magnetism

opposite poles

attract

like poles

repel

non contact force

a force that acts between objects that are not touching

non uniform field

field strength is not the same everywhere

uniform field

field strength is the same everywhere

three magnetic metals

iron nickel cobalt

permanent magnets

always have a magnetic field around them

temporary / induced magnets

only have a magnetic field when they are placed in another magnets magnetic field

electromagnets

only have a magnet field when there is a current flowing through them

ways to increase the strength of an electromagnet

increase current 

increase number of turns in coil

add an iron core

force on wire calculation

f = b x i x l

magnetic field points

north to south

current goes from

positive to negative