devices?
a) Fuses
b) Circuit Breakers
•
•
They protect
against a circuit
overload
(too much current
flowing at once)
by opening the
circuit
10. How does the 3rd
prong of a plug
act as a safety
device?
a) No electricity
runs through it
b) It is connected
directly to
ground
c) Protects against
accidental shock
Aim: What is magnetism?
Do Now: Take out a piece of looseleaf
& Prepare for quiz.
1. The flow of electrons is known
as_____________.
2. As the thickness of a wire increases,
resistance ____________.
3. Give at least one example of a source of
electrical potential difference.
4. Within a wire, what opposes the flow of
electric current?
5. The units used for electric current are
__________.
6. The units used for voltage
are__________.
7. Electrons can’t travel through a(n)
_______ circuit.
8. The type of circuit that has more than
one pathway for electrons to travel is
known as a _______circuit.
9. What would happen
to the other 2 light
bulbs in the picture
if the middle light
bulb didn’t work?
10. A clothes iron is plugged into a 120 volt
outlet & uses a current of 10 amps.
What is the resistance of the iron?
Show the formula,
calculation, answer & units
V
I
R
Monday – December 17, 2007
Aim: What are properties of magnets?
Do Now: Prepare for Quiz
Homework - Study for Quiz
Test on Electricity/Magnetism on Friday
Extra Help in Room 206 on Thursday
1. What is
magnetism?
The force of attraction or
repulsion of a magnetic
material due to the
arrangement of electrons
in the atoms
Recall:
• What is a force?
• What are units of force?
• How can you calculate
force?
What is happening in each
picture?
The ends
2. On a magnet,
where is the force a.k.a.
noticed to be the
The North Pole &
strongest?
South Pole
3. What is a
magnetic field?
The region around
the magnet in
which the
magnetic force can
act
The magnetic field
lines go around the
magnet in
complete loops
from the
North Pole to the
South Pole
4. What is the rule • Like poles repel each
for magnetic
other
poles?
• Unlike poles attract
each other
5. Does the earth • Yes! It has a North
have a magnetic & South Pole.
field?
• Believed to be related
to the motion of the
Earth’s outer core
(made of iron &
nickel)
• The Earth’s
magnetic field has
changed over time.
Tuesday – December 18, 2007
Aim: How can a magnet be made?
Do Now: Prepare for Quiz
Homework - Study for Quiz
Test on Electricity/Magnetism on Friday
Operation Success this Wednesday at 3pm
Name_____________
Laws of Magnetism-Quiz
1. The magnetic field lines go around the magnet
in complete loops from the _________ Pole to
the ________ Pole.
2. Like poles __________ each other.
3. The region around the magnet in which the
magnetic force can act is called the __________
__________.
4. On a magnet, where is the force noticed to be
the strongest?_______________
5. What is a force?_______________
1. What types of
materials can
become
magnetized?
2. What makes one
material more
magnetic than
another?
Iron, Steel,
Nickel, & Cobalt
a) When the electrons
of the atoms all
rotate in the same
direction or
b) The magnetic
domains all align
3. What are
magnetic
domains?
a) They are like minimagnets
that make up the material
b) Unmagnetized materials
have randomly arranged
domains
c) Magnetized materials
have most of the domains
aligned
Which picture shows a
magnetized object? Why?
4. How can a
temporary
magnet be
made?
• Align the domains by:
1. Placing a strong
permanent magnet by a
magnetic material (soft
iron)
2. Stroking a magnetic
material with a permanent
magnet In ONE Direction
5. How can a
• Make the domains
permanent
random by:
magnet become
1.
Dropping
or
hitting
unmagnetized?
it
2. Heat it
• Materials that are
6. What is a
difficult to magnetize,
permanent
but tend to stay
magnet made
magnetized
from?
• Many are called Alnico
• Made from a mixture
of aluminum, nickel,
cobalt, copper, & iron
Wednesday – December 19, 2007
Aim: What is Electromagnetism?
Do Now: Prepare for quiz
Homework - Study for Quiz
Test on Electricity/Magnetism on Friday
Operation Success this Wednesday at 3pm
Name_____________
Making a Magnet-Quiz
1. State one way a temporary magnet can be
made._______________________________
2. Give one example of a material that can
become magnetized.___________________
3. The mini-magnets that make up a magnet are
know as magnetic _____________.
4. State one way a permanent magnet can become
unmagnetized.________________________
5. Materials that have magnetic domains that are
randomly arranged are ______________.
(magnetized/unmagnetized)
1. What is the
relationship
between an
electric current
& a magnetic
field?
A current flowing
through a wire gives
rise to a magnetic
field whose direction
depends on the
direction of the
current
2. How do you
make the
magnetic field
near a current
carrying wire
stronger?
1. Bend the wire into a
series of coils to
increase the number
of turns. (Solenoid)
2. Increase the current
(flow of electrons)
3. Insert an iron core
3. What is an
electromagnet?
a) A temporary
magnet produced by
an electric current.
b) Found in
telephones, clocks,
TV’s, car motors,
doorbells
Why does this happen?
http://education.magnet.fsu.edu/curriculum/m
aglab_alpha/maglabalpha/html/movies/elect
.mov
http://www.horsforth.leeds.sch.uk/subjects/ph
ysics/gcse/electromagnetism/images/g-phyelmag-dia08.swf
4. Can electricity Yes!!!
be made from • A changing (not steady)
magnetism?
magnetic field can
create an electric
current.
• This is an induced
current or:
Electromagnetic
Induction
How is electricity produced
from magnetism?
How does a hand generator
work?
Hand generator
Thursday – December 20, 2007
Aim: Review: What do you know about
Electricity & Magnetism?
Do Now: Prepare for quiz
Homework - Study for tomorrow’s
Test on Electricity/Magnetism
Name_____________
Electromagnetism-Quiz
State 3 Ways an Electromagnet can become
stronger
1.
2.
3.
4. What does this picture show?
5. A ____________ magnetic field can
create an electric current.
What energy transformations
are taking place here?
Fill in the “?”
The current in a simple circuit
• A simple electric
circuit contains a
source of voltage
difference ,such as a
battery ,a device ,such
as light bulb that has
resistance ,and
conductors that
connect the device to
the battery terminals.
• In a series the
current has only
one loop to flow
through. Series
circuit are used in
flash light and
some holiday light
circuit.
•A parallel circuit
contain two or
more branches for
current to move
though.