How did knights urinate with their armour on?
Knights typically wore a type of armor that included a protective codpiece, which allowed for some degree of access. When they needed to urinate, they would often have to unfasten their armor, particularly the lower parts, or lift their chainmail or plates, which could be cumbersome. In some cases, they might have used a chamber pot or simply found a secluded spot to relieve themselves. However, this process was not convenient and often required assistance, especially if the knight was in full armor.
When did armed soldiers begin to use metal plates to their mail armor?
In the 13th century soldiers began to strengthen their protective mail. They used metal plates to protect the places on their bodies that were exposed despite the mail chains.
What is a bulletproof jacket made of?
A bullet proof jacket is made from several thin layers of a material known as kevlar ( Kevlar is a registered trade mark). Kevlar is a para-aramid synthetic fibre. Some vests also allow for metal plates to be inserted. While kevlar is light-weight, inserted metal plates make the vest heavier. Though if the vest stops a bullet, I doubt the wearer would mind how heavy the vest was.