One thing I've been trying to explain to my players (one of them plays a character who's very into Philosophea and such), is how everything is built up of particles, being hot, dry, moist or and cold.
In A&A, the rules about motion and the lack of momentum suggests that parts of air are moved by the strength of a person throwing a rock, and the more strength he has, the more units of air he can move. Now, it also say that water too can have objects move through them. So air, being hot and moist can easily have objects move through them, and earth, being cold and dry, can not. Does this too go for other things than just the four elements?
Lets say a person is throwing a javelin at an enemy, wearing metal armor. He throws it into the air (hot and moist), then it hits the armor, being mostly cold and dry. Even if it can get through that (it would stop a most of the javelin), it begins piercing flesh (moist and hot?) and bone (cold and dry?).
So is this correct, that the object being thrown, will try do move units of whatever it is in front of it, and the more elements of air it has in it, the better it moves? This is also the reason metal armor is so effective, being made mostly of hot and dry particles, in other words: earth, which cannot precipitate movement?
Sort of. It is mainly to do with how much resistance there is in a medium; objects move faster through media with lower resistance. Fire has the lowest resistance of all, then air, water, and lastly earth. It is more to do with the secondary qualities (density, resistance, flexibility) than primary qualities (hot, dry, moist, cold). Hot things (rich in fire and air) are less dense than cold things (rich in water and earth). So broadly speaking your explanation is sound; flesh is hotter than bone, which is hotter than metal.
I found this to be extremely informative and really cool explanation of physics in ME. Thanks to both for this thread This is what makes Ars so interesting to me.
I meant to add: hot things are less dense because the basic nature imparted by heat is to expand and separate, thus the atoms are further apart. Cold things coagulate and stick together, making them denser.
So, everything being equal would a fire sword would have more difficulty in breaking through a metal armour (less damage) that an air sword? The metal sword is less dense, right? None of the above, vice versa or something different altogether?
I'm not sure I'm understanding you. A fire sword (if you mean a sword made of fire) would not be able to break through metal at all, not would an air sword. Neither have the rigidity or solidity required.
Yes, I was talking from a "high fantasy" sword concept: the archetypical sword made of Fire but that acts like a solid sword. Would the fact that it is fire (and so, tends to expand) limit its penetrative power over one made of a denser element?
But what happens if two items of the same material and density, but different size hit each other. Is it the density of the material in motion that decides what it can break through? For instance, an arrow, with a small, sharp point, would have to break through less of the material it hits, therefore losing less of it's strength imparted by the initial mover.. is that right? And to go back to the really early days. What about one rock hitting another rock with the same density but different weights? How would Aristotles explain why the smaller rock breaks?
My head's spinning already I should quit thinking about this now, and really concentrate on taking my driver's license tomorrow.
Dunno if the theory of the period would be able to define it, but the mundanes dealing with the Art of War were perfectly aware that pointy things had more penetrative power than blunt ones. However, blunt items could break stuff where the pointy things were unable to enter. This is why a chain mail is useless unless it is backed by a gambesson: one protects against crushing damage and the other against penetrative damage.
Still, a larger arrow (read, ballista) will cause more damage than a smaller arrow, so I cannot see why smaller would mean more damage in ME
Here we're talking about the strength of the initial mover again. The arrow from the ballista is large, sharp (but not as sharp as a small arrow) and is flung by a mechanism able to send it with great strength (which, as A&A says, is the only important thing). Since the arrow is shot out with such strength, the arrow can move more units of air (and the units are larger for larger objects), but when it hits, the point of impact is small (a sharp point) so it takes less of the strength of the initial mover to punch through the target. Every object has a resistance based on how much air, fire, water or earth it is composed of, so to speak.
Well, that's my theory at least
I've just read the article in Sub Rosa about explosives. There it reads that small firearms will never work because the smaller bullet will only fly further, but not strike harder. It seems I'm still not understanding how this works. So let me try to explain it to my self again, and maybe someone can point out where I'm mistaken
Right, an object being thrown by a strong man will get more strength from the thrower to push through the resistance of the air. When this object hits something, it will try to push through the resistance of whatever it hits, thereby doing damage to it. The resistance of the thing the object hits depend on what it is made from. Since the object will try to move as far as it can through whatever it hits, be it air, or something else, it will do damage based on how much power it is thrown with, although it won't fly faster toward the target. If it hits something made up of cold and dry particles, it will most likely stop there and then, if the object being thrown isn't even colder and dryer.
So what about Crossbows? Even the lightest crossbows used in medieval times were quite lethal. And the bolt shot from these crossbows were quite small. I also heard that some crossbows shot small stones. Anyway, how would crossbows and bows fit in with the physics of Mythic Europe, where the lethal part is only the small point of the arrow or bolt. The rest of the projectile is basically used to stabilize it in flight (and of course to add damage due to the added weight). If an object is thrown violently through the air and onto a target, isn't really any difference what kind of initial mover it uses (be it bowstring or black powder?) A&A says that only "the strength of the initial mover is important".
Any thoughts? (Or should I get out more and think about other stuff too.. lol)
I should quit thinking about this now, and really concentrate on taking my driver's license tomorrow. 
