The Pauli Exclusion Principle

ETA: Since this is my most popular page ever, how about I skip the sci-fi and jump straight for what you came looking for?

The Pauli Exclusion Principle simply states that a fermion cannot exist twice in a quantum state.  At a more basic level (also known as, the level I’m at and I’m a fifth year chemistry student), two electrons with the same spin cannot be in the same quantum state.   They have to be of opposite spins.

Pauli Exclusion Principle Example

Figure 1 is hydrogen. Yeah, it’s pretty boring.  One electron in the 1s orbital.  That electron could be pointing up or down (ie, of either spin), but by convention we write it upwards.

Figure 2 is helium… sort of.  In this example, two electrons are in the 1s orbital.  However, both electrons have the same spin.  That is what the Pauli Exclusion Principle says we cannot do.

Figure 3 is also helium.  Two electrons in the 1s orbital however, the second is pointing downwards, thus signifying a spin in the other direction.  That is the correct way of drawing the 1s orbital.

(The electrons can also be drawn on top of the line.  In fact, I had one chem prof who wanted them drawn that way and a different chem prof who wanted them to be drawn through the line.  Clearly, I like the second chem prof more.)

Now, back to the regularly scheduled tv discussion.

 

Last Thursday, Fringe made a grave mistake in science.

Yes, Fringe is all about mistakes in (fake) science.

This mistake, however, holds the singular claim (for this show) of pissing me off.

The mistake?  Nina Sharp was explaining to Olivia about why the two universes cannot be brought together – one will inevitably be destroyed.

Yes, that’s a pretty common theory and it always shows up in science fiction.  In fact, I have absolutely no problem with that – it’s effing theoretical physics so do whatever the hell you want.

Just don’t mutilate quantum mechanics whilst you do so.

You see, Nina’s reasoning for why two universes can’t exist at the same time was ‘you know the Pauli Exclusion Principle?’ and then smush the two snow globes together and one breaks whilst the other is perfectly intact.  Immediately, I hit the pause button on my dvr and yelled at the tv ‘but that’s not what the Pauli Exclusion Principle says!’  I also wished that I was watching this live so I could get on the twitters and tweet about it, but my twitter addiction is not the topic of today’s blog.

While the wiki article on the Pauli Exclusion Principle is pretty technical and could almost imply that two of the same things cannot exist at the same time, you do have to remember that things on the quantum level do not apply to the macroscopic world.  Last I checked, my location wasn’t uncertain.  I’m really damn sure that I’m sitting in front of my computer writing this blog entry.  However, that electron?  Yeah, that one over there.  Well, it might not actually BE over there.  It could be here.  Or there.

And somehow I got onto Heisenberg’s Uncertainty Principle and the Born Interpretation instead of the Pauli Exclusion Principle.

Right.

Well, I am in a class about quantum mechanics right now.

The Pauli Exclusion Principle simply states that a fermion cannot exist twice in a quantum state.  More generally, two electrons with the same spin cannot be in the same quantum state.   They have to be of opposite spins.

Pauli Exclusion Principle Example

Figure 1 is hydrogen. Yeah, it’s pretty boring.  One electron in the 1s orbital.  That electron could be pointing up or down (ie, of either spin), but by convention we write it upwards.

Figure 2 is helium… sort of.  In this example, two electrons are in the 1s orbital.  However, both electrons have the same spin.  That is what the Pauli Exclusion Principle says we cannot do.

Figure 3 is also helium.  Two electrons in the 1s orbital however, the second is pointing downwards, thus signifying a spin in the other direction.  That is the correct way of drawing the 1s orbital.

(The electrons can also be drawn on top of the line.  In fact, I had one chem prof who wanted them drawn that way and a different chem prof who wanted them to be drawn through the line.  Clearly, I like the second chem prof more.)

So, yeah, absolutely nothing to do with two universes colliding.

Great job on the science there Fringe.  Great job.

At least Stargate made up a nonsense reason for why two people from different universes can’t exist in one universe at the same time.  Entropic Cascade Failure ftw!

Long story short?  If you’re going to make up science, make up science.  Don’t try to manipulate actual scientific principles to suit your own needs.

  • http://www.monoclelad.com monoclelad

    I'll be honest, I have no idea what you are talking about, and your charts don't actually help me understand. :/ But I guess thats why my intrest in science tends to end at the macro level before you get into the nitty gritty details.

    Which is why all my knoweledge of quantum physics is a futurama joke “Cheaters! you changed the outcome by measuring it!” and of course Schrödinger's cat.

    So rather then derail us back into the same argument we were having before… I will simply say I agree with you, that they shouldn't butcher real science and should just make it up if they are so determined to make there world work that way. Of course I think theres simply to much explaining of the science in scifi stories anyways, real or not. Its so dreadfully boring and forced. Thats why I can't get into star trek, its like 40% really interesting investigations of culture and the meaning of humanity, and 60% people making things up to sound cool and futuristic.

    But that could just be because I enjoy writing for comics and the first rule of comics is that every word that doesnt add to the page subtracts.

  • http://anovelconcept.net aethre

    It helps if you know about orbitals first. And quantum numbers.

    Classical science bores me – nothing interesting happens! Give me the weirdness of quantum mechanics!

    As for Star Trek… I like their pseudo-science. Half of it is utterly ridiculous as well and it's pretty fun to laugh at. As for cultures… half the time I find them done rather ham handed so, yeah, bleh.

  • http://www.monoclelad.com monoclelad

    Well thats because most episodes of star trek are awful and ham handedly written, in both the psuedoscience and the story. The episodes I walked away from enjoying though had nothing to do with the science, its always the stories premise, or some of the character moments.

    I always feel like the science just gets in the way personally. maybe if it was real science then it would be more interesting, but I can't really know for sure until I've seen it done well (I encourage you to explore that in Chrono Loran.)

    Though SMBC did a really great comic that did hinge on the science to make the punchline work, so I guess it can be done… its pretty rare though. http://www.smbc-comics.com/index.php?db=comics&

  • http://anovelconcept.net aethre

    XD That is a brilliant comic, XD

    Ah, but science jokes are niche jokes. Anyone who isn't in the niche isn't going to like them. I can't read Penny Arcade for that reason, for example. I can't read any gaming comic, to tell you the truth.

  • http://www.monoclelad.com monoclelad

    I'll be honest, I have no idea what you are talking about, and your charts don't actually help me understand. :/ But I guess thats why my intrest in science tends to end at the macro level before you get into the nitty gritty details.

    Which is why all my knoweledge of quantum physics is a futurama joke “Cheaters! you changed the outcome by measuring it!” and of course Schrödinger's cat.

    So rather then derail us back into the same argument we were having before… I will simply say I agree with you, that they shouldn't butcher real science and should just make it up if they are so determined to make there world work that way. Of course I think theres simply to much explaining of the science in scifi stories anyways, real or not. Its so dreadfully boring and forced. Thats why I can't get into star trek, its like 40% really interesting investigations of culture and the meaning of humanity, and 60% people making things up to sound cool and futuristic.

    But that could just be because I enjoy writing for comics and the first rule of comics is that every word that doesnt add to the page subtracts.

  • http://anovelconcept.net aethre

    It helps if you know about orbitals first. And quantum numbers.

    Classical science bores me – nothing interesting happens! Give me the weirdness of quantum mechanics!

    As for Star Trek… I like their pseudo-science. Half of it is utterly ridiculous as well and it's pretty fun to laugh at. As for cultures… half the time I find them done rather ham handed so, yeah, bleh.

  • http://www.monoclelad.com monoclelad

    Well thats because most episodes of star trek are awful and ham handedly written, in both the psuedoscience and the story. The episodes I walked away from enjoying though had nothing to do with the science, its always the stories premise, or some of the character moments.

    I always feel like the science just gets in the way personally. maybe if it was real science then it would be more interesting, but I can't really know for sure until I've seen it done well (I encourage you to explore that in Chrono Loran.)

    Though SMBC did a really great comic that did hinge on the science to make the punchline work, so I guess it can be done… its pretty rare though. http://www.smbc-comics.com/index.php?db=comics&

  • http://anovelconcept.net aethre

    XD That is a brilliant comic, XD

    Ah, but science jokes are niche jokes. Anyone who isn't in the niche isn't going to like them. I can't read Penny Arcade for that reason, for example. I can't read any gaming comic, to tell you the truth.

  • http://www.monoclelad.com monoclelad

    But PA is great cause of the essays, not the vaugely about gaming comics. XD

    I've thought about it more and I don't dislike science in tv on principle, because it was done very well in Numb3rs before they jumped the shark. The problem with it on most shows is its used as conversational filler, and is more like empty calories. Numb3rs had some meaty conversations about math theories early on, dunno what they do now, after a doughy old nerdy guy went to space I stopped caring.

  • http://anovelconcept.net aethre

    In other words, you just don't like technobabble. For me, it depends on the show. I love Stargate's technobabble because Sam and McKay make it awesome just because they're Sam and McKay (and because the show pokes fun at technobabble with every technobabble-y scene) but Star Trek often fails at it.

    I can't stand reading PA's essays either >.>;

  • http://www.monoclelad.com monoclelad

    I think chuck wins at the technobable, because its more used to reinforce who the characters are better. Its like yes if what they said meant anything, then those characters would say that to each other because they are huge nerds.

    Except the time chuck was drooling over some off the shelf dell servers. he would not drool over those no matter how big of a rack of them Castle had.

  • http://www.monoclelad.com monoclelad

    huh weird, I mention chuck and then I find on twitter that he's the #1 trending topic. C-c-crazy.

  • http://anovelconcept.net aethre

    Ooooh Chuck, XD

    And that's also, incidentally, why Stargate is good at techobabble. Sam TRIES to be short and concise but then she just HAS to elaborate on the really nifty science so Jack cuts her off. McKay, on the other hand, likes to make everything sound more difficult than it really is. It's just who they are.

  • http://www.monoclelad.com monoclelad

    yeah I have no specific problems with stargate's technobable, if only because jacks there to be like, yeah the science monsters did it, i'll pretend I understood the word formations coming out of your mouth so we can go back to killing stuff.

  • http://anovelconcept.net aethre

    Jack and Sam are awesome, XD Of course, poor Jack has to get the technobabble from both Sam and Danny, though I think he likes Sam's more.

  • http://www.monoclelad.com monoclelad

    But PA is great cause of the essays, not the vaugely about gaming comics. XD

    I've thought about it more and I don't dislike science in tv on principle, because it was done very well in Numb3rs before they jumped the shark. The problem with it on most shows is its used as conversational filler, and is more like empty calories. Numb3rs had some meaty conversations about math theories early on, dunno what they do now, after a doughy old nerdy guy went to space I stopped caring.

  • http://www.monoclelad.com monoclelad

    But PA is great cause of the essays, not the vaugely about gaming comics. XD

    I've thought about it more and I don't dislike science in tv on principle, because it was done very well in Numb3rs before they jumped the shark. The problem with it on most shows is its used as conversational filler, and is more like empty calories. Numb3rs had some meaty conversations about math theories early on, dunno what they do now, after a doughy old nerdy guy went to space I stopped caring.

  • http://anovelconcept.net aethre

    In other words, you just don't like technobabble. For me, it depends on the show. I love Stargate's technobabble because Sam and McKay make it awesome just because they're Sam and McKay (and because the show pokes fun at technobabble with every technobabble-y scene) but Star Trek often fails at it.

    I can't stand reading PA's essays either >.>;

  • http://anovelconcept.net aethre

    In other words, you just don't like technobabble. For me, it depends on the show. I love Stargate's technobabble because Sam and McKay make it awesome just because they're Sam and McKay (and because the show pokes fun at technobabble with every technobabble-y scene) but Star Trek often fails at it.

    I can't stand reading PA's essays either >.>;

  • http://www.monoclelad.com monoclelad

    I think chuck wins at the technobable, because its more used to reinforce who the characters are better. Its like yes if what they said meant anything, then those characters would say that to each other because they are huge nerds.

    Except the time chuck was drooling over some off the shelf dell servers. he would not drool over those no matter how big of a rack of them Castle had.

  • http://www.monoclelad.com monoclelad

    I think chuck wins at the technobable, because its more used to reinforce who the characters are better. Its like yes if what they said meant anything, then those characters would say that to each other because they are huge nerds.

    Except the time chuck was drooling over some off the shelf dell servers. he would not drool over those no matter how big of a rack of them Castle had.

  • http://www.monoclelad.com monoclelad

    huh weird, I mention chuck and then I find on twitter that he's the #1 trending topic. C-c-crazy.

  • http://www.monoclelad.com monoclelad

    huh weird, I mention chuck and then I find on twitter that he's the #1 trending topic. C-c-crazy.

  • http://anovelconcept.net aethre

    Ooooh Chuck, XD

    And that's also, incidentally, why Stargate is good at techobabble. Sam TRIES to be short and concise but then she just HAS to elaborate on the really nifty science so Jack cuts her off. McKay, on the other hand, likes to make everything sound more difficult than it really is. It's just who they are.

  • http://anovelconcept.net aethre

    Ooooh Chuck, XD

    And that's also, incidentally, why Stargate is good at techobabble. Sam TRIES to be short and concise but then she just HAS to elaborate on the really nifty science so Jack cuts her off. McKay, on the other hand, likes to make everything sound more difficult than it really is. It's just who they are.

  • http://www.monoclelad.com monoclelad

    yeah I have no specific problems with stargate's technobable, if only because jacks there to be like, yeah the science monsters did it, i'll pretend I understood the word formations coming out of your mouth so we can go back to killing stuff.

  • http://www.monoclelad.com monoclelad

    yeah I have no specific problems with stargate's technobable, if only because jacks there to be like, yeah the science monsters did it, i'll pretend I understood the word formations coming out of your mouth so we can go back to killing stuff.

  • http://anovelconcept.net aethre

    Jack and Sam are awesome, XD Of course, poor Jack has to get the technobabble from both Sam and Danny, though I think he likes Sam's more.

  • http://anovelconcept.net aethre

    Jack and Sam are awesome, XD Of course, poor Jack has to get the technobabble from both Sam and Danny, though I think he likes Sam's more.

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  • Fuckyou

    thank you sooooo much dude…. you are a beast

  • http://anovelconcept.net Nikki

    np! Love your fake email choice – I always approve of the word fuck. :3

  • Lmnewland

    You know, you’re actually pretty good at explaining things in a way that dumbasses such as myself can understand them. Ever thought about being a technical writer? Good money and you get to stay in your scientific field (not to mention travel).

  • Dfxgdxfg

    I came here after an xkcd comic referred to this concept indirectly…  seems too hard to understand so I’ll pass :p  Thanks for making this page for people who have more patience than I.

  • Lavender

    thx this really helps
    i was intrigued at the way u yelled at the tv
    if i there i would yell at it till it bursted
    thx again

  • Susan

    i have no idea wat ur saying
    how did this thing help u lavender?

  • Lavender

    hey i am lavender
    i see ur name is also lavender
    see this article would really help if u knew about the orbitals first
    and u have to know about quantum numbers
    this stuff is weird at first i didnt understand wat the heck this thing is talking about but when i read another article this sounds pretty easy
    know how to write electron configurations in notation form then this would be easy

  • Zkhirah

    Hay