We characterize observable sets for 1-dim Schrödinger equations in R: i∂ t u = (−∂ 2x + x 2m )u (with m ∈ N := {0, 1, . . . }). More precisely, we obtain what follows: First, when m = 0, E ⊂ R is an observable set at some time if and only if it is thick, namely, there is γ > 0 and L > 0 so thatSecond, when m = 1 (m ≥ 2 resp.), E is an observable set at some time (at any time resp. ) if and only if it is weakly thick, namelyFrom these, we see how potentials x 2m affect the observability (including the geometric structures of observable sets and the minimal observable time). Besides, we obtain several supplemental theorems for the above results, in particular, we find that a half line is an observable set at time T > 0 for the above equation with m = 1 if and only if T > π 2 .2010 Mathematics Subject Classification. 93B07, 35J10.