The spell "detect magic" lasts for 1 minute/level. It says:
You detect magic items and spells, or identify a magic item. On the round you cast it, you sense if any are in range. On round 2, you know how many there are. On round 3, you know exactly which things are magic. If cast on a magic item, you learn its powers.
But It does not make sense: for my level 1 cleric the duration is one minute (1/1 right?). 3 rounds are 18 seconds. I don't get this. Does it mean that I need to take 4 rounds (72 seconds) just to make the first step of the spell? Or am I doing it wrong?