Kevlar and ceramic body armor can potentially stop a bullet and prevent the death of a soldier, but tends to be bulky and restricts movement. Certain types of armaments can also pierce Kevlar. Defense contractors have been searching for a way to make armor lighter and provide additional protection, and a new method involving liquids could do just that.
BAE systems has researched and developed a new liquid-gel based armor. BAE use a shear-thickening fluid that flows just like traditional liquids, but hardens on sudden impacts or when stress is applied. When hit with a bullet, the gel hardens to the point where it stops all movement.
While Kevlar is known to be five times stronger than steel, and can stop a bullet effectively, it can leave severe bruising and minor injuries. All of the energy of the bullet is focused into one spot, which Kevlar does very little to prevent. The gel-based armor, meanwhile, spreads that energy out over the entire surface.
BAE say that they can put ten layers of the gel between two layers of Kevlar in order to create a lightweight armor that can withstand a bullet from a 10mm pistol. The amount of protection can also be increased to withstand larger bullets, like from an AK-47. Even that would be lighter than traditional body armor, allowing greater freedom of movement, as well as being cooler.