Join our expert "TechKnow" contributors Phil Torres, Kosta Grammatis, Rachelle Oldmixon and Lindsay Moran as they explore new technology and its impact on our lives. Kosta gets a look at how 3D printing can be used to make everything from home electronics to baked goods—even an artificial heart valve that expands as pediatric patients grow. Rachelle examines the impact of rising acidity in the oceans on oyster farms in California, and Lindsay investigates a hard plastic now sold to schools and students that might stop bullets from an armed attacker.