How Come Water Evaporates When On A Surface But Not In A Cup?

[IronWing]

Try putting the cup on the floor and report back.

 

[Muse]

part of it is also that air won't flow as quickly over the water in a cup since it's recessed within the cup (unless you fill it to the brim), further reducing evaporation rate.

Exactly, and the humidity level in the cup (below the rim) will be higher than that outside, further reducing the rate of evaporation.

 

[BarkingGhostar]

OK, normally I ignore posts by the OP but in this respect I got to say I am personally disappointed in his parents. If I could locate them, I would slap them simply for having given birth to the OP. 😛