Nibbling around the definitions

We’re still nibbling around that pesky definition of “explosion.”  I actually thought I had something that would work as a qualifier until the daughter asked a smart question.

Qualifier: “release of energy generates a shock wave.”  Question: “Can you have a shock wave in a vacuum?” (implied: explosions in space are possible.)  Answer: dunno – more research.

Still, I think we may be closing on a definition that is heavier than a hand wave. (rapid release of energy, violent release of energy, WHAT SO-CALLED SCIENTIEST wrote these?  sigh).

On a digression, we discovered a couple of critical terms for chemical explosions.  (A subset, which means most of the definitions that actuall work for them don’t work for other subsets such as mechanical explosions.) Anyway, we have “fast” and “slow” explosions – with specific terms and a clear point of demarcation.  Fast is a detonation. Slow is a deflagration.  The point of demarcation is based on speed of the burn.  Specifically, it’s the speed of sound.  Again we’re back to the shock wave question, but at least I’ve got a glimmer of an idea.  Oh, it also appears that these chemists are only considering chemical combustion explosions – a further subset.  Because I can combine two non-oxygenated substances in a vacuum and get an expansion that explodes.   Since it’s due to a chemical reaction it’s a chemical explosion even though it’s otherwise a mechanical explosion.  Yep, again I am stumbling against definitions that aren’t definitions but merely working phrases.

Touches of brilliance from the daughter (besides the question above).  As in, she decided she needed a notebook.  Sadly we’re not able to get or make a “proper” notebook – one which is hard-bound for which adding and deleting pages is difficult without being noticed.  But she’s decided at this level it’s not needed – a basic binder will do.  As we progress we’ll do the formal binder thing.

And if we do, I’ll probably do it right. See, way back when I learned how to bind. Yes, properly it’s done with sheets that are folded.  But you can still do it with flat sheets – it’s just a wee bit less durable.  100 sheets of small-grid (1/4 in or 5mm work well for the most part).  hmmm, seeing that, I want to make a recommendation.

I cannot recommend incompetech.com’s graphpaper resource enough.  Free graph paper – decide what you want and print it.  Oh, not just square grid graphs. There are dots, crossgrids, axanometric grids, plus really different things such as hexes, logarithmics, polar plots, ledger, perspective… enough.  Go look.

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2 thoughts on “Nibbling around the definitions

  1. The definitions suck because “everyone” “knows” what an explosion is.

    The real question is…. why do YOU seem to care so much? Who cares? I’ll measure what I care about when I care about them. Energy flux is a pretty good measurement for a space based weapon. Shock waves are generally what matter for blowing things apart in atmosphere. (Which is why ANFO is awesome for dropping rocks in a quarry and pretty crappy for taking down buildings…..regardless of what the D.H.S. tries to sell you)

    If you just want to play with things that go boom, I’d start with an ANFO bomb. ANFO is REALLY REALLY safe, right up until you light it off. In fact, dropping a match on the AN part will NOT set it off, until you soak it with the FO part. Just make sure its a small bomb or D.H.S. will knock on your door. Black Powder, TNT, all the other stuff I can think of that I can make without causing all kinds of flags to go off, they aren’t so safe.

  2. Puzzling on the definition is part of the exploration process – the curiosity factor. I am delighted you intuitively know what needs measured. I don’t. Part of figuring out what is needed – of deciding what it is I care about – is this process.

    I will be doing ANFO for a variety of reasons. I will, however, be doing other explosives. Why?

    I’m teaching. Incidentally I’m learning, but I’m teaching. And the single most important thing I’m teaching is the it is not only good but right to scratch the curiosity bump – with a strong secondary being make sure you do so as safely as possible.

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