15/09/2017
When an adult or myself, "supine position (supine position)", the height of ears ~ mouth ~ nose is around 15 cm (roughly the "hot spring" of a hot bath facility). If you look up and float, water will not enter, but what about "looking sideways"? I think you will probably go drinking water . If you put your buttocks and hands, you can do it with no depth. But, if you are drinking and drinking, or falling down and losing consciousness, it is cowardly. I might have heard that "I drown even at a depth of 30 cm", but no no, I think that "15 cm is enough depth to drown". . Because it is shallow, I will not drown, I can not afford to be okay.