[Comic title: Delta-P; alt text: If you fire a Portal gun through the door of the wardrobe, space and time knot together, which leads to a frustrated Aslan trying to impart Christian morality to the Space sphere.]
There's nothing I can say of XKCD's various artistic failures which hasn't been said millions of times already. So, let's criticize Randy's most valued thing in the world: his precious science, his physics, or more precisely his grasp of fluid mechanics(breast milk not included- let's leave that one to Rob). [Nice. -Ed.]
Now, I'm an undergraduate of physics. I took a course of fluid mechanics with one of the world's premier physicists. I only mention this to stress that when I say I had no idea how the fuck Randall got the formula he uses in this one, I know what I'm talking about. But, eventually, I found out the horrible truth:
Randall begins with Q=A*v, which says that the flow equals the area of opening times the speed of the water relative to the wardrobe. This is wrong, but compared with his future follies this is actually still pretty acceptable. Only now Randy needs to calculate that speed, and here he fails tremendously.
Randy assumes conservation of energy, which is usually a fine thing to assume when doing physics. He takes the initial, purely potential energy of the wardrobe as Ei=mgd .He takes the final, purely kinetic energy as Ef=1/2 mv^2 .Because he assumes conservation of energy, both quantities are equal and so he extracts v from that and finally gets Q=A*√(2gd).
Now, his whole process is rife with errors(the Q=A*v thing assumes both laminar flow and and an opening that is two-dimensional, none of which occur here,) but let's narrow it down to just two of the most obscene ones:
- There is no conservation of energy here, you dumb fuck. Friction with water is a substantial, non-conservative force which does not allow you to use even actual fluid mechanics stuff such as Bernoulli's principle, let alone the high-school-level conservation-of-energy calculations shown above which Randy tries to pass off as science. If this was true, it could lead to all sorts of shit: a cylinder that is moving in such a liquid as Randall suggests would never come to a stop or even slow down, which is obviously a nonsensical result. This is what was known historically as Stokes' Paradox, this is why the concept of viscosity was introduced, and to top it off, this was all well known for 150 years or so. Do try and keep up, Randy. This would be okay, though, had Randy tried to find the speed of the wardrobe as it hit the water, but
- Randy doesn't know how to use the concept of potential energy. This is some really elementary stuff. This is high-school level stuff, and Randy fails at it miserably. Randy tries to calculate the wardrobe's speed on the moment of impact with the water. He takes the potential energy as mgd, when d is the ocean depth. . To find the speed of impact he should take the height of the wardrobe relative to the sea level, and what he takes is the height of the wardrobe relative to the ocean floor. Therefore, the speed he would extract using the method shown above is not the speed of the wardrobe upon impact. What he gets is the speed of the wardrobe when it reaches depth d under the sea level, and even that is assuming friction with water is just as negligible as friction with air. This gives him a nonsensical result: Randy says that the deeper the ocean is, the more water would flow into the wardrobe- as d grows, so does the root of d. At the limit where the ocean depth approaches infinity, an infinite amount of water would flow into the wardrobe as soon as it hits the water. This is hideously, preposterously wrong. I really cannot stress out just how asinine this error is. No wonder this guy was kicked out of NASA.
Now, a real physicist would've said 'gee, this result is ridiculous, I'd better check out where I've gone wrong.' What Randy said was 'gee, this result is ridiculous, I'd better publish it.'
first!
ReplyDeleteDespite the picture, isn't the math talking about the wardrobe when it's actually AT the bottom of the ocean? Seems to solve #2. Dunno about #1, I hate napkin-mathing friction.
ReplyDeleteit's not supposed to be right it's supposed to LOOK LIKE MATH
ReplyDeleteif you want it to be right you're not the target audience
He's saying the witch didn't know what hit her, anon 7:28. The wardrobe would take a while to get there.
ReplyDeleteYeah- the speed of the waterflow is talking about the flow out if you could open a 'portal', in this case the warddrobe, to drain the ocean at its bottom. He's not suggesting that it's the descent of the warddrobe itself that's pushing the water into narnia, or else it would be falling open-face down in the illustration.
ReplyDeleteToricelli's theorem says that when the opening of a 'tank' is much less than the surface area exposed to air, the velocity of the flow out is equal to root(2gh), where h is the hight of the fluid above the opening.
Obviously there's certain assumptions- back of the napkin calculations rarely muck about with friction and viscosity and the like- but I'm pretty sure you'd be making just as much fun of him if he'd done seriously number crunching when the primary conceit is a Magical Wardrobe.
It's a very slightly amusing approach that would have taken a lot less than however many young adult fantasy novels, at any rate.
I don't know anything about physics, but according to wikipedia toricelli's law is based on bernoulli's principle and Rob said it does'nt apply here
ReplyDeleteno i didn't
ReplyDeleteit's just a webcomic dude, not a scientific journal, loosen the fuck up
ReplyDeleteYou complete idiot, Elly. You call yourself a physics undergrad? YOU HAVE BESMIRCHED THE GOOD NAME OF XKCD SUCKS WITH YOUR INACCURATE REVIEW. OUR 100% RECORD OF CORRECTLY POINTING OUT THE FLAWS IN EACH COMIC IS GONE! GONE FOREVER!
ReplyDeleteGuest reviewer Elly, who was the one who that said Bernoulli's principle doesn't apply- was referring to what she thought Randy was calculating, which was the speed of the water entering the warddrobe forced in from its decent to the bottom. You'll see she talks alot about the speed of the wardrobe- which doesn't really apply once it hits bottom.
ReplyDeleteFrom that perspective, the drag and viscosity neglected in bernoulli's equations become very important and would be a truly grevious error. One can imagine a falling wardrobe, magical or not, would slow down somewhat upon impact with the surface of the water.
However, once we get to the bottom, as I believe Randy intended to estimate, the sins are less grevious. Seeing as he used the 'approximate' squiggles I think we can let the viscosity/friction on the inner surface of the wardrobe, the fact that the flow on the inner surface would tear any wooden furniture apart, and the fact that there's no such thing as Narnia, slide. It's an utterly forgettable comic with no greivous errors beyond those abstractions used in any basic physics course.
Ella = Anachronistic = Legion of Kittens = Rob
ReplyDeleteRandall, quit the asspaincockishly autismic samefagging
I'm fairly certain that Torricelli only applies for small Reynolds numbers; the number here is roughly 10^8.
ReplyDelete(assuming v=sqrt... which assumes Torricelli, so I assume Torricelli is out of the question)
ReplyDeletecaptcha: scism. Hey, that's almost a real word!
http://i.imgur.com/c5KQa.png
ReplyDeleteThe anchor
ReplyDeleteis keeping it at the bottom
while all this happens.
DO NOT MAKE RANDALL RIGHT AGAIN
As someone who stopped taking physics after grade 11, all I can say is "NASA didn't fire him, they were more subtle -- they just didn't take him on (again) after the internship ended."
ReplyDeleteI'm not defending Randy's math skills here, I'm just defending NASA's tact when dealing with the less capable.
God bless NASA, kings among men.
The anchor is only there to make sure it falls down from wherever it was pushed.
ReplyDeleteRandall DID forget the difference in time-flow or what-not beetween earth and narnia. Or that the wardrobe was only a portal sometimes. Regardless of scientific integrity, he still sacrificed accuracy for the sake of a "joke".
ReplyDeleteyeah my review of the comic, had i written one, would have noted that the portal didn't work when people were trying to find it. deliberately sinking it to fill it with water probably counts as deliberately looking for it
ReplyDeleteWHAT THE. BAD REVIEW. THE DEPTH LETTER IS REFERRING TO THE DIFFERENCE IN PRESSURE BETWEEN THE AIR AND THE BOTTOM OF THE OCEAN THIS IS WHY THE COMIC IS CALLED "DELTA-P". THERE IS NO POTENTIAL VELOCITY THIS IS TERRIBLE TERRIBLE UNDERGRAD PHYSICS GET OUT.
ReplyDeleteCan we all agree on at least one point?
ReplyDeleteIt's amazing that Randy was able to even draw this comic, because normally he's got both hands firmly wrapped around goat cocks.
The little freak makes Mr. Hands look like Mr. Rogers.
And another thing - did the bastard ever fix his bowl cut? Seems like the kinda guy who's gonna go off the deep end & shave his head when things really go south.
Wow... Randall got fucking RIPPED APART
ReplyDeleteIs this review going to remain posted? The author obviously misunderstood what the comic was suggesting. You're supposed to assume the wardrobe sinks to the bottom of the ocean and it's the DELTA P (title) that's going to cause the high flow rate. While the equation's derivation may be unrealistically derived from ideal situations, the bulk of your rant about the velocity at which the wardrobe strikes the ocean, is moot.
ReplyDeleteRob i don't know about the wardrobe but in The Silver Chair the kids just wish they were in Narnia and *boom*. Wasn't the idea that aslan (the lord jesus christ) could do whatever the fuck he wanted and his own laws didn't bind him (like the lord jesus christ)? So if aslan wanted this to work then it would.
ReplyDeletePhysics is therefore useless.
Randall's derivation IS flat out wrong(as Reynolds guy at 8:46 has shown), but so is the reviewer's interpretation of the comic.
ReplyDeleteAnchors aren't designed to pull things under water... that's why they are hook shaped.
ReplyDeleteI've only read the books once through and seen the BBC and new Hollywood versions once... but it was always my impression that the pathway to Narnia only existed when the door was closed so this wouldn't work for that reason too... and finally, assuming that Narnia is at least pretty big the guy who does this stunt no only robs the world of it's oceans but kills he entire population of Narnia, along with the White queen... you know, providing she doesn't use magic to freeze the incoming deluge unless the resulting jet is somehow pointed right at her castle. and I'm not expert or whatever but wouldn't water travelling at that speed be super heated by friction with the air and become steam and dissipate?
So, do you guys think megan is real? I mean, obviously she is, but do you think her name is really megan?
ReplyDeleteIs she aware of what xkcd dude is writing about her for everyone to see?
Why did he not mention her recently?
Is it because she got a restraining order against him after he drew an elaborate close-up of her vagoo?
This is important.
if we assume the comic is talking about the velocity after the wardrobe has reached the bottom... it STILL doesnt make any fucking sense.
ReplyDeletefor a start, you'd get water flowing through as it sank, starting as a puddle, and increasing in velocity - so if she was nearby, she'd see it building in speed, and if she wasnt it wouldnt matter anyway.
what is there to keep the wardrobe doors open? personally i'd have torn those off already.
what stops the wardrobe from landing upside down?
what evidence has there ever been that the wardrobe is actually a *portal* rather than a teleporter? (and yeah, as pointed out, its all just a load of religious shite anyway, so why assume that science would apply at all?)
a better version of the same comic wouldve been something like:
"Portal-Gun based weapon #417"
with a picture of a portal pointing at someone in one frame, and someone pointing the portal gun at the ocean in another.
it could have still had the maths at the bottom.
that would still have been fairly shitty, but wouldve been better than this...
So, is the Chronicles of Narnia any good? I never got a chance to read it.
ReplyDeleteOMG, I just had a really confusing lecture in fluid dynamics today. Elly, get out of my head!
ReplyDeleteIf someone has already mentioned this then ignore me, but no one has take into account the difference in time speeds between here and Narnia, time moves faster in Narnia than it does here e.g. the children aged quicker there than here. Surely that would mean the water would come out at a significantly slower rate than it went in and wouldn't be that spectacular
ReplyDelete@ goatkcd 969:
ReplyDeleteFuckin' fantastic
No, you don't have to close the wardrobe door. The book specifies that they leave it open a crack, prob to stop seven-year-old readers getting locked in wardrobes I imagine..
ReplyDeleteExcellent point about time flow difference Anon@5:24 AM... you are right, they spend YEARS in Narnia and only moments pass in the real world (actually their world seems to freeze up when no one from our world is observing it when this is convenient for the author).
ReplyDelete@anon518: Just skip to "The Silver Chair", mostly because the Christian allegory in it is so obscure as to be almost meaningless. If you want to read 2-5, or 7, just read the Children's Illustrated Bible, or Revelations specifically.
ReplyDeleteThat said I also thought the Magician's Nephew was pretty rad, but I think I was 13 when I last read it so who knows how that has aged.
We shall destroy this wardrobe, whatever the cost may be.
ReplyDeletei think randall shuld get OUT OF THE CLOSET xD xD
ReplyDeleteVoyage of the Dawn Treader has a painting of a boat on the sea as the portal to Narnia. Water comes through to our world (at least in the movie, been a long time since I read the book).
ReplyDeleteSo,
a) there's already been a portal moving water between Narnia and here
and
b) as others have pointed out, the portals close up when not actively transporting children
@ 7:56
ReplyDeleteb) is a great point. I think the portals are pedophiles and Narnia is a rape dungeon.
And the one thing that Elly didn't touch is that, as a joke, it's not that bad. Probably old and overused, but the joke itself isn't horrible at all.
ReplyDeleteThen there's that she got her perception of physics wrong...please bring Rob back. I'd take his stupid milk jokes rather than horrible reviewing.
@ the "it will wipe out the rest of narnia with the queen" comments
ReplyDeleteDon't forget about our ocean life and vast shipping infrastructure :3
Dear Rob.
ReplyDeleteYou are obviously the most pitiful and pathetic person ever to live on this planet. I can only imagine how much hatred, lonlyness, boredom (or whatever it is, that makes you do this) one needs to build up, before he actually devotes his life to pointing out the errors in an insignificant webcomic.
I honestly hope, that you find peace some day.
cheers
Terrible review! Torricelli rulez!
ReplyDeleteBy the way it seems to me that our dear Elly is a Randall-wannabe.
"I took a course of fluid mechanics with one of the world's premier physicists. I only mention this to stress that when I say I had no idea how the fuck Randall got the formula he uses in this one, I know what I'm talking about."
that sounds like "i'm smarter than you, let me show how", and fails miserably.
P.s.
I wonder which world premier physicist is giving an undergrad fluid mechanics course...
Torricelli's law doesn't apply here dude. Reynolds number's way too big.
ReplyDeleteAnon5:24 is the only relevant criticism of the magic-science in this comic.
ReplyDeleteAnd the original reviewer needs to post an apology. The first fucking hour of any course involving any sort of fluid mechanics probably gets students to think about water going down a plughole, and anyone who cannot solve it is well down the path to failing the course. (And anyone who doubts that Torricelli is applicable might want to derive the whole formula from first principles. Handwaving fancy nomenclature like "Reynolds number!" makes you sound like you've just memorised random rules for an exam and you don't know what you're really doing.)
Randy is clearly not NASA material but he is slightly brighter than the banana posting this review. He has a freshman grasp of physics and a fairly good grasp of social engineering, having gained a niche Charismatic Leader role.
I feel as if this review shows that this blog doesn't always understand XKCD, I first read your reviews three comics ago and was curious when the first time that would happen is, I actually gave you guys like a month since you know they're not that complicated to understand. Don't know how the reviewer is but I wasn't an undergraduate physics major but even I understood what the comic was suggesting, the only reason to have depth of the ocean on their is to imply the portal was at the bottom. I have now decided that xkcdsucks sucks way worse than xkcd, because at least I'm entertained by xkcd.
ReplyDeletePeople scrutinizing the interpretation of the reviewer should instead scrutinize why Randy had to pick such a confusingly irrelevant quantity to support his conclusion. Flow rate at the bottom of the ocean? Wouldn't you assume Narnia would already be flooded by that point anyway? Also, inclusion of water jet velocity is completely irrelevant if bottom-of-the-ocean flow actually was what he was after. Why include that?
ReplyDeleteDon't you see why there might have been room for misinterpretation? This isn't the reviewer not "getting it", it's Randy being piss-poor about the clarity and relevance of his presentation.
Also, even if his point is clear and sound, it doesn't change the fact that this "comic" is just stupid. "Numbers and a Narnia reference? Better lol".
This comment has been removed by the author.
ReplyDeleteI think it's just "let's flood Narnia" and "over-thinking bait." So.
ReplyDeleteI'm willing to let the reviewer get off with being only halfway retarded, since both picture and text seem to be referring to a momentary splash of some sorts. I haven't read Narnia so I can't talk about how close the witch is to the portal, but I'm with 6:41 here-the wardrobe wouldn't reach a depth of 2km without anyone noticing it over at Narnia already.
ReplyDeleteWhy not just draw the wardrobe at the bottom of the ocean, anyway? That would leave no room for such dumbfuckery in the first place.
Why does Marion Delautist always delete and reupload every single one of his fucking post? Is he just an aspergoid looking for attention? More at 10:00.
ReplyDelete@Jefferson suck my cock.
ReplyDelete@Everyone else Anyone noticed how unnecessary that forumla is to the comic?
I used to visit this place since about a month after it started. And I mist say, with no Carl, this place has gone to shit. More so the quality of people who comment here. I read through some comments of a review for a comic about 2 months ago and one you sick fucks wrote a weird creepy fan fiction of Randall masturbating to women's rights blogs or some shit. You can say what you want to about Randall, but I'd rather read his mediocre web comic and move on with my day rather than furiously type a short story of someone I hate masturbating.
ReplyDelete...said LosingFaithInHumanity, as he furiously took Randall's full girth.
ReplyDelete@LosingFaithInHumanity
ReplyDeleteThat guy's name was XKCD Fan. He didn't hate Randall, he just liked writing about him.
This reviewer is clearly an xkcd fan trying to bring the blog into disrepute by writing a really wrong review.
ReplyDeleteHe gave himself away by actually making an effort.
For future reference, this is how Rob does it:
Comic x: This was shit.
Comic x+1: This was shit too. Megan's nipples.
Seething hatred follows in the comments, the only reason anyone's really here.
you guys are nerds
ReplyDeletehello all, forgive me if this has come up already
ReplyDeletesetting most of the fluid dynamics equations aside, there's 2 main elements concerning pressure here that the comic has not addressed.
1) we must assume that based on most of the books and movies, that the wardrobe must initially be closed for it to open the portal(whether you're looking for it or not.) that being said the wardrobe would need to be closed then for the portal to open on the bottom somehow for all the water to pass through, problem with that is if there were any air in there upon submerging the depth pressure would instantly destroy the wardrobe making it all moot
2)even if the wardrobe is open and randal's assumption of how the physics were magically true, there's a second problem in the fact that even though the maps very quite a bit about the layout and some of the geography of narnia, they all agree that the witch's castle is in the mountains to the north of where the lamppost and portal into narnia is. therefore at best due to equalizing pressure, putting the wardrobe at the bottom of a large body of water would do would be to create a new lake for the white queen witch whatever to go boating on over the now submerged homes of any nearby woodland creatures.
Wouldn't the white queen WANT more water anyway? After all, more water = more ice = more subdugation, bitches.
ReplyDeleteI ACTUALLY THOUGHT THE NEW COMIC (ABOUT THE E-MAIL) WAS FUNNY AND I WILL CONTINUE TO THINK SO UNTIL ROB HAS PROVED ME WRONG
ReplyDeleteWhoa, 970 is a complete and utter shitcake
ReplyDeleteAt least 969 -tried- to baffle the lowly unwashed masses with bullshit math equations
970 is another of a long list of xkcd comics that remind me of your average sitcom: The situation would be amusing if it happened in real life, but when you know some writer sat for two days to contrive it, it's not that funny.
ReplyDeleteEvery single post on this blog is by the same person.
ReplyDeleteDear Rob.
ReplyDeleteYou are obviously the most pitiful and pathetic person ever to live on this planet. I can only imagine how much hatred, lonlyness, boredom (or whatever it is, that makes you do this) one needs to build up, before he actually devotes his life to pointing out the errors in an insignificant webcomic.
I really like the assumptions made in this comment. Really.
I know. Rob doesn't have a life. How could he devote one to anything?
ReplyDeleteThis is like a full time job, it's a wonder he stays employed while finding the time to post other people's reviews and 100-word reviews when that falls through. Rob: basically superman, if superman hated a stick-figure web comic.
ReplyDeletehahah, that green hat guy is so wacky!!
ReplyDeleteDue to Rob's extreme obeseness and slothfulness, it actually does take him a shitload of time to write these posts. Do you even realize how hard is it to hit the right key with his fat, thick, greasy fingers?
ReplyDeleteok i'm just gonna come out and ask, how do the little ponies have such intricately styled hair without opposable thumbs?
ReplyDeletethe ass tattoos are sexy though, i would lick that anytime
Re: Anon@10:37 AM
ReplyDeleteUnicorn Pony's have telekinesis to do their hair... I assume they do the other ponies hair for them too.
Guys, guys, guys, guys, GUYZ!
ReplyDeleteWe're missing the important thing here, Randy is drying to drown Aslan. What the fuck?
He is literally worse than Hitler.
The actual comic for the recent xkcd would be somewhat amusing, but he tarnishes the minor victory by making out to be mocking a real phenomenon with the title and alt-text. 'sif that would happen.
ReplyDelete^ Rob, that's the entire text for my guest review for 970. Please publish it. My real name is Phillip McArson.
ReplyDelete970 is a little contrived but kinda funny
ReplyDeletethe alt text is explain the joke trash but it almost always is so
Yeah, I agree, 970 is kinda funny.
ReplyDeleteI didn't lol, but anyway, it was funny.
I hope Rob will take that into acount.
To me it looks like he's trying to do a simple pressure-head/flow calculation if the coffin is 2km below the surface of the ocean. The ocean would be applying 2000m of hydraulic head on the opening. But the artwork doesn't show that, I actually had no idea what this comic was about until I read xkcdsucks because its confusing as fuck.
ReplyDeleteI'm confused by the direction this review took. Does it matter if the equation made sense or not?
ReplyDeleteThis misses the mindboggling phenomenon that occurred in this comic: Randy did not think people would get the joke unless there was a complicated equation about fluid mechanics involved. What a bizarre, almost inhumanly perfect combination of insulting your audience's intelligence and also pandering to intellectual arrogance. I am astounded. This comic has been sticking in my brain and causing me to reconsider the nature of humanity.
Did it affect anyone else the same way?
Oh please, this is quite overanalysing.
ReplyDeleteYhis kind of very simplified calculations are actually pretty fun to derive, at our college we do the same thing from time to time. (like in a dead moment calculating how long it will take on average before a plain goes over your head, or how much Lychees would be needed to fill the entire university (we got a system called bami lectures, consisting of a lecture at midday about something cool while eating chinese food, and we always got these cans of lychees who noone eats, so yeah)).
It's just the fun of calculating something slightly ridiculous :)
The comic is unfunny and nowhere near as clever as its legion of fanboys think it is. So is the review. I thought you were meant to be claiming some sort of high ground, here?
ReplyDelete"There is no conservation of energy here, you dumb fuck"
ReplyDeleteWould you tell him that to his face?
R.
Hey Elly, its time to either 1) Pay attention to the said prominent physicist - or 2) Get your money back for your undergrad courses, because someone was/is lying to you ... to quote you "you dumb fuck" ...
ReplyDelete*Polite cough*
ReplyDeleteAny water flowing through doors would more than likely close them...
Discuss.
Well, if you go by the theory that "Randall is always trying to be funny", I think I ought to invoke William Shakespeare's famous quote:
ReplyDelete"Brevity is the soul of wit."
So, if you want to be funny, which is the better option? Using a simplistic and easily recognizable equation to get a rough estimate of what your absurd hypothetical situation might be like (with is actually what engineers do with real technical problems when they want to get a rough estimate of what they're up against), or as Elly suggested, write a Goddamn dissertation to get your flow physics exactly correct?
Here's a hint: Most people don't think a joke is funny if you have to spend ten hours explaining it.
xkcd is utterly mediocre, I concede, but this post just exemplifies the fact that people on here are prone to completely missing the joke of xkcd comics (shit or not) and end up making an asshat out of themselves.
ReplyDeleteYes, the post has more mistakes than the comic, yet they put it in here. Didn't you have a real, valid complain about it?
ReplyDeleteTch.
Wow... you all should get out more. It's a big beautiful world, go explore it.
ReplyDeleteRob, you make a total ass of yourself as you don't understand that the wardrobe is at the bottom of the ocean, "you dumb fuck."
ReplyDeleteThe reference to Narnia here is presumably based around the LionWitchWardrobe era, where the White Witch (Queen?) is ruling over the kingdom with a perpetual winter. It's always freezing, but never Christmas.
ReplyDeleteIf I remember rightly, the White Witch actually rules from her fortress north of Narnia. By some accounts, this region is mountainous.... and therefore going to be one of the last places to be hit by the deluge of water. The White Witch will basically be the last inhabitant of Narnia affected!
Speaking of the deluge of water.... what's also overlooked by the comic is the fact the region around the wardrobe within Narnia is, in fact, a dense forest. Even if there were a great spurt of water its momentum would just break on hitting the trees. Again, soaking some tree nymphs or something.
Also, forgive my total lack of science knowledge here (this might be totally wrong) but..... even if the Earth ocean *did* tumble through into the Narnian ocean, how much higher would the water level ACTUALLY rise? Because wouldn't it reach a kind of equilibrium once the water level reaches the top of the wardrobe?
And lastly, Narnia has a coastline, so when the water from the Earth ocean hits the Narnian ocean, what then? Nothing. That's what.
tl;dr- this is a useless attempt to assassinate the White Witch, as the only way she'd possibly be pwned by this is if she just happens to be strolling in front of the wardrobe door at the time. It's a bit like giving Robert Mugabe a bunch of papers to sign in the hope he'll eventually give himself a papercut on his jugular.
Dissecting xkcd logic = serious business, doncha know >;D