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Comment by mod | Hacker News Reader

If I were making those caskets, I'd just put a one-way release valve on it.

I think it's interesting that reactions can produce so much pressure, given that all the components "fit" into the space prior.

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All of the components of diet coke and mentos fit into the bottle prior :)

Consider how a rocket engine works.

I don't actually know, but most engines are using gas from outside of the fuel source. I suppose perhaps they use a stored gas, given that they'd need it in space, or perhaps couldn't "grab" enough for the huge amount of fuel they're using.

That said I'm aware of plenty of situations where similar things occur, I still find it very interesting.

Rockets don't use anything from outside. Otherwise they wouldn't work in space too well, since it's a vacuum.

Perhaps you didn't read my full comment.

Maybe I didn't understand it, but I read the whole thing. "I suppose perhaps" is pretty far from a statement of certainty, if that's the part you think I missed.

Rockets contains both oxidizer and fuel in liquid or solid forms, sometimes separated and sometimes even in one substance (monopropellants). Combustion products are gaseous, and gases tend to take more space than solids or liquids.

Of course, if the combustion products didn't take up more space, the rocket would be remarkable in its ineffectiveness...

The heat of combustion will also cause more space to be taken up.

Come on, it's not rocket science.

The key difference between a rocket engine and other types of engine is that rocket engines only use chemicals that are stored onboard. If it needs gas from outside then by definition it's not really a rocket.

Pretty much any time you turn a liquid into a gas, it takes up a _lot_ more space.

Is there a pressure point at which the transformation cannot occur? (Obviously far beyond the realm of what a casket is going to contain)

Yes, for any substance and temperature, there are ranges of pressures where it's gas, liquid, or solid. Look up "phase transition diagram" to get a better idea. But it's basically going to be different for every substance and every mixture of substances, so it's probably hard to predict at what pressure the gases coming off a corpse are going to liquefy.

But why deprecate the blow-up feature?

Let's offer the valve as an "option" for the less venturous types! :-)

This is the same case with bombs.

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