Re: [Phys-L] exploring explosions

[Bill Norwood <bnorwood111@gmail.com>]

David,
- Working with young people you have an excellent opportunity to provide
them research info which will aid them in a vital health and safety
decision.
- They will be deciding whether to use e-cigarettes.
- What a great opportunity to get them involved in the physics involved in
e-cigerette explosions, when they are already intrigued by dynamite
explosions
- Plenty of articles come up if one will do a search on e-cigarette
explosions.
- Students could build apparatus within which they would force 2 or 3 types
of e-cigarette explosions to occur. And they could measure damage done as
well as estimate the forces involved, and perhaps even determine and
evaluate some of the gases and particulates in the air.
- I would be interested if you find that you can use this idea.
Bill Norwood
Manager Elementary Labs
Physics Dept
U of MD at College Park

On Dec 6, 2016 3:54 PM, "John Denker" <jsd@av8n.com> wrote:

> On 12/05/2016 02:01 PM, David Strasburger asked:
> > What are some simple interesting ways to measure an explosion?
>
> NOTE:  These are offered in the spirit of hypotheses for
> the experts to consider.  I am not an expert, and would
> not presume to offer suggestions, especially where it comes
> to the safety issues.
>
>
> 1) Hypothetically, one might measure the velocity of detonation.
>  In physics context this would be called /speed/ (not velocity),
>  but it would be bad manners to argue the point.  Organic chemistry
>  is different from organic vegetables.  Context matters.
>
>  Hypothetically, the blasting crew might be interested in this
>  for their own reasons.  The speed is enormous, but still
>  measurable.  One way is the D'Autriche method.  It is not an
>  absolute measurement, but measures one explosive relative to
>  another.  It's not obvious a_priori that this should work,
>  but it does.
>    https://books.google.com/books?id=xyRG0J6VCPsC&dq=
> dautriche%20method&pg=PA72#v=onepage
>
> 2) Here is a way of illustrating the third law of motion in a
>  super-authentic real-world situation:  Tamping.  There are a
>  lot of ways of doing this.  Here is a simplified notion:
>
>                 Safety mat: =========================
>                 Spacer:     /   /   /       /   /   /
>                 Spacer:     /   /   /   X   /   /   /
>                 Plate:      ------------------------
>                 Spacer:     /   /   /       /   /   /
>                 Ground:     #########################
>
>  Make the spacer flimsy, like a shipping pallet, mostly empty
>  space.  Put a small amount of explosive on top of the witness
>  plate, at position X, with no tamping.
>
>  Repeat the experiment with tamping, i.e. with a couple of sand
>  bags on top of the explosive.
>
>  This makes the point that the effects of an explosion don't
>  simply happen "because there was an explosion".  They happen
>  in accordance with the laws of physics.
>
>     https://www.google.com/search?q=tamping+%22witness+plate%22
>
> 3) Hypothetically, one could acquire the seismometer data.
>  Print it out and post it on a wall somewhere, with all
>  channels side-by-side.  This should tell you something
>  about the subsurface geology.
>
> -----------
>
> This should give you some ideas.  Of course it all depends on
> whether the blasting crew wants to play along.
>
> I have some marvelous additional hypotheses, but the margin of
> this email is too small to contain them.
>
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