If your name's not Maxwell you're not coming in

[boyofbadgers]

[Poll #588764]

Comments

[wintrmute.livejournal.com]

Have to admit it sounded familiar, but couldn't place it. Just read up on the Wikipedia entry though, but that's cheating. A Ranque-Hilsch vortex tube (http://en.wikipedia.org/wiki/Vortex_tube) sounds wonderfully Sci-Fi :)

[dubdobdee.livejournal.com]

maxwell edison majoring in medicine!!

the maxwell demons is the name of eno's first band!! (i think) (they may have beeen "conceptual" --- they appear for "real" in velvet goldmine

[marnameow.livejournal.com]

I have that choon stuck firmly in mine head now.

I am going to donate Robot the cat to physics* because clearly physics needs *actual* creatures in boxes and she's very good at being in boxes.

*Except I'm not because I'd be sad and she'd be sad.

[sbp.livejournal.com]

You're thinking of Schroedinger

[beckyc.livejournal.com]

I think probably my first introduction to Maxwell's demon was when I read the Mr Tompkins stories (Gamov) when I was about 13 or 14 or so. But then I went on to do a physics degree, so it's hardly suprising that I'm aware of Maxwell's works.

[katstevens.livejournal.com]

Oh, it's SCIENCE. Yesterday was Science Day, I declare that today is... Not Science Day.

I don't think we did him for A-level Physics. Only Hooke, (Line and Sinker oho)

[the-roofdog.livejournal.com]

MAN OF SCIENCE, MAN OF FAITH !

Ohhhhhhhhhhhhhh, you haven't got to that episode yet, have yoo ?

[jauntyalan.livejournal.com]

oh yes. mind i've got ep 3 to see yet - tomorrow while downloading ep 4 :-)

[boyofbadgers.livejournal.com]

Hahaha, as though THAT wasn't easy to predict.

[katstevens.livejournal.com]

Shhhh although it's quite obvious who is who...

[katstevens.livejournal.com]

*reads Wikipedia entry*

I see. So basically, thermodynamics can do what the hell it likes as long as you don't try and measure/observe it?

[boyofbadgers.livejournal.com]

We-ll, it was more that this was a potential hole in thermodynamics. If such a creature existed then we could increase the overall entropy of the universe by employing it as a sorter of molecules by temperature. There isn't *really* a Maxwell's demon as described - any devices that appear to magically sort molecules in such a way do so in a manner that proportionally increases entropy elsewhere.

[katstevens.livejournal.com]

So: if thermodynamical theory is RIGHT then said demons CANNOT EXIST? And bcos there aren't any demons about at the moment then thermodynamics works just dandy?

[boyofbadgers.livejournal.com]

Basically, yes.

[katstevens.livejournal.com]

Hurrah! Kat in understanding SKIENCE shocker!

[burkesworks.livejournal.com]

I like Marna's answer best. Schroedinger's cat would take Maxwell's demon any time.

[marnameow.livejournal.com]

Although please be noting that while I approve of imaginary cats in boxes, I deeply disapprove of them being dead 50% of the time.

[burkesworks.livejournal.com]

Ah, but Schroedinger's cat was an imaginary cat! No real cats were harmed by old Erwin during the course of his experiments.

[marnameow.livejournal.com]

I don't care that the cat's imaginary. My head is full of imaginary cats and I don't let anyone hurt them.

[ciphergoth.livejournal.com]

Just read the Wikipedia entry (http://en.wikipedia.org/wiki/Maxwell's_demon). I wasn't far off, but I wasn't right either...

[dubdobdee.livejournal.com]

only a scientist would think that SORTING wasn't work < / pynchon and the admin staff >

[boyofbadgers.livejournal.com]

That's what I said when I first came across it! It was pointed out to me that the mode of sorting is one where the sorting things do the work, you just have to yay or nay them. Opening and closing the door does require energy expenditure, yes, but it's fairly easy to imagine a (very high temperature) situation where this is negligible compared to the potential variation in molecule speeds. FWIW, my gut feel is that Szilard is absolutely right wrt the measurement thing, whereas the information loss explanation is k-lame.

[the-roofdog.livejournal.com]

whereas the information loss explanation is k-lame.

I thought the same thing. All the "storage space" argument means is that you couldn't keep on decreasing entropy for an infinite amount of time, surely ? Well I don't want to, I'd be happy enough disobeying the laws of thermodynamics for just a mischievous hour or so, thanks ta.

[jauntyalan.livejournal.com]

information loss thing is KEY! in knowing all about the molecules you have to make a device that remembers it all. either you know a lot, and energy is recoverable, or you know next to nothing and it isn't.

In which I think out loud

[boyofbadgers.livejournal.com]

Right, OK, except that the entropy change due loss of information is not necessarily equal to the potential gain in entropy of the entire system. That's before you even start thinking about what you need to know about the individual molecules. You don't need its exact velocity, just that it is higher or lower than the mean. And this information is preserved by the very act of sorting. Of course, you need to determine the mean, but this can be achieved to enough accuracy by sampling the precise velocity of a relatively small number of molecules. So actual information loss is ONLY that of the precise velocity of those molecules, which if small enough is easily storable anyway.

Of course, now I think about this, I really want to do some actual calculations. It does occur to me that the less accurate the mean the less likely any gains in entropy are to be made, and that these might cancel out nicely.

[boyofbadgers.livejournal.com]

Of course, this assumes thermodynamic entropy is directly equivalent and translatable into informational entropy and vice versa.

[jauntyalan.livejournal.com]

i've got a really good book about this somewhere with a really persuasive handwaving explanation :-)

[boyofbadgers.livejournal.com]

Heh, I used to know a lot more about this. I was never quite convinced that they were the same thing tho. It seems obv and intuitive that yr stat-mech entropy can be used a type of measurement of the information that is held in a simple physical system in which the informational units are co-incident with the discrete energy levels of the components of the system. However, reversing it such that X amount of info automatically equals X amount of thermodynamic entropy seems less straightforward.

[catsgomiaow.livejournal.com]

So, it's just me and steviespitfire that immediately thought of Big Brother, then? ;)

[steviespitfire.livejournal.com]

Haha, spooky!

Though she's more of a harpy, eh?

[hotbeatz.livejournal.com]

[beckyc.livejournal.com]

It seems that you really don't know many physicists (or not many nonsilent ones anyway), do you? How did that happen?! I'd have thought loads of people would have done it to A level at least.

[boyofbadgers.livejournal.com]

The poll was more an attempt to discover how many non-physicsy people had heard of JCM, and whether this was due to t'Demon. Much to my surprise, more people have heard of the man himself than of his demon.

[friend-of-tofu.livejournal.com]

You meanie! I got all excited thinking there was some sort of 'Velvet Goldmine' connection and expecting something involving drugs, bisexuality and really silly platform boots. And it's just something about science! *huffs* I've had enough of science this week, as I already said re: the maths/science debate. Science is naughty. And not shiny enough.

(PS Next week I might think it's terribly exciting tho)