/sci/ - Science & Math

[Anonymous No.3311706]

Dear /sci/

How do magnets work?

[Anonymous No.3311718]

They attract metal.

[Anonymous No.3311724]

fuckin electrons n shit

[Anonymous No.3311728]

bump

no fucking clue how they work

[Anonymous No.3311731]

They LOVE metal.

[Anonymous No.3311733]

>>3311724
Faeces are not involved at all, I assure you.
Nor do the electrons copulate.

[Anonymous No.3311737]

OP here

> They attract metal

how?

[Anonymous No.3311756]

there is a magnetic field that runs from the nord pole to the south pole ( of the magnet) this attracts metal

[Anonymous No.3311758]

>>3311733
fucking faggot

[Anonymous No.3311765]

>>3311737
Because they're magnetic.

[Anonymous No.3311768]

>>3311733
Unlace your shoes and hang yourself.

[Anonymous No.3311773]

>>3311756
but how come when you break one up in half it gets itself as a new north and south pole

[Anonymous No.3311777]

Sorry, people on /sci/ don't really know too much about magnets. But there's a really great website called Mormon.org where you can ask people via chat, I hear they know a lot about magnets!
You can also email them at [e-mail]

Also sage

[Anonymous No.3311778]

>>3311765
>>3311737
Fucking circles, how do they work?

[Anonymous No.3311783]

>>3311733
fyi the magnetic force is calculated by the formula F=qVXB or the charge of the object multiplied by the cross product of the velocity vector with the magnetic field vector

[Anonymous No.3311794]

circular logic is circular

[Anonymous No.3311800]

>>3311773

They become bipolar.

[Anonymous No.3311809]

Is this the south pole you speak of?

[Anonymous No.3311812]

>>3311783
great job reading your physics textbook, now what the fuck does it mean

[Anonymous No.3311819]

bump

[Anonymous No.3311844]

>>3311783
The question wasn't "What is the equation for magnetic force?" The question was "How do magnets work?"

[Anonymous No.3311848]

FUCK FUCK FUCK DUCK

[Anonymous No.3311849]

Why metal?

[Anonymous No.3311854]

>>3311777
My life challenge, convert one of them, in the chatroom.

[Anonymous No.3311861]

CUNT CUNT CUNT PUNT

[Anonymous No.3311863]

>>3311854
Playing the part of a teenager shielded from religion, but curious.

Asking "how does that work, how do you know" to everything.

[Anonymous No.3311886]

i'm trolling their chatroom

[Anonymous No.3311890]

the magnetic force is caused by moving charges. For example, in a straight wire, there is a magnetic field that surrounds the wire in concentric circles. in this case, the field strength (B) is proportional to the I/d where:
I is the current in the wire and d is the distance from the wire.

If you close the wire into a loop, so that the current runs in a circle, the magnetic field lines will go out the top of the loop, circle around outside the loop and come to re meet themselves in the bottom.
When outside the loop, the field strength (B) is proportional to the I / d^3 from the center of the loop

Now, we can approximate atoms as having electrons whirling around them, forming current loops. The direction of the field is related to the spin of the electron in question.

Often, electrons pair up in orbitals, so when one is spin up, the other is spin down so the magnetic fields cancel.

In some materials, an electron is unpaired, so the atom becomes a little magnet. These are materials (like iron) that will react to magnetic fields, since a magnetic field will cause their electron spins to align. Once aligned, the iron is a magnet itself, and can be moved by the field.

In permanent magnets, the spins of electrons in the material are held in alignment by the structure of the material, so they are always magnetized on the macro scale.

Now, magnetized materials feel a force when placed in a non-constant magnetic field, attracting or repelling.

[Anonymous No.3311909]

>>3311890
Now, why do moving charges create magnetic force at all?

[Anonymous No.3311927]

>>3311909

You can habe a look at the Maxwellequations. They say that a changing E-Field causes a B-Field and vice versa

[Anonymous No.3311933]

>>3311909

The combination of relativity (changing reference frames and length contraction) and electrostatics create magnetism.

http://en.wikipedia.org/wiki/Relativistic_electromagnetism

[Anonymous No.3311944]

>>3311933

Here's a more concise site

http://physics.weber.edu/schroeder/mrr/MRRtalk.html

[Anonymous No.3311958]

>>3311927
Can you explain them?

[Anonymous No.3311967]

>>3311909
To keep consistent with relativity.

A charged object moving perpendicular to a constant B-field will follow a circular path

For example:
Imagine electrons flowing through an infinite wire with protons at rest, and a single electron outside moving perpendicular to the wire.

In the protons' rest frame, the wire has no net charge.
However, due to length contractions, when viewed from the outside electron's rest frame, the distance between each proton is different from the distance between each electron inside the wire. Thus, depending on which way the outside electron is moving in relation to the rest protons, the wire will be either positive or negative in the outside electrons rest frame, so it is attracted to or repelled from the wire.

However, in the proton's rest frame, there is no charge on the wire, so it seems like the outside electron is just bending. Hence, there has to be a force in the protons rest frame, which can be modeled by having a magnetic field

[Anonymous No.3311972]

They work better in >>>/b/

[Anonynony No.3312008]

A better question would be: What is the substance of the magnetic field? Is it some type of photon? What is "reaching through space" to attract or repel another object that is influenced by it? What is it made of?

[Anonymous No.3312014]

>>3311958

Take this formula.
dE/dt means the amount of change over time of the E-field produces a B-field
The nabla-symbol in front of the B means, that the E-field is rotating

[Anonymous No.3312032]

magnets work in the following way:


atoms or molecules have a non-symmetric electron distribution (or organization).

for metals, this is caused by 2 factors: the shape and "filling" of the d-orbitals, as well as the specific crystal structure of the metal lattice.


if the metal has "un paired electrons" the spin of these electrons will produce a net magnetic field that is not "canceled out" by a "paired" electron in the same angular momentum state.


if there are 2,3,4, or 5 unpaired electrons (maximum for d-orbitals), the fields created by each electron can "add" or "subtract" with the field created by the other electrons.

the "adding" occurs when the orientation of the spins are parallel. the subtracting occurs when they are perpendicular.


I will not pretend to understand how natural materials develop a net magnetic field, because It would seemingly involve "self interaction" in order to achieve this result, but I digress. Perhaps the magnetic field of the earth.... or the sun/planet (in the case of asteroids or comets) is what allows a net magnetization to develop... I have no idea.


if enough "local" (nearby) atoms or molecules ALSO have un-paired electrons whose spin is oriented in "roughly" the same direction as their neighboring atoms...


then, when you add up the effect from all of the atoms, the entire chunk of material exerts a "macroscopic" field.

[Anonymous No.3312037]

>>3312014
"I know vector calc!
Del cross = spiny thingies!!!"

HURRRRR

[Anonymous No.3312044]

>>3312037

Del cross B, mister.

[Anonymous No.3312056]

>>3312037
Wtf? this is not delta, this is nabla

[Anonymous No.3312061]

>>3312044
You completely forgot the current, and this does not mean the E-field is rotating.

Also, Del cross = spiny thingies!!! is your idea of curl in general.

[Anonymous No.3312068]

>>3312056
del = nabla, dumbass
del != delta

[Anonymous No.3312069]

cool a question general thread!
How do gamma rays work?
I've read somewhere that gamma rays can travel faster than the speed of light. is this true?

[Anonymous No.3312079]

>>3312069
nope, they are a form of high energy light.

Energy levels:
visible<UV<X-rays<Gamma-rays

All are EM radiation

[Anonymous No.3312083]

>>3312069

no, its not because they are light

[Anonynony No.3312086]

We know what causes a magnetic field, but what is this field made of? It's invisible, works in a vacuum, isn't stopped by materials unaffected by the field. What is the SUBSTANCE?

[Anonymous No.3312091]

>>3312061

I am not the guy that posted that picture. I was being facetious. You can turn off your fire hose now.

[Anonymous No.3312095]

>>3312079
but foxnews disputes that claim here
http://www.foxnews.com/scitech/2010/01/19/whats-faster-light/

[Anonymous No.3312100]

>>3312086

A magnetic field is an electric field in another frame of reference. They are carried by the same particle.

[Anonymous No.3312110]

>>3312091
FULL BLAST, BITCH!!!!!!

[Anonymous No.3312128]

>>3312069

no, but certain types of high energy particles can travel faster than the speed of light IN A SPECIFIC MEDIUM (though, not faster than the speed of light in the vacuum).


this produces Cherenkov Radiation.

[Anonymous No.3312139]

>>3312100


pretty sure that is not true.


there is no guage or symmetry that converts a monopole into a dipole.


and their relative strengths are massively different.

[Anonymous No.3312142]

>>3312091
That was me.

I got this pic from here: http://en.wikipedia.org/wiki/Maxwell%27s_equations#Table_of_.27microscopic.27_equations

[Anonymous No.3312144]

>though, not faster than the speed of light in the vacuum
except it can, but it gets absorbed to fast to break causality.

[Anonymous No.3312155]

>>3312139
I'm pretty sure it is.
Remember, he is talking about the fields, not the particles

[Anonymous No.3312168]

>>3312155


right. Magnetism is governed by a different set of physical laws

we define a different potential field to describe it (the magnetic vector potential), even in the context of relativistic calculations.

[Anonymous No.3312214]

>>3312168
Yes, but We only use vector potentials for B-fields and scalar potentials for E-fields because there are no magnetic monopoles.


When we talk about a region of space with E and B fields, but no charged particles, the E field and B field will interchange with each other depending on the frame.