making explosives from water

      • I got to talking about bombs & McGyver and stuff with the guys from work yesterday, and we started wondering if it was possible to make an explosive that uses water as an active ingredient. - Now, we are aware that there are substances that react violently when placed in contact with water; that’s not what we’re talking about. What we wanna know is if it is possible to mix a number of other ingredients and water, and have an explosive that can be ignited with a match (or primer/igniter) like any other regular explosive. The preparation can involve any number of intermediate steps, but the water’s gotta be necessary to the reaction and present in the final product- using it as an intermediate catalyst don’t count. The explosive hasta work in Earth’s atmosphere at regular temperature and pressure. It can be ridiculously expensive or incredibly impractical, as long as it goes boom. To appease the Greater Powers don’t post any actual instructions, just say if it can be done, and maybe mention the main ingredient other than water. - MC

[necessary to the reaction and present in the final product- using it as an intermediate catalyst don’t count. ]
water is a byproduct of many if not all conventional explosives.
a wet stick of dynamite will still go boom.
water might be used to ‘tone’ down an explosive, but not sure of this.
i would guess that some less refined explosives have some water in them.

you could always electricute a whole big bunch of water till you got a whole big bunch of oxyegn and hydrogen in a contained environment, and then just stick a fuse on top. light and run, baby. light and run.

manny, i tried to be as nonspecific as possible. If this is not kosher, feel free to yank.

The trouble with using “water” as an explosive is that it is already in it’s most highly oxidized form. The only element more electronegative than oxygen is fluorine, and flourine is thousands of times more rare than oxygen. And if you wanted you wanted to make a bomb with flourine as the oxidizer, there are thousands of better things to combine it with than water.

You can’t use water as an explosive unless you split it into hydrogen and oxygen via electrolysis and then recombine it, as mentioned previously. You’ll get the energy you spent splitting it back very quickly as the hydrogen burns.

Yes, you can dump sodium in water and it generates lots of hydrogen which expands and burns, but that’s not really the water exploding, it’s the sodium.

Your question is like asking, “Suppose I take ashes from the fireplace. Is there any way to make the ashes explode?”

Lemur–gonna have to disagree with you on this one. It * is * the water that’s doing the “exploding”–that’s where the hydrogen comes from (note that there is no Hydrogen in Na–which is what you throw in the water). Essentially, you’re doing the same thing as in electrolosys, just using Na. The Na donates electrons very quickly into anti-bonding orbitals of H2O, which breaks bonds and all sorts of fun stuff happens (namely, the formation of H2 and the rapid heating of said explosive gas). So it’s not the water per se exploding–it’s actually a quickly formed product of the reaction–but it’s not the Na in any way, shape or form.
Note that K workes even better at this–Na usually just causes fire on the water, K pretty much explodes.

Water can be used as a catalyst for an explosion when it comes into contact with the following materials.

In the order of least reactive through to most reactive:

Lithium (I’m not 100% sure about this)

[violating water as catalyst request in OP]
I’ve seen both sodium and potassium react with water. Sodium is somewhat ho-hum-ish, while potassium is somewhat impressive. I’ve never seen any other of the Group I metals react with water, so I can’t speak (write) to their explosiveness in water (although Gomez is correct about the reactivities (I’m fairly certain that lithium reacts slowly enough as to not be dangerous from an explosive standpoint).

A pyrophoric material that I have seen in action that makes potassium look like a match compared to a volcano, is triethylaluminum (TEA or TEAl) (most aluminum alkyls are pyrophoric, but this one reacts particularly violently with water. The only one I know of that is more reactive is trimethylaluminum (TMA or TMAl)). I work with the stuff in the lab, so when I had the opportunity to go on a tour of the plant that manufactures the stuff, I thought it would be a good idea to go. On the tour, they gave a demonstration of just how reactive it was with water. They had a 5 gallon metal bucket bolted to the ground, and filled with water, and a 100 foot long, quarter inch pipe leading from a pressurized tank of TEA (which is a liquid by the way) out to the bucket. Those of us watching the demonstration stood about 125 feet away from the bucket. When the guy in the foil suit (we were standing only 25 feet more away from the bucket… why didn’t we get one of those foil suits?) opened the valve on the tank, a pillar of orange fire and very black smoke shot up into the air about 80 feet. I can’t do justice to the description (it’s something you really have to see to appreciate). This thing was no slow burning, tall fire. It was like a rocket turned upside down. I don’t think I could impress upon the reader just how fast the fire was moving. The fire and smoke column lasted about 15 to 20 seconds. It was very loud. It shook your whole body at least twice as hard as the loudest concert you’ve ever been to. Probably the thing I remember the most vividly is the heat. The heat… WOW! Remember we were about 125 feet away, and all of the fire was going straight up, and the column of fire got no wider than twice the width of the bucket. The heat on us was similar to opening a 500 degree oven that sits on the floor, and bending down a little too quickly to get your food out. I’m sure most of us have experienced that. The heat on your face makes you jump back.

When the demonstration was over, everyone was in stunned silence. After a pause, I looked around at the others that were on the tour with me. Some people had moved back 10-15 feet, and this was the only time I’ve ever seen someone that can be described as having their jaw on the floor. We were informed that the demonstration we had just seen was the result of 1 pound of material. Without doing any calculation, and estimating, that’s about 1/7 of a gallon. That is, by far, the most impressive thing I’ve ever seen
[/violating water as catalyst request in OP]

BTW, when working with TEA before, I thought “Yeah, yeah… pyrophoric… don’t drop the container, open the container, or expose it to the atmosphere or water in any way… la te dah dah dah…” I was really casual (yet careful – I’m always careful in the lab) about my handling procedures. After the demonstration, I was VERY respectful of the handling procedures, as I regularly work with 2-3 pounds of the stuff at a time. Before the demonstration, I simply had no real appreciation of what “pyrophoric” could mean. Don’t even get me started on hazard warnings listed on MSDS’s (a MAJOR pet peeve of mine).

As a teenager I had the curiosity normal at that age and the desire to experiment… I knew about making H2 by attacking a metal with an acid so I decided to experiment… in a small bottle I put some iron filings and vinegar (the best ingredients I had).

I was looking to see what happened and nothing seemed to happen… I thought maybe the acid was not strong enough… how could I know if any H2 was being made?.. Light a match! Well I did, and the bottle exploded right in my face with such violence as you could not believe. I am so lucky nothing hit me in the eyes or I’d be blind today…

You mean the fact that the MSDS sheets barely tell you the difference between acetone as an irritant and something that’ll really rip your skin up?

potassium works well!!

Some silly kind in Junior high stole a hunk of it from the Science Lab. He was easy to catch later. He was the kid with the huge hole burned through his shorts and the second degree burns on his thighs.

Note to everyone: If you steal potassium, do not put it in your pocket and start sweating in PE. This is not a good thing!

Heh… Trying to get me started, even though I told you not to… I’ll try to keep it short, and not rant too much.

Yes, what you wrote is one gripe I have. The main problem with MSDS’s is that lawyers write them. Look up sodium chloride sometime. The MSDS I have at work tells me to wash my skin with copious amounts of soap and water for 15 minutes upon contact with the stuff. Companies are being forced by their lawyers to cover their asses when writing MSDS’s. As a result, you can’t trust your MSDS to tell you what the actual hazards are. If you can’t trust your MSDS, it looses some of its useless to the people who actually need it. I look at them anyway before using a new chemical, but I always ask around about the chemical, and take the MSDS information with a grain of salt (followed by washing with copious amounts of soap and water for 15 minutes :wink: ).

How about just some heavy water?

What about heavy water? It’ll sit there just lookin kinda deuterated at you.

I just wanted to get you started on the MSDS–they’re actually pretty amusing sometimes. :slight_smile: If you look up things that are put in everyday food products (beverages, packaged foods, and so on), it’ll tell you all sorts of dire consequences from accidental ingestion…sheesh. They’re also not laid out in the most user-friendly format, since they have exposure limits from about three different sources. It would be nice if they had a thing on top that clearly stated the dangers (in realistic terms) and then had the other two pages of mumbo-jumbo.

OK, here’s why I claimed that it was the sodium that was “really” causing the explosion rather than the water. Of course this is something of a semantics thing, but my feeling is that in order to get the pure sodium/potassium in the first place, you have to first create the sodium…you have to break apart the normal bonds between, say, sodium and chlorine to get the pure sodium. The sodium is now primed…it has a lot of potential energy stored in it. It could react with all kinds of things other than water, it’s just that water is the cheapest and simplest reagent. You could expose the sodium to air and it would react, albeit more slowly.

Sodium is simply a quick way to create hydrogen. The water is pretty inert…it’s the sodium that contains the “explosion”…just like you could make carbon dioxide explode, if you first split it into carbon and oxygen. But that’s not really a CO2 explosion.

Wait, I’ve figured out how to make a water explosion. Seal water in a tough metal can. Heat it until it’s about 300 degrees. Take an ax and chop open the metal can. Instant water explosion. Of course, the energy all comes from the fire you have going underneath it, but the water does explode.

“This thing was no slow burning, tall fire. It was like a rocket turned upside down.” --Steve-o

So where can i get a quart of this triethylaluminum and how much will it run me?