If you strike a safety match on the approved, official strip on the side of the box, the match burns just fine. So why can't you generate a spark when you strike a safety match on, say, concrete? Cast iron? Brick?
-- Milo, San Diego
It takes four volatile, smelly chemicals to set the tip of a match afire. In the non-safety variety, all four are mashed together in the match head. In the safety kind, three are in the match and the fourth is in the striking strip. Like a pyromaniacal alchemist, you're incorporating the magical fourth ingredient when you rub the match against the strip.