Newsgroups: rec.pyrotechnics
From: tip@ai.chem.ohiou.edu (Tom Perigrin)
Subject: Re: RE-Factor
Date: Thu, 21 Mar 1996 18:08:13 GMT

In article <4iqh1q$8u1@newsbf02.news.aol.com>, hh357@aol.com (HH357) wrote:
> 
> Not really a NM story, but maybe still instructive.
> About 60 years ago my dad worked in the oil fields.  He took a glass
> gallon  bottle, that had had hi-test gasoline in it. He emptied it out,
> filled it with water, swirled it around and dumped that out.  He then
> refilled the bottle half-way with more water, capped the bottle with his
> hand, and shook the bottle.
> KAPOW, the bottle detonated sending glass all over the work site.  Besides
> being a little dazzed, he only had a few small cuts.
>          You never know.

Well, it didn't detonate...  it experienced a low pressure explosion due to
vapor pressure.   I see this once or twice every quarter in my student lab,
although in a milder more controlled fashion.  (I tell them, I really tell
them, and they still mess up).

There is a device called a seperatory funnel.  It has a valve at the bottom
and a plug at the top.  You put two solutions into it - one solvent which
isn't soluble in water and one aqueous solution...  then you shake it.  The
things that are dissolved in the solutions partition according to their
solubility... salts tend to end up in the water, organic stuff tends to end
up in the solvent.   You allow the solvent and water to seperate, and then
you drain the two layers out through the valve, seperating them into two
containers...  (please don't nit pick those details, I know this is a
vastly simplified description).

When the solvents are first poured into the sep funnel, the air is just
air...  Then, when the thing is shaken, the water and solvent saturate the
trapped air with vapor.  The molecules in those vapors take up room, which
mean they have pressure...  and not just a little.  If the student doesn't
allow the pressure to escape then the plug is often shot out of the sep
funnel, often drenching the student or his/her neighbor with "stuff". This
is followed by the exciting "shall I stuff them under the emergency shower"
or "do I ask her to take off her blouse" decision time...

I suspect this is what happened to your dad.  The small amount of gasoline
left saturated the air in the half filled container (note it didn't do
anything when there was no air to become saturated), and the pressure blew
the bottom out of the bottle, which probably caused the whole thing to
shatter.

This is supported by the fact that the shards were not propelled with huge
force, else your dad would not have recieved only minor cuts.

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