Gifs Explained: Exploding Coffee

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A few months ago, Buzzfeed posted a list called “21 Reasons Why You Should Have Paid Attention In Science Class,” composed of a bunch of cool, weird sciencey gifs. My initial reaction was, “Okay, pretty neat, but what am I actually seeing here?” Plenty of comments on the post echoed that thought, but Buzzfeed still hasn’t answered the cries of the writhing, curious masses.

I figure it's about time to take matters into my own hands and start explaining these things, starting with the ones from the original list that I can figure out or trace back to their source. Best case scenario, that gives us 21 cool gifs. Obviously, that’s not all the cool science gifs out there, so if you find any sciencey gifs or images that make you say, “Huh? What the heck is going on there?” send them my way!

Anyway, here’s our first gif, featuring what appears to be a cup of coffee exploding into a miniature Leaning Tower of Pisa.


So, what the heck is going on here?

Well, to start, that’s not coffee in there. It’s actually p-nitroaniline and sulfuric acid, which I cannot recommend drinking for a morning pick-me-up. When brought together and heated, the two go through what chemistry textbooks dryly refer to as a “vigorous reaction,” where they decompose and form a solid black-brown foam.

NASA studied the reaction in the 1970s because the foams which are formed have a low density and are flame-retardant, and had potential as a fire-control measure in the tight confines of spaceships. Here’s what they had to say about the reaction:

“The first, or pre-expansion, stage is the interval up to about 230°C. Water is the major gaseous constituent, with some nitroaniline subliming at higher mole ratios; sulfur dioxide is absent. Dehydration and sulfonation are the main chemical processes; some deamination also takes place.

“The second, or aphrogenic (intumescent), stage begins at about 230°C for 4- nitroaniline…and is over within a 50° interval when the heating rate is 6°/min. Sulfur dioxide and water are major gaseous products. [This is when the foamy tentacle bursts forth - Matt].

“The third stage, in air, represents oxidative decomposition of the residue (the primary product of the exothermal reaction) and dissociation of variable amounts of ammonium salts present in the residue.”

In layman’s terms, as the nitroaniline and acid climb in temperature, they experience some different chemical processes—losing water and amines and gaining sulfur compounds—and then explode into foam, which then breaks down.

You can see the buildup to the explosion in this video, which the gif was taken from.

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September 10, 2013 - 12:00pm
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