What is a bulletproof vest made out of? --- Abdul, Hyderabad, India
Marshall Brain Answers:
For civilians, by far the most popular option for a bulletproof vest (aka body armor) is layered Kevlar. This material makes a thin, light vest that provides good protection against smaller handguns. See How Body Armor Works for details.
In war zones where high-powered military rifles and grenades are used, more protection is needed. Metal, ceramic or thick plastic plates slip into pockets on the vest. This video shows how the combination of soft body armor and rigid plates works:
A typical plate being tested:
There has been extensive work in what is known as liquid body armor - armor that stiffens when a bullet hits it. See How Liquid Body Armor Works and this video for details: