Here's how you make glass bulletproof — on only one side

We're used to thinking of things as either/or -– especially when those things are panes of bulletproof glass and we're sitting behind them. How do people make glass that can stop a bullet one way, but let bullets fly through them another way? We'll take a look at the physics of bulletproof glass. » 2/08/13 7:20am 2/08/13 7:20am