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Thermite vs ice = explosion

Travis

Misanthrope of the Mountains
Travis
Joined
Mar 31, 2007
Messages
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On the latest episode of Mythbusters they confirm that igniting thermite in a bucket on top of a block of ice results in a strange, concussive explosion. However the reason behind this is left unresolved by the episode.

Does anyone have any guesses as to what is causing this phenomena?
 
Claim that WTC core columns were actually made of ice in 3...2...1...
 
Thermite produces huge amounts of energy, so what I suspect is happening is that the molten iron burns a smallish hole through the surface of the ice, it flows into this hole and vaporizes a larger cavity underneath. The ice wouldn't all vaporize at that time (if nothing else ice chunks are easily visible after the explosion.) Enough should remain on the top and sides to make a passable chamber for a small rocket to form (the giant plume of death spraying out start at 0:06) due to steam production and further thermite reacting. The explosion would be due to steam production that is too great to be vented through the hole through the top of the ice, so it exploded.

I always knew there was a reason rockets aren't made from plastic buckets of ice. :D
 
I think it might be small amounts of hydrogen formed by aluminium reducing water. When the concentraction is high enough it goes boom.
 
I assume it's what Jamespatterson said. If you produce lots of gas in an enclosed space, you get an explosion once the pressure is too great to contain.

Why were they looking at this anyway? The interaction between thermite and ice hardly seems like a common topic of discussion that they'd be interested in investigating.
 
Cuddles said:
{snip} Why were they looking at this anyway? The interaction between thermite and ice hardly seems like a common topic of discussion that they'd be interested in investigating.
Click to expand...
If you watch "The Thing from Another World" (1951) you will see that they attempt to release the UFO from ice using thermite. The explosion is too violent, and destroys the ship. So, the connection is obviously related to UFO investigations. It confirms that an alien space ship encased in ice could be destroyed by thermite.
 
soylent said:
I think it might be small amounts of hydrogen formed by aluminium reducing water. When the concentraction is high enough it goes boom.
Click to expand...

If anything is reducing water, it'd be the iron. The aluminium is already fully oxidised, by virtue of having taken part in the thermite reaction in the first place, and can't reduce anything else.
 
Wow, that was one big boom! It must almost certainly be a chemical reaction, so I also guess at some reduction of water, possibly combined with the effect of all the thermite being ignited in a much shorter time than the normal burn (oxygen released?).

If the origin of the idea is somebody attempting to burn a nice hole in ice with thermite, then that somebody was sure in for a nasty surprise! :eek:

Hans
 
A couple of observations:

Volkswagen magnesium engine casing in a fire hardly burn- until you throw some ice onto them. Then they become magnesium flares.

A sealed can of warm beer thrown into a camp fire with get a hole in it, and fizzzzz. A sealed can of cold beer will explode.

So, heat and water do strange things to metals in the aluminum/magnesium/beer family. ;)
 
Cuddles said:
Why were they looking at this anyway? The interaction between thermite and ice hardly seems like a common topic of discussion that they'd be interested in investigating.
Click to expand...

It was based off an internet video they found. They've been doing a lot of things like that since so many are faked.
 
I worked briefly in an aluminum plant, and mention was constantly made of the dangers of steam explosions- when water gets into something as hot as a large pool of molten cryolite (or in the case of thermite, molten iron) it simply explodes into steam.

If the iron reacted with water to give hydrogen, which then burned, that wouldn't be any more exothermic overall than the molten iron burning, which it doesn't really do.

Of course, I've done the thermite reaction dozens of times, and often with the reaction vessel (half a pop can) stuck in a snowbank. Never a problem.
 
For all the apparent violence of the explosion it doesn't appear to have much effect on the foreground wreckage. Loose wires and debris don't appear to move, the camera barely shifts and the car vibrates a little. Very showy but not a lot of oomph.
 
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