You can experienced this in pools! 12ft of water adds an extra 1/3 atmosphere of pressure, compressing the gas in your body by 25%. (That's why your ears pop!)

You can experienced this in pools! 12ft of water adds an extra 1/3 atmosphere of pressure, compressing the gas in your body by 25%. (That's why your ears pop!) By varying the amount of air in your lungs, you can choose which depth to be neutrally buoyant at. Weirdly fun!