1. What do these have in common?

2. II. All magnets have a ___________________________.
north and south pole N S
If you break a magnet… N S
will become an entire magnet
…each piece ________________________________: N S N S
If you break it again, each piece will _____________
_____________________. A separate, single, N or S
magnetic pole (called a ________________ ) has
_____________________________ .
again have
both a N- and S-pole
monopole
never been observed

3. Earth has a magnetic field that is __________________
the field of ______________________.
similar to
a bar magnet
magnetic
true
______________ axis
________ axis S
_________
bar
magnet
Earth N
_________
Earth’s B field:
--protects the planet from ______________________
--produces the _________________________________
--at the surface is a result of the magnetic effects of:
a/ __________________________________________
b/ __________________________________________
c/ __________________________________________
d/ ___________________________________________ -
cosmic rays
borealis (northern) lights
rotating currents in the outer core (90%)
magnetic rocks in the crust
electric currents in the ionosphere
ocean currents

5. The Origin of the __________________________ :
Charged particles from the Sun
experience a ________________
force that is _________________
to their ______________ and to the
____________ field. This is a
________________ force Fc that
causes them to _____________
around the B field. As they
spiral down to Earth, they knock
___________ out of atmospheric
________ . When these electrons
_______________ with their atoms,
they ___________________________ .
aurora borealis
path of a
_________
particle
magnetic
charged
perpendicular
velocity
magnetic
centripetal
spiral
electrons Fc
____ due
to B field
atoms
re-combine
B field
_______
line
emit light of different colors

8. Earth's field makes an angle to its
surface called the _________________________.
inclination
What is the
angle at the
poles?
equator?
900 00

9. The N- and S-poles of Earth’s B field:
a/ are not the same as the __________ (true) poles
b/ _____________________________
c/ Sometimes ____________ polarity so that
____________________ and vice versa. The last
time this occurred was about ____________ y ago
spin
slowly wander around
reverse
N becomes S
750,000
Magnetic ___________________ is the angle that the
_______________ north makes with _________ north.
declination
magnetic
true
130
In Poughkeepsie the
declination
is about ___________
magnetic
true
__________
north
________
north
130 W

10. 130 magnetic N pole The wandering _______________________ New York

12. Neutron stars are large stars that have collapsed
until they are planet sized. As they collapse, their
magnetic fields intensify. As they rapidly rotate, their
magnetic field sweeps around like a lighthouse.
They were originally called pulsars.

13. The Sun’s magnetic field…
produces sunspots
reverses itself every 11 y
(next peak: 2012….)
3. affects climate on Earth.

14. __________________experiment (1819 in Copenhagen): Oersted’s
wire S N
compass
battery
switch
An electric current ___________________________.
 Currents, I, _____________________________.
________________ and Magnetism are closely related.
Each one can induce (give rise to) the other. This is
the basis for the ______________________ generation
of power .
deflected the compass
cause magnetism, B
Electricity
electromagnetic

15. I. The Magnetic Fields of Current-Carrying wires:
Experiment: Hang a _______ vertically. Support a piece
of paper horizontally. Turn _____________. Sprinkle iron
filings to see the ______________ pattern.
current on
B field
right hand
The _____________ rule
tells you which one of
the two possible ways
that the B field points.

16. > > The B field of a long straight wire has the shape of
_________________________ .
concentric circles
View directly at
wire with I towards
you: I
> B B B
side view:
> I

17. Ex: Twist a wire into
the shape of a _______.
coil
coil I
The B field of the
coil is shaped like
a _______________:
Side view:
bar magnet N N S S

19. _______________________ are magnets made with coils.
They are also called ____________________ .
To strengthen its B field, use:
_______________________
______________________
__________________________
Electromagnets
solenoids
more current
more coils
a ferromagnetic core Fe C o r e

20. What are electromagnets used for?
Plus electric motors
and generators…

21. The B field of the electromagnet
turns its iron core into a magnet.
The core will then be attracted
into the coil's field.
 This is how solenoids work.

22. Analog ammeters (and voltmeters) use coils, too:
Current is used in coils to create electromagnets.
The electromagnets repel/attract and move the needle.
The stronger the current, the more the force, and
the more the needle moves.

23. Magnetism in solids is caused by the ______________
II. Magnetism in Solids.
Magnetism in solids is caused by the ______________
that result from the motion of ________________ as they
1/ _____________________________ , or
2/ _____________________________ within each atom.
currents
electrons
"spin" on their axis
"orbit" their nuclei
An atom:
e- spins
on axis
e- orbit
nucleus
Think of a
spinning
electron:
as a tiny
_______
___________: S
bar
magnet N

24. amazing Isn't it that Earth's magnetic field is similar to of an
electron!!!!

25. Types of magnetism:
ferromagnetism:
--___________________ attraction
--only in ______________________
--caused by ___________________electrons that
act _______________________
strong
Fe, Ni and Co
unpaired
cooperatively
Why ferromagnetism only occurs in certain atoms:
Electrons can only "fit" in certain _______________ around
the nucleus called _______________ . At most, only ___
electrons, spinning in ________________ directions, can fit
in each _______________ .
positions
orbitals 2
opposite
orbital
orbital
= represents an electron ______________ in an atom
one way
= represents an e- spinning ______________
the other way
= represents an e- spinning ______________

26. Each element has its own ______________ arrangement
of orbitals and ______________ of electrons. Whether
an atom is ferromagnetic or not depends on whether
the ________________ are _______________ or not.
unique
number
orbitals
filled up
not magnetic
filled
cancel
= ________ orbital  spins ________  _____________
unfilled
ferromagnetic because
spins act like magnets
= _________ orbital  __________________________
 __________________________
diamagnetism:
--weak magnetic ________________
--occurs in water, glass, Cu, Pb, salt, wood,
most gases, plastics, etc.
repulsion
paramagnetism:
--weak magnetic _________________
--Al, O, Na
attraction

27. In a ferromagnetic solid (iron, nickel or cobalt), atoms
with unfilled electron orbitals organize themselves into
domains -- area in which the electrons are lined up
Ex. An unmagnetized ferromagnetic material has
random domains:
= spin of
an electron
domains
Ex. A magnetized ferromagnetic material has domains
that are aligned with each other
external magnetic
field

28. What kind of field surrounds …
caused
by:
Field
mass m
1. a neutron at rest?
gravitational g
gravitational g
mass m
a proton or an
electron at rest?
electric E
charge q
gravitational g
electric E
magnetic B
a moving* proton
or electron?
mass m
charge q
current I
*The motion is _________________ . This means that
you will also measure a B if the charge is __________
and you _________________ .
"relative"
at rest
past it

29. Uses of strong magnetic fields:
_______________________________________
______________________________________
_____________________________________
To produce strong magnetic fields,
___________________ are needed. But this causes
______________ or ___________ heating. To reduce
the heating, ____________________________ are used
because they have no __________________________.
medical - NMRs
power transmission
transportation – maglev trains
computer memory
research – contain fusion reactions
high currents
joule
I2R
superconductors
resistance