Heat and steam can also be a factor in a water breach. A phone that can be fully submerged into a pool of water may or may not stand up well to steam at its seams, particularly where those seams have different materials with different expansion rates due to heat, like glass and aluminum. Small gaps may open, even if invisible to the eye, and steam can seap in. It may not even be a problem immediately but get worse later when the steam cools and condensates.