Sounds good to me, Dom.
Happy Diving!
Happy Diving!
What are the physics that cause
- Thread starter Otter
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> I believe ease of breathing is probably most related to the diver's perception of WORK of BREATHING (WOB, measured in joules, for which you expend calories), the physiologic equivalent to what most in this thread are describing in mechanical and physical terms.
> And these are all related. One expend's less energy when there is an "auto" assist, or boost, due to the thermodynamic (physical) laws applied, which indeed relate Boyle, gravity and buoyancy.
> Due to the height difference in the water column, gas expands according to Boyle's law.
> To satisfy your feeling (kinesthetic perception) of an adequate breath (an average respiratory Tidal Volume (TV) of 10cc/kg), your body does less muscular effort (diaphragmatic pull, thoracic intercostal, and scalenius muscle effort) when the inspired air column is expanding to meet this volume (aka, PV=nRT) due to the pressure gradient.
> Face up is harder (more WOB) because you add/expend energy for the same TV breath: More molecules in denser air moving in the same time frame (respiratory cycle) are inspired (increased resistance of breathing) against more extra-thoracic ambient pressure (chest expansion). Face down is easier. Vertical position of head down and feet up would "feel" easiest.
> This also proves correct according to the Laws of Thermodynamics in which the product PV is a known amount of energy; nRT - to be precise. At greater depth, and in the water column even millimeters matter, greater pressure exists. Ergo, PV is greater (more energy) and the WOB is greater in certain body positions.
> What a gas, uh?
> And these are all related. One expend's less energy when there is an "auto" assist, or boost, due to the thermodynamic (physical) laws applied, which indeed relate Boyle, gravity and buoyancy.
> Due to the height difference in the water column, gas expands according to Boyle's law.
> To satisfy your feeling (kinesthetic perception) of an adequate breath (an average respiratory Tidal Volume (TV) of 10cc/kg), your body does less muscular effort (diaphragmatic pull, thoracic intercostal, and scalenius muscle effort) when the inspired air column is expanding to meet this volume (aka, PV=nRT) due to the pressure gradient.
> Face up is harder (more WOB) because you add/expend energy for the same TV breath: More molecules in denser air moving in the same time frame (respiratory cycle) are inspired (increased resistance of breathing) against more extra-thoracic ambient pressure (chest expansion). Face down is easier. Vertical position of head down and feet up would "feel" easiest.
> This also proves correct according to the Laws of Thermodynamics in which the product PV is a known amount of energy; nRT - to be precise. At greater depth, and in the water column even millimeters matter, greater pressure exists. Ergo, PV is greater (more energy) and the WOB is greater in certain body positions.
> What a gas, uh?
OK, now my head hurts!
:wacko:
Dom
:wacko:
Dom
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