potassium nitrate experimentsBy Esther Inglis-Arkell PO Edit6123L Burn a message into a piece of paper like a total badassRemember the burning bat signal in The Dark Knight Rises? Wasn't it cool? Now you can do a miniature version of it, only on a piece of paper instead of a bridge. Paper is far more portable, anyway. » 5/31/13 7:40am 5/31/13 7:40amWe Set Off Homemade Smoke Bombs — and Survive!