magnetism concepts

science section 3

what direction do magnetic fields go

north to south

what are the fundamental units of magnetism

magnetic dipoles with a north pole and south pole

there are no such thing as magnetically charged particles but the magnetic FIELD can exert a force on (blank)

electrically charged particles like protons and electrons

magnetic field are more (blank) than electric fields because you can (blank)

intuitive; directly observe them

you can think of the magnetic field as the (blank) in which a (blank) would point at each location

direction; compass

an individual atom itself is a (blank)

magnet

if an object’s atomic magnets are all lined up in the same direction, their magnetic fields would (blank) allowing you to see magnetism at (blank)

add together; larger scales

individual atoms of nonmagnetic objects are (blank), their atomic poles are all pointing in (blank) directions, so they (blank) and therefore you (blank) see a large-scale magnetic field

magnetic; random; cancel each other out; will not

materials like (blank) and (blank) are naturally ferromagnetic

iron and nickel

what is ferromagnetic

when they are exposed to a strong magnetic field, their atoms line up with that field and stay that way for a long time making a permanent magnet

the earliest magnets had to be (blank) from the (blank), having been magnetized by the (blank) itself

scavenged from the ground; earth

nowadays we can use (blank) to create our own magnets

strong electric currents

what is paramagentic

become magnetized as long as there is a surrounding magnetic field. the magnetism goes away when the field goes away —> don't remain as permanent magnet

(blank) fridge magnet stick to a (blank) fridge door

ferromagnetic; paramagnetic

examples of paramagnetic

fridge door, paperclips

when you remove the magnetic from a paramagnetic object, the (blank) causes the atoms to go back to (blank) and the object (blank) its magnetism

random thermal motion; vibrating randomly; loses

what analogy is used to describe paramagnetic objects 

classroom full of rowdy students line up in a well-behaved manner as long as the teacher is in the room but becomes random chaos when the teacher leaves

a fridge magnet is a bunch of what

tiny horseshoe magnets lined up so that there are alternating north and south poles along the surface

magnetic fields are produced by (blank) but only when (blank)

electrically charged particles (protons and electrons); they are moving

similarities between electricity and magnetism (3)

1) both fields are produced by electrically charged particles

2) both have opposite charges (protons and electrons; north and south)

3) magnetic fields add up and so do electric fields

differences between electricity and magnetism (3)

1) electricity has monopoles (protons and electrons); magnetism has dipoles 

2) electric field points radially away from the charge; magnetic field points perpendicular to the direction in which the charge is moving

3) to create magnetic field the particle must be moving

a stationary electron will produce what field

electric field

a moving electron will produce what field

electric and magnetic

what causes magnetism within atoms

electrons are constantly moving around within atom so the orbital motion generates a magnetic field

how does an electron have its own magnetic field

it spins, generating a magnetic field

a wire with electric current running through it creates what field

electric and magnetic

what did Hans Christian oersted observe and in what year

1820; that a wire with electric current running thru it creates a magnetic field

how did Hans Christian oersted notice that an electric current will generate a magnetic field

he noticed that a wire with current running thru it would deflect a compass

what was the first hint of a deeper connection between electricity and magnetism

the discovery made by hans Christian oersted

there is a common myth about oersted. what is it

that he discovered current will generate a magnetic field on accident, but in reality he had been researching electricity for quite some time

(blank) is required for charged particles to FEEL magnetic forces

motion

compared magnetism for a stationary electron versus a moving electron

stationary electron: no magnetic field, don’t feel magnetic field of others

moving electron: creates magnetic field, influenced by magnetic fields created by other moving charges

current-carrying wires can exert (blank) on (blank) and (blank), attracting/repelling them depending on the (blank) of the current

magnetic forces; particles and wires carrying currents; direction

what direction does the magnetic field generated by a moving charge point to

perpendicular to the direction in which the charge is moving

magnetic field lines always form

closed loops

in the right-hand rule which finger represents what

thumb - current

curved fingers - magnetic field

what counts as “moving” depends on what

your pov

physics is an (blank) science

observation-based

if we want to say the train is moving at 40mph, then we have to clarify that the train is moving at 40 mph …

relative to the ground

if a train is going 40mph in one direction and a car is driving in the opposite direction 30mph, the car would see the train go by at (#)mph relative to (blank)

70; them (car)

if a train is going 40mph in one direction and a car is driving in the same direction 50mph, the car would see the train go by at (#)mph (blank) relative to (blank)

10mph backward; them (car)

all speed/motion is (blank)

relative

depending on your (blank), the ground is moving at (blank) of mph around the (blank) of the earth

latitude; hundreds; center

the entire earth is moving at (#) mph relative to the (blank)

70,000; sun

our entire solar system is orbiting the center of the (blank) at over (#) mph

milky way galaxy; 100,000mph

earth rotates on axis

> 1000 km/hr

earth orbits sun

> 100,000 km/hr

solar system moves among stars

~70,000 km/hr

milky way rotates

~800,000 km/hr

movement within local group

~300,000 km/hr

universe expands at

70 km/s/Mpc

in our daily lives, it makes sense to define all motion relative to the (blank).

ground

is the statement “all motion relative to the ground” fundamental why or why not

it’s not fundamental because the ground beneath your feet is in constant motion relative to the rest of the universe

we measure speed relative to the

ground; but there is no law of physics that specifies a particular frame of reference

there is a long straight wire with current rushing to the right (meaning electrons are moving to the left). your friend moves in the same direction and speed as the electrons. to her what will she observe

me and the wire moving; electrons in wire are stationary; no current in the wire —> no magnetic field

what color is Aurora borealis on saturn

blue

why is magnetic field not a fundamental force

the magnetic field does not appear to everyone it depends on the observer

the magnetic force only AFFECTS (blank) charges

moving

if a proton moves thru a magnetic field and another observer moves with the proton, to the observer the proton will be (blank). stationary protons (blank) experience a magnetic force 

stationary; will not

forces are relative or not?

not relative; you can disagree on the speed of a train when you watch it pass by vs sitting in it, but you cant disagree on the existence of gravity

the word “magnet” originates from where

coastal district Magnesia in Greece

what was found in magnesia

iron-attracting lodestones

when exactly were the first compasses invented

unknown

compasses were in use in (country) for navigational purposes as far back as the (#th) century

china; 11th

before compasses, navigators could only determine direction using (blank) and (blank)

sun and the stars

what is the advantage of a compass

it points north even on a cloudy day

a typical compass is made of what

small piece of magnetic iron floating in a liquid allowing it to freely rotate

the north pole of the compass is attracted to which pole of earth? what about the south pole of the compass?

north pole of compass attracted to earth’s south pole; south pole of compass attracted to earth’s north pole

what makes the compass needle rotate around its center

one pole is pulled to one direction and the other pole is pulled in the other direction

when a magnet is exposed to another magnetic field what happens

it aligns its poles with the surrounding magnetic field

the earth’s magnetic field points towards earth’s MAGNETIC (blank) pole so the compass aligns itself such that it also points toward earth’s MAGNETIC (blank) pole

south (for both blanks)

the earth’s GEOGRAPHICAL north pole (arctic) is earth’s MAGNETIC (blank) pole

south

the earth’s GEOGRAPHICAL south pole (antarctic) is earth’s MAGNETIC (blank) pole

north

the magnetic field of the earth is generated where

within earth’s core which is made of molten metal

as the earth spins what does it generate through the molten core

electric currents

what is the dynamo effect

as earth spins, its molten core generates electric currents creating a planet-wide magnetic field

the magnetic poles (do/do not) precisely line up with the roatation poles

dont

the (north/south) magnetic pole slowly wanders year to year

south

does the compass actually point directly north (geographically)? why or why not

no, it points a few degrees away from north because the south magnetic pole slowly wanders

earth’s magnetic field (blank) (blank)

reverses polarity

the magnetic poles are switched every (#) yrs to (#) years with no (blank)

1,000-100,000; pattern

the magnetic north pole is in the (palce) and the magnetic south pole is in the (place)

antarctic; arctic

how do we know earth’ s magnetic poles are switching polairty

when certain rocks are molten, they can become magnetized by a surrounding magnetic field and when solidified it retains the same magnetic polarity

earth’s surface is broken up into

tectonic plates

why do tectonic plates slide next to each other

heat of the earth’s interior

how many years can it take for a tectonic plates to move

over many millions of years

one boundary between the plates stretches across the (blank) and in this area the plates are gradually moving (blank)

atlantic ocean; apart

what happens as the gap widens between tectonic plates

molten rock seeps up, cools, and solidifies to become new ocean floor. as the seafloor spreads, it retains the magnetic field direction of the earth when the rock solidified

most dangerous object in space

sun

sun is a big ball of (blank)

plasma

what is plasma

type of gas so hot that the nuclei cannot hold onto any electrons so it is a gas of a bunch of protons and electrons moving around independently

the elctrficied gas (plasma) results in strong (blank) which in turn make their own (blank)

currents; magnetic fields

as the sun rotates, its magnetic field can get (blank) by the (blank)

twisted; rotating plasma

the rotating plasma causes what

patches of sun’s surface to get cutt off from the rest of the surface and cool off

the cool spots are (darker/lighter) than the rest of the sun which is why they are called (blank)

darker'; sunspots

sun’s magnetic pole switches every (#) years

11

when the sun’s poles are about to switch what happens

a lot of sunspots appear due to magnetic twisting

when the magnetic field gets so twisted what can happen

coronal mass ejections: plasma gets stretched out causing chunks of the sun’s surface to get ejected off the sun entirely

what happened to the hot balls of plasma ejected from the sun’s surface

most fly off into space and don’t hit anything, once in a while it’ll hit earth

one example of a big coronal mass ejection that hit earth

the Carrington event