how do guns/cannons/mortars work? How were they invented?
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Much of the ‘inventing’ was the refinement of gunpowder. It had been known since about 900AD in China and 1200 in Europe that you could put some fast burning substance in a tube, seal one end of the tube, and stuff would come out of the other end; and that you could hurt other people if you pointed the tube at them.
The first problem was to get the rate of burning just right. If it happened too slowly, the projectile would lazily slide out of the barrel and plop at the shooter’s feet. This was not only embarrassing, it was likely to get the shooter killed when his target was uninjured.
If the powder burned too fast, the gun would rupture, probably killing the shooter, or at least blinding him.
Powder manufacturers solved this issue by improving their production techniques, making sure that the grains of the ingredients were small and of uniform size. This was done with a sieve.
As manufacturers worked with smaller grain sizes, another problem arose: surface area. If the grains are really small, charcoal or sulfur – two of the ingredients – become explosive even without the other ingredients. ( BTW, this happens with almost any combustible substance if it has enough surface area. Flour mills have been known to explode when too much finely powdered flour gets suspended in the air. It sometimes does not even take a spark. Just the oxidation of newly exposed surfaces generates heat. )
The surface area problem was solved by using a solvent. That meant that there was no possibility of oxidation of the finely ground powder. Water was used initially. The ingredients were allowed to fall into a bowl of water as they came through the sieve. They were mixed together in water. When the water evaporated, the manufacturer had a dense, finely grained chunk of gunpowder.
However, there was a problem with water. If the gunpowder mixture stayed wet very long, the saltpeter would tend to crystalize and clump together. This produced powders that burned erratically. Trying to dry the powder quickly by warming it up was very dangerous, so gunpowder manufacturers began using alcohol instead of water.
Ethanol – AKA booze – was used first. It circumvented the surface area problem, and solved the crystallization problem. But it was flammable in high concentrations. So later, propanol – AKA rubbing alcohol – replaced it.
Now another problem began to appear. As guns became larger, the chunks of gunpowder became larger, and cracks became more common. This was not too much of a problem when water was used, for the slow drying time allowed the powder to adjust to shrinking stresses. But the faster drying alcohols tended to produce brittle chunks – which cracked.
Cracks, or fissures in gunpowder are deadly. They greatly increase the surface area, and now we are back to rupturing gun barrels.
I could go on, but this should be enough to illustrate the gradual step-by-step improvements – and the hazards.
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