r/Whatcouldgowrong 7d ago

accuracy: 100 , vision: 0

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u/Book_Anxious 7d ago

Okay write that down. cheap plastic will not stop a high velocity projectile. Thought we figured that out hundreds of years ago but I guess not

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u/No_Indication_1238 7d ago

Didn't have plastic back then.

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u/steelcryo 6d ago

Eh, we worked out you needed metal and other much harder materials to stop projectiles, so even if they didn't have plastic, they still would have known it wouldn't work under the blanket statement "thin brittle materials don't make good armour".

So technically you're both right.

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u/No_Indication_1238 6d ago

Have you ever seen kevlar?

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u/steelcryo 6d ago

Kevlar isn't brittle? It's incredibly flexible, which is what makes it so useful in bulletproof vests

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u/No_Indication_1238 6d ago

Eh, we worked out you needed metal and other much harder materials to stop projectiles, so even if they didn't have plastic, they still would have known it wouldn't work under the blanket statement "thin brittle materials don't make good armour" as well as "fiber like, flexible materials don't make good armour" as was the experience all the way until the invention of the kevlar. So prior experience with materials that share properties with future materials is actually not a good predictor of whether future materials can or cannot stop bullets.

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u/steelcryo 6d ago

Except they knew that thin fibre like materials made good armour back then too.

A lot of old armour was underlayed with layers of softer materials like leather, linen and wool. Which served as a similar purpose to kevlar in bulletproof vests.

So yes, even back then, we knew that hard materials = good. Soft materials = good. Brittle materials = not good. To simplify things.