chesch
Registered
You all couldn't be more wrong! Ever held a cup upside down underwater? Hair on the head causes leaks, wrinkles, bad seal on you forehead cause leaks! But something on the bottom of the cup / mask won't cause a leak! I have been diving with some kind of facial hair for 37 years! So unless you swim upside down all the time don't blame your hair!
So how does this cause a leak? The only way to leak is to have Air escape from the top of the mask!
Papa Bear,
Your logic is slightly flawed. The physics of an upside down cup holds true ... but that doesn't fully translate to a mask situation. Your mask isn't oriented in the same direction as the opening to the cup. If you were to always look vertically (at the surface) and have any openings to the mask pointed directly downward then this would hold true.
What happens if you were to alter your cup physics experiment? Put a full seal on the cup with the exception to two small slits oriented near the bottom of the cup, but not at the lowest points. Some water would be able to seep in this way. Maybe not a lot, but some water would be able to make it in there under the pressure...