Transcript A Magnetic Force

PG. 79
EQ: How are electricity and
magnetism related and how does it
affect our every day life?
PG. 79
ELECTRICITY
The movement of electrons from one
place to another
MAGNETISM
A material that has aligned domains
with repulsive and attractive forces
ELECTRICITY
MAGNETISM
Electric currents cause magnetism
►
How can you tell?
Compass needle moves when
near electrical current creating a magnetic field
ELECTROMAGNET
A temporary magnet made by wrapping a wire coil
carrying an electric current around an iron core.
How to increase the strength of the
magnet



More coils of wire= more current
Increase voltage
Add iron to the core
https://www.youtube.com/watch?v=lSmuqLtmuwg
Junkyard electromagnet
Increasing the strength of the
magnetic field
(1-weakest, 4 –strongest)
3. Solenoid - A
single wire wrapped
into a cylindrical
wire coil
1. Straight wire
2. Single loop
4. Solenoid with
iron core
► Electric
motors are used in most household
appliances which convert electricity into
mechanical energy (motion).
How does an electric motor
work?
How does an electric motor work?
Go to the next slide 
How does an electric motor work?
Simple as that!!
How a speaker works
https://www.youtube.com/watch?v=DMxn3CPLe-A
MAGNETISM  ELECTRICITY
Moving magnet can generate electricity
►
How can you tell?
Electromagnetic induction
moving a magnet in and out of a
coiled wire created an electrical
current without a battery
https://www.youtube.com/watch?v=AmWEs5CTQ3Q
https://www.youtube.com/watch?v=20Vb6hlLQSg
Electricity generation
https://www.youtube.com/watch?v=hajIIGHPeuU
Moving a loop of wire through a magnetic
field or moving a magnet through a loop of
wire produces an electric current.
https://www.youtube.com/watch?v=S3Qwf4P6x9w
Flashlight
https://www.youtube.com/watch?v=NqdOyxJZj0U
Pipe and magnet
A generator is used to
convert mechanical energy into electrical
energy by electromagnetic induction.
Dilbert
Maglev Trains
► Maglev
trains are the new way to travel. It
uses both magnets and electricity to cause a
train to “levitate” above the track (and
reduce the resistance of friction).
► Video:
►
https://www.youtube.com/watch?v=iaElPV0FWJ0
Changing Voltage
►
Transformers work by the ratio of coils
to change voltage:
 Changing magnetic field
strength: If you have more
coils on the output side
than the input side, then
you increase voltage. If
you have less coils on the
output side, then you
decrease voltage.
 Video:
►
https://www.youtube.com/watch?v=YQQ-mgjCpn8
SUMMARY OF E & M
E = Electricity and M = Magnetism are related!!
ELECTRICITY
• Both can cause
each other
►
Can be + or -
►
Can flow (current)
►
Can jump (static)
• Likes repel
MAGNETISM
►
Can NOT have only
1 pole
►
Can be Normal (N)
or Reversed (S) pole
►
Can move through
field
►
Causes sun spots,
flares, CME
• Opposites attract
Closing Task
►Differentiate
between an
electromagnet and
electromagnetic induction. How
are both used in your every day
lives
► An
electric motor is a device which converts
electricity to mechanical energy.
► An
electromagnet turns inside of a permanent
magnet. By changing the direction of the current,
the poles will keep switching between N and S, and
therefore cause the electromagnet to continually
rotate.
► Electric
generators do just the opposite. They
convert mechanical energy into electricity.
► They do this through a process of electromagnetic
induction. This is where an electric current is
generated by manually varying a magnetic field.
https://www.youtube.com/watch?v=d_aTC0iKO68