@Lozansky So...what is the output of your simulation?

Have you written a simulation that just updates a graph but never actually exposes the data that's being drawn?

@ACuriousMind Wait, I'll try and make a gif

@ACuriousMind You still there?

I had to install ffmpeg :P

gfycat.com/GrandMindlessBlackmamba

So I only want the data from the last frame

@ACuriousMind hi, are you moderator?

@Morata Hint: If someone's name is blue in chat, then they're a mod somewhere on an SE site. If you click on their name, then on "user profile on [site].stackexchange.com", the page will have (in this case) "ACuriousMind♦ (moderator)", showing they're a mod on physics

@Morata Yes, as you well know. You and your sockpuppets are still not welcome here.

6 messages deleted

@Lozansky wow nice work thats super cool think itd be cool if you wrote it up on a blog somewhere, can help more if you do :)

@Lozansky Sure, but I'm not sure what the problem is with that - presumably you have a function that computes the values that should be drawn, and another that actually draws the data, so you can just intercept the output of the first function and saves it.

If you've programmed in a way that doesn't make this easily possible, then this is a good practical lesson about the importance of separation of concerns ;)

@ACuriousMind Yeah I figured it out :P

I did the ugly way of saving the y-data after every time step

Evening.

Time for some Kerbal Space Program

Ah, good choice ;)

I read a book (for 2 days) on how to build a model rocket and I'm hooked :D

@JakeRose The E-field is only conservative in electrostatics, i.e. when there is no time-varying magnetic field

Ahhhhh

All we have covered is electrostatics you see

How can the E field not be conservative still though?

I thought it was a fundamental property of the field?

@NovaliumCompany What level of physics/maths are you at?

e.g. are you at a university?

@JakeRose Well...it just isn't. The fundamental equations of electromagnetism are Maxwell's equations, and they imply that the electric field is conservative if and only if there is no time-varying magnetic field

Okay fair enough

Maxwells equations are wednesdays lecture fortunately

one neat little thought experiment for why you need Faraday's law is to consider a bar magnet entering a closed loop of wire

If you consider the bar magnet as being fixed and the closed loop as in motion, then the free electrons in the loop will have an overall velocity and therefore will be subject to a lorentz force from the diverging field lines of the bar magnet

consequently, in the frame of reference of the bar magnet, one deduces that there's a net magnetic force on the free electrons

on the other hand, in the frame of reference of the loop these electrons are all at rest to start with.

and since the magnetic force on charged particles at rest is zero, the magnetic field (which is necessarily time-dependent) present can't make the electrons start to circulate i.e. the magnetic field can't produce a current in this reference frame

So you need an electric field that'll make the electrons start to move. Since the required electric field would have to circulate along the loop, it won't be conservative. Hence it has to be the case that a time-varying magnetic field goes hand-in-hand with a non-conservative electric field.

Mhmm interesting

@Semiclassical Got any popular science (physics) books youd recommend on audible?

Just finished harry potter so Im running out of ideas

not really, no

shame

Whats the meta chat for ?

@JakeRose It's generally for any sort of "overflow" conversation that doesn't suit the main chatroom and currently contains a lot of back and forth about chat moderation.

@JakeRose Everyone who's a moderator on a main site; our names appear in blue here and have a diamond behind them in the window that pops up when you click on a name/picture

Ahhhh I see

Good evening.

Is there anybody that can help me, please?

I'm searching a book where i can find this argument. Yet I have not any answer.

@ACuriousMind Do you know a book where I can an exahustive explanation?

@Sebastiano 'fraid not, I'm not big on textbooks and I don't think I've ever thought about Snell's law in relativity, anyway

@Sebastiano Sorry, I forgot about this! I think you may have more luck if you put a bounty.

You might want to get rid of the derivation entirely and just edit your question to, how can one derive the law of reflection for a moving mirror in relativity? The derivation is so confusing I think it makes it harder.

@Sebastiano Actually, on second thought I put on a bounty for you. Good luck finding an answer!

@knzhou Thanks. Now I have edited my answer. I hope that it let be very clear.

@ACuriousMind Thanks again.

Bye to everybody.

I've got a quick question that I'm not sure is appropriate for the main site... does anyone know of any sources on the "arc strike" phenomenon (where gas stays ionized after an arc is struck, even at a lower voltage)? I've been searching around for ccfl and fluorescent tube papers et al, but I'm drawing a bit of a blank...

(specifically I'm trying to find out whether a stream of gas also has this property, or if it needs to be the same gas molecules as were struck, like in a closed florescent tube)