Unit 8: Magnetic Fields Flashcards
What did ancient mariners as compasses?
Magnetic rocks containing iron (lodestone).
Two ends of a magnet behave very differently because magnets are __________; they have 2 opposite ends, called _____________
polar
poles
the north pole is actually near where?
the earths south magnetic pole
the earths south geographical poles is actually near where?
the earth’s north geographic
what will a bar magnet do always when it is suspended and allowed to rotate freely
it will always align itself with the magnetic field of the earth
no matter how small you break a magnet, what will it always have?
a north pole and a south pole
law of magnetic poles
magnetic poles that have the same polarity will repel each other
magnetic poles that have opposite polarity will attract each other
magnetization by contact
when a permanent bar magnet touches an object such as a nail, the bar polarizes the nail, making it a temporary magnet
what do magnets attract?
other metals such as nails, paper clips, tacks, even though they are not polarized
what metals are not attracted to metals
aluminium, copper, brass
what metals are strongly attracted to magnets
iron, nickel, cobalt, and gadolinium
what do you call materials that can become temporary magnets
ferromagnetic
how do you permanently magnetize a nail or a screwdriver?
Rub it with a permanent magnet
Hit it with a hammer when the nail or screwdriver is aligned with the Earth’s magnetic field
a group of neighbouring atoms whose poles are aligned
magnetic domain
where do the domains point in a ferromagnetic material that is not magnetized
random directions
where do the domains point in a ferromagnetic material that is magnetized
roughly the same direction
no domains
non-magnetic material
domains, but not lined up
magnetic material
domains, and all are lined up
magnet
why does the earth have a magnetic field
The core of the earth is a solid sphere composed mostly of iron and nickel. The magnetic domains of the earths core are aligned
what is the earth composed mostly of?
iron and nickel
World Magnetic Model
a program that helps your phone navigate. it improves the navigation of devices ranging from nuclear submarines to common smartphones
Why is the WMM in trouble
the Earth’s magnetic field is changing
How often is the World Magnetic Model updated
5 years
