Tuesday, April 23, 2013

XKCD What if?

By now I’ll assume that most (if not all) of you are familiar with the webcomic xkcd.  It is a comic about all sorts of things, and it is pretty funny and enjoyable, and I highly recommend it. 

But this posting isn’t about the comic, itself.  It is about the “what if” section of the xkcd website.  You see, Randall, the guy who writes the comic, is a person of certified galactic intellect and knows a thing or two about physics (you’ll understand why that is a massive understatement if you ever get hooked on “what if?” like I have).

Every Tuesday, he takes a question from the internet and answers it to best of his ability, and then “Mythbusters” it in awesome form, by taking the question and ramping it up to theoretical levels. 

For instance, when asked “what is the worst thing that can happen when using a pressure cooker?”Randall gives the standard answer:

Pressure cookers are dangerous.They can explode, in a sense, but not as violently as you might fear (or hope). The pressure inside a consumer cooker doesn’t go above about two atmospheres—about the pressure inside a can of soda. Those levels can be dangerous, but they’re generally not high enough to cause the metal to violently rupture.
So what makes a pressure cooker dangerous?Imagine a world where Pepsi is scalding hot. Now imagine that someone shakes up a can of Pepsi and sets it in front of you. That’s the real threat from a pressure cooker: If the seal fails (or the lid is opened too early), it can spray scalding stew in all directions.
But it’s not really an explosion

Then he gives the “Randall” version:

Of course, the question wasn’t about whether a pressure cooker is likely to explode. It was about what the worst thing that could happen was… for my money, one of the most horrifying things you could do is this:
(Note: Never try this, for reasons which will become obvious in a moment.)Fill the cooker with oxygen up to 5 PSI, then pump in fluorine until it starts escaping through the safety valve. Put the vessel over an open flame until it reaches 700°C (That’s °C, not °F. Yes, this will probably set off the smoke alarm.) Now, pump the hot gas over a liquid-oxygen-cooled stainless steel surface.The procedure here is a little tricky, but if you do things right, the gas will condense into dioxygen difluoride (O2F2).And that stuff is awful.
Ray Bradbury taught us that paper burns when exposed to oxygen at temperatures above 451°F. Dioxygen difluoride is so volatile that it makes almost any organic substance ignite and explode at any temperature hotter than 300°F below zero. It can literally make ice catch fire.
In an article about O2F2, Chemistry blogger Derek Lowe (of the excellent In The Pipeline
) used phrases like “violently hideous”, “deeply alarming”, and “chemicals that I never hope to encounter”.

Imagine: a colorless, odorless gas that will make any organic substance spontaneously combust and explode.  Is it necessary to point out, dear reader, that we are all made up of 100% certifiable, bonafide organic substances?  Shall I further elaborate on the horrors of such a compound? 

There is another article in there about ending the world via an 1.8terawatt hairdryer enclosed in a metal box.  I shit you not.

The stuff he comes up with is both fascinating and funny as hell all in one, and I highly recommend that you pop over and check it out.  Xkcd “what if?” FTW!  

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