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.