That's an incredibly short amount of time - err, really?
250ms = 1/4s which I'd have thought was an eternity in the realm of atomic physics.
Perhaps this is more to do with thermal/fluid dynamics (which is presumably a bit more "physical world" speed) than the actual atomic interactions?
Still feels like quite a long time though. I mean, don't most car engine management systems operate on a 100ms timer for example?