From: Marc Crown (mcrown@gwhs.org)
Date: Wed Feb 12 2003 - 20:07:37 PST
Message-Id: <f05100329ba70c6a2c86b@[10.0.0.27]> Date: Wed, 12 Feb 2003 20:07:37 -0800 From: Marc Crown <mcrown@gwhs.org> Subject: Re: pinhole Re: Safe Explosions
We don't do explosions in my chem lab. We do stoichiometric reactions
with oxygen.
Here's a good one that I picked up thru the grapevine.
Materials
1 empty tennis ball can. Take a hot nail and make a hole on the side
near the bottom.
1 60ml syringe with rubber hose attached.
1 piezoelectric ignitor. Buy it from a catalogue or make it yourself
with a bbq lighter and some lamp cord. (don't forget to get a "butt
connector" from Radio Shack)
I can of butane
Procedure
Draw off 24ml of butane and "inject" thru the hole into the tennis ball can.
Light with the ignitor. It makes a very satisfying (and loud) pop and
shoots the lid across the room. *(altho we all know the lid should
really be pointing down)
Tease the kids a bit.
"if 24ml was that good, I wonder what twice as much will do??"
I wont bore you with the chemistry but there's no explosion and this
leads to a stoichimetry calculation.
It's fun and you can challenge the kids to calc the exact amount of
various combustible gasses that will react with oxygen in a 850-875ml
container.
It's almost as much fun as the "whoosh" bottle Eric showed me.
Marc
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