Water Preasure Please answer.... hi, I'm from the uk, I am a complete novice (no physics PHDs) Please dont Flame me..., I just registered on the site to get an answer to a question that my mates are arguing about. I'm sorry if its trivial or posted in the wrong forum. My question is, If I filled a glass of water and inverted it and held it above the surface of the tank of water, the water stays in the glass. Now, if you were to imagine a miniature submarine that started at the top of the glass and descended down what would the pressure gauge read as it traveled down the glass? And then the pressure at the bottom of the glass level with the surface water of the tank? I would then expect the reading to increase in pressure as it descends into the tank as normal. If anyone can settle this argument much appreciated.... thanks adam a physics newbie.