Falling into lava - a real world experiment

[Bruno]

There's been a sort of an argument on the internet about what happens when you fall into lava.

The version you see in movies is that it goes sort of "gloop" and you sink into it, possibly on fire but possibly not if the budget was short or they forgot. Sort of like a giant pot of boiling treacle. People always seem to thrash around so it doesn't seem to kill instantly in movies.

Generally the answer you get from geologists is that you go *splat* and break a bunch of bones, catch fire, and die very quickly. Not from stories about geologists falling into volcanos, but from the fact that even when molten, stone is rather more dense than bags of mostly water - you'll make a dent (depth depends on how fast you were going when you hit the lava) but like a cork on mercury, it'll bounce back and you'll still be basically on the surface, on an incredibly hot griddle (and without the benefit of a teflon no-stick coating, so you're probably cooked right-hard on it too).

For GURPS purposes, this says you should take falling damage (onto a yielding surface), before you even start burning merrily. Usually an academic problem, but RPGs are the home of exceptional people who can roll around all day on lava but not survive fall 100 feet off a cliff. For instance, a mage with Resist Fire active.

Science, however, fundamentally comes down to "Really? Lets try it!" Lacking a person to throw into the volcano, this video shows a large bag of household food waste being used as a proxy for a screaming victim. This is a pretty good "spherical cow" substitute - the food scraps are about the same density and water/carbon content as people.

This suggests that a more accurate sequence is that you go splash (more or less like landing in water), and you get coated in lava, much like in the movies. Then your water content flash-boils into steam that churns the lava, reducing the local density (helping you stay down until you are unrecognizably burnt up and broken into pieces) and sending geysers spraying around dramatically that could result in AOE splatter damage for innocent bystanders.

So now you know!

[Kuroshima]

Now we know!

I'll point my players to this next time one of them tells me you ought to be able to walk on lava if suitably protected

[johndallman]

I love these forums.

[DWChewie]

But keep in mind that a character who is somehow prevented from flash-boiling (said mage with resist fire, insane levels of Temperatur Tolerance, etc.) would not churn the lava, therefore not create an AOE.

Also in the video the waste seems to break the crust of the lava due to the fall.
If someone would simply walk onto lava, the result would look quite different.

EDIT: I also love this Forum :-)

[Ulzgoroth]

Originally Posted by DWChewie

But keep in mind that a character who is somehow prevented from flash-boiling (said mage with resist fire, insane levels of Temperatur Tolerance, etc.) would not churn the lava, therefore not create an AOE.

Also in the video the waste seems to break the crust of the lava due to the fall.
If someone would simply walk onto lava, the result would look quite different.

EDIT: I also love this Forum :-)

The video description notes that it is sometimes possible for humans to walk on lava, with the right equipment.


Also, yes, awesome.

[oneofmanynameless]

Thank you Bruno for bringing us our daily dose of awesome!

[Gollum]

Yes. Many thanks. As ever, your posts are very well documented.

[Bruno]

For more fun, same volcano, probably the same bunch of yahoos - this time a tank of propane.

Short version: they found a way to make a lake of lava more spectacular looking.

Cameraman: "What the *bleep* have you done?!"

Again, same guys, same volcano, water drum. Which takes the steam geysers from the food test to a new level.

Cameraman: "It seems to have invigorated the activity!"

[mr beer]

I want to know what kind of person, presented with easy access to bubbling lava, wouldn't throw stuff in there to see what happens.

[Tinman]

Bruno, thanks for the Awesome!