Silicon is everywhere. It can be found in the rocks under our feet, in the windows of our homes, and in the brain of every smartphone. Without silicon to make computer chips, there would be no Silicon Valley in California. Silicon is second only to oxygen as the most common element in the earth's crust. Silicon isn't always hard, either. It's found in objects as bendable as a spatula or as stretchy as a bouncing putty. Tubes containing silicon can...