Thread: physics e/m question
01-18-2006, 04:28 PM #1
physics e/m question
ive been asked to prove that electric fields exist. after thinking about it for awhile i decided that i should say that lightning proves this, because when it strikes, it is evident of an electric potential which is associated with an electric field. anyone got any ideas on this? im sure johan will have some input
01-18-2006, 04:32 PM #2
what about static electical shocks and stuff like that
01-18-2006, 04:34 PM #3
yea i was thinking about that too. actually any type of electrical discharge would work i think
01-18-2006, 04:37 PM #4
proofOriginally Posted by Tren Bull
But the best visual would be to use a magnet and steel filings. Does he want you to prove it mathmatically(using Coulomb's law) or graphically?
01-18-2006, 04:39 PM #5
only conceptually. i can imagine that proving it mathematically would be pretty hard
01-18-2006, 04:47 PM #6Originally Posted by Tren Bull
I dont think it would be as hard as you think....maybe with the weight of electrons, neutrons and protons and crap like that. Yeah i forgot all my physics stuff.
01-18-2006, 04:57 PM #7
all things considered, i really dont like proofs or long winded derivations. proofs damn near killed me in linear algebra, and that class isn't even really that hard.
01-18-2006, 04:58 PM #8
btw, are you really russian? i heard they make kids take calculus during elementary school there.
01-18-2006, 05:01 PM #9Originally Posted by Tren Bull
Calculus is taught in middle school, I lived in Russia for extended periods of time but was never actually schooled there. There education system beats the ever loving shit out of ours.
01-18-2006, 05:05 PM #10
electromagnetic and electric fields co exist! Ultra violet rays are a prime example of this.. Or any frequency in an electronic device!
01-18-2006, 05:23 PM #11
Just show them a picture of a speaker.
01-18-2006, 05:34 PM #12
i was taught that the magnetic field is a consequence of the electric field. did you know that gravity fields, and e&m fields all create surface pressure the same way a gas does? that means that these fields actually consist of small particles. fu_kin weird. you know what else really trips me out? theory of relativity.
01-18-2006, 06:43 PM #13
what about arhcing... or how nothing electrical will work after a nuke is detonated
01-18-2006, 09:20 PM #14
today i was thinking about how crazy it would be if somehow we managed to make a space ship that could go the speed of light. if we actually acheived that, and got the ship going the speed of light, according to its passengers reference frame, instantly the ship would reach the end of the universe. and then what? does the universe even have an end to it? according to earths reference frame, it would take an infinite amount of time for the milisecond that the passengers on the ship would feel... i swear, relativity totally defies my seemingly logical understanding of space and time... btw, nukes are crazy... one of those things i wish we could disinvent.
01-18-2006, 09:43 PM #15Originally Posted by Tren Bull
You could also place an electromagnet under a piece of paper, then sprinkle some iron filings on top and watch them allign themselves along the lines of force.
Just two quick ideas . . .
02-03-2006, 06:57 PM #16Originally Posted by Tren Bull
A field is just a mathematical concept that works imo.
Technicaly according to quantum electrodynamics(I have zero experience with QED so dont take my word for it) I dont think the field exist as a separate thing. The em force is just because of virtual photon exchange and that exchanged can be aproximated macroscopicly by the EM field equations
02-03-2006, 07:11 PM #17Originally Posted by Tren Bull
Originally Posted by Tren Bull
What I love the most is relativity of simultaneity. Its just so wierd to think that "right now" here isnt the same as "right now" in a different part of the universe. That 2 events that one observer se as simultaneous isnt simultaneous from someone elses perspective. What is even more fascinating is that both of the observers are right. Some sci-fi author should realy try to mix this into a work of fiction. Especialy when there is faster than light travel involved. that would screw up simultaneity tremendously.
What I hate though is the light speed limit. Its depressing I realy hope something will allow us to shortcut it
02-03-2006, 08:05 PM #18Originally Posted by johan
i was thinking about how it kinda sucks that the speed of light is theoretically the fastest anything can go, but after studying relativity for awhile i learned that the distance between any two points decreases the faster you go. therefore if you were to go at exactly the speed of light, your trip would seem instantaneous, but you technically would have traveled damn near an infinite distance because the relative distance between say earth and a planet 56 billion light years away would be so significantly decreased... the bad thing is that according to earth's reference frame, it would take 56 billion years for you to make that trip. then it would take another 56 billion years for you to make it back to earth... by that time our sun would have burned out, and destroyed our solar system... weird man... fu_kin weird.
Last edited by Tren Bull; 02-03-2006 at 08:09 PM.
02-04-2006, 04:48 AM #19Originally Posted by Tren Bull
to get to those speeds with chemical propelants would require more reaction mass than the whole mass of the universe though. So we would have to invent totaly new ways of space travel. Some kind of field drive if that is ever possible.
Pic up revelation space by Alastair Reynolds in his books they can only travel close to speed of light and he has realy given it serious thought.
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