Physics Rant: The Truth to Buoyancy in Diving

[ScubaSteve]

i dgaf bout bouyancy, i spent my first few dives literally upside down, fins in the air... or water rather. you get the point

:headscratch:

 

[GrandpaScuba]

Okay, rant over. I hope I educated at least one of you. Begin the ridicule!

I, too, am an engineer and I don't have any problem with the diving terms. You see, diving is a different discipline than mechanical engineering. It is not uncommon for different disciplines to use the same words to mean different things. Even when the concepts are similar.

Both painters and musicians refer to "color", but strictly speaking, the musical term means something completely different than what the painter uses the term for. Staying on the musical theme, in music "tone" refers to specific sound of a specific frequency. In audio engineering, tone refers to whether a circuit favors higher or lower frequencies.

Each discipline has it's own Jargon. The jargon is created by the members of the discipline to allow them to speak to each other in an efficient manner. Just because a word has some specific definition in one jargon, doesn't mean that it has to have the same meaning in another jargon.

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A foolish consistency is the hobgoblin of little minds -Ralph Waldo Emerson

 

[J.R.]

Both painters and musicians refer to "color", but strictly speaking, the musical term means something completely different than what the painter uses the term for. Staying on the musical theme, in music "tone" refers to specific sound of a specific frequency. In audio engineering, tone refers to whether a circuit favors higher or lower frequencies.

Ah, yes... that "context" thingie... Excellent point. Reminds me of the definition of "black"... Is it the presence or absence of color? ... and the answer depends on whether you're talking optics or pigments...

 

[gNats]

Okay, rant over. I hope I educated at least one of you. Begin the ridicule!Tom

AAAAAAUUUUUGGGGGGHHHHHHHH!!!!!

My brain, my brain.... oooooo shiny thing, lookie!

Thanks Tom for the um, education. I must say, I much prefer saying I am floating, hovering or sinking when describing my own boyancy position in the water.

 

[Blackwood]

AAAAAAUUUUUGGGGGGHHHHHHHH!!!!!

My brain, my brain.... oooooo shiny thing, lookie!

Thanks Tom for the um, education. I must say, I much prefer saying I am floating, hovering or sinking when describing my own boyancy position in the water.

Problem being that a similar discussion regarding semantics follow usage of the term "floating."

 

[LarryHinDC]

Tom,

With your proposed alternatives, you risk mixing up mass and weight. :crazyeye: My mass doesn't change (except for use of air) during a dive, so to say that at times I am heavy (sinking) and sometimes I am not seems confusing in itself. I think earlier suggestions about using the term 'net buoyancy' have merit, and to keep your sanity, just assume the word 'net' is implied.

 

[Gombessa]

Tom,

With your proposed alternatives, you risk mixing up mass and weight. :crazyeye: My mass doesn't change (except for use of air) during a dive, so to say that at times I am heavy (sinking) and sometimes I am not seems confusing in itself. I think earlier suggestions about using the term 'net buoyancy' have merit, and to keep your sanity, just assume the word 'net' is implied.

Not to mention that "heavy" and "light" are by nature completely subjective terms. Is a feather heavy? Compared to what? Can a heavy feather float? It's rather surprising that an engineer would propose such terminology to replace what is already descriptive and unambiguous.

 

[Guba]

Ditto what CatfishBob said.

And I'm a physics teacher....

With a degree in English.

 

[siikik]

...There are pretty much two forces at play while we are diving that contribute to what we refer to as 'buoyancy': Gravity, and Buoyancy. For simplicity, we will define Gravity as the 'downward' magnetic pull of the Earth on any object with Mass (ie, how much something weighs). Buoyancy we will define as the 'upward' force imparted by water to a submerged object....

So... my BCD, which really has nothing to do with buoyancy, is really a gravity compensator device! I like it!



Ken

 

[AbyssalPlains]

Thank you for posting this educational rant. I can relate to you very well. Sometimes I wonder how we even manage to not go crazy in a sport in which volume is measured in pounds, as in "How much air do you have left?" -"700 pounds"

or
we are being taught that in an OOA ascent, "air expands in the hoses"

or
enriched air mixtures are described as "hot"

or
I could go on and on and on.

Frustrating to see the carelessness and lack of understanding of physical and physiological concepts in an activity that depends so much on proper grasp of concepts.