At the New Yorker, Paige Williams visits forensic chemist Adam B. Hall to talk about the surprising things you can learn about bombs and their makers by looking at the effects they produce — from the type and color of the smoke, to the smell that lingers in the air, to what the “boom” sounds like. I’d take Hall’s speculation about the Boston Marathon bombings with a grain of salt (he’s making his judgements from low-grade video and isn’t part of the investigation), but the process he describes is absolutely fascinating.