Physics Rant: The Truth to Buoyancy in Diving

[clint@uniquescuba.com]

Archimedes Principal or Archimedes Law?

 

[bigken462]

There is a pill for everything. I'll get back to a when my mind clears of the jibberish and let ya know which is best for ya. For now, my suggestion would be to dive, dive real deep - perhaps on air

Dive safe though. Lol

Kenny

 

[IceBergSlim]

Wow.

What an amazingly condescending rant.

 

[TSandM]

Actually, I empathize. I HATE writing "negative buoyancy", because it's just wrong. But if you're trying to explain stuff to a new diver, there really aren't good terms, because you want to highlight that the forces are acting in OPPOSITE directions and summing to a single result. This is particularly bad when you are trying to discuss balancing gear for horizontal trim. I suppose I could just say "upward force" and "downward force", but since buoyancy is universally used in the original instruction, it just seems easier to use it subsequently, no matter how basically inappropriate the use may be.

As any aging woman can attest, Gravity is at work on us at all times

Oh, man, THIS one struck home . . .

 

[J.R.]

Actually, I empathize. I HATE writing "negative buoyancy", because it's just wrong.

Somebody better inform NASA... seems they don't see things quite the same way (If one can have 'neutral bouyancy'... as in "Neutral Bouyancy Labratory" I assume that 'positive bouyancy' and 'negative bouyancy' would be the bookends).

In any case... the *interesting* philosophic point to me is the question regarding the point at which 'bouyancy" occurs? Does bouyancy necessarily occur at the interface between mediums (ie, air and sea)... or can it occur at some density point in the air column... or at some density point in the water column???

Hummm...

 

[Gombessa]

Archimedes Principal or Archimedes Law?

Let's not call it a law until our diligent fundamentalists can confirm that it doesn't contradict the bible. Archimedes' Theory would be acceptable.

 

[Soggy_Diver]

OK, I get the point of the original post.

But language is basically metaphorical, as well as literal. And words mean different things in different communities. So if divers can communicate effectively by calling a phenomenon "negative buoyancy," then that may be wrong usage for physics, but it is right usage for diving.

Ironically, the same point applies to the original post, which reads...

For simplicity, we will define Gravity as the 'downward' magnetic pull of the Earth on any object with Mass (ie, how much something weighs).

...which is wrong as physics, but an understandable metaphor.

 

[J.R.]

Archimedes' Suggestion...

 

[Thalassamania]

I sympathize with those who require precision in language, especially technical language. However, as a Taxonomist (who has never been confused by an Ornithorhynchus anatinus) and one who also happens to be a submersible pilot, I have to say that the use of "negative" and "positive" as a way to describe the buoyancy state of a vehicle (or person) immersed in a fluid is a, "term of art" of long standing. Remember ... subs have been blowing negative and blowing positive for many more years than there have been scuba divers.

 

[Sas]

Can I refer to my lead weights as antibuoyancy pods?

To be honest, I think the OP's terminology is more confusing, "heavy" for something that sinks? I like the second lot: "floats", "hovers" or "sinks", but still don't care if people use positive, neutral or negatively buoyancy though. I don't think that language needs to be technically correct most of the time, language should be used in a way that the majority of people understand it, even if it is not "technically correct". Like when I teaching my mum how her computer works, I use language that would make most IT people cringe, but she understands it a lot better than the technically correct terminology