Physics Rant: The Truth to Buoyancy in Diving

[AbyssalPlains]

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

Forgive me for being picky, but since this thread is all about being picky, I have to point out that gravitational force has nothing to do with magnetic force.

 

[SteveAD]

OK, how's this?

Positive bouyancy= uppity
negative bouyancy=downity
neutral bouyancy=stoppity

 

[Bismark]

Nerds dive?? Who knew???

 

[eponym]

Forgive me for being picky, but since this thread is all about being picky, I have to point out that gravitational force has nothing to do with magnetic force.

Picky? Not nearly. Picky would be insisting that gravity is not a force at all . . .

Einstein's theory gave a correct prediction for the perihelion shift of Mercury. It also explained why objects fall independent of their mass: they all follow the same straightest possible line in curved space-time. Finally, in Einstein's theory the instantaneous gravitational force is replaced by the curvature of spacetime. Moving a mass causes ripples to form in this curvature, and these ripples travel with the same speed as light. Thus, a distant mass would not feel any instantaneous change in the gravitational force, and special relativity is not violated. [from material at the Univ. of Winnipeg web site]​

No, I'm not an astrophysicist, but I did read "Goodnight Moon" to my granddaughter last night.

-Bryan

 

[JeffG]

Nerds dive?? Who knew???

They do? This is all I see.

 

[maged_mmh]

They do? This is all I see.

that stuff comes in other colors?

 

[Brian Sharpe]

Nerds dive?? Who knew???

 

[scuba_smith]

Hey, your physics are pretty good on thos one, with one exception: Gravity. You define gravity as "the 'downward' magnetic pull of the Earth on any object with Mass." While gravitational pull is exerted on any object with mass, it is certainly not a MAGNETIC pull. Gravity is the natural force of attraction between any two objects which have mass. A magnet has the property of attracting certain substances, such as iron. Magnetism describes that attraction.

I do, however, appreciate your descriptions of buoyancy. It is 100% true that an object cannot be "negatively buoyant."

 

[ianw2]

And then, of course, there are those who say that there is no such thing as gravity; the earth just sucks.

 

[MattC007]

I don't usually say positive, negative, etc, I just say whether it floats or not. Does it bother you when people say nuculear instead of nuclear too? I HATE THAT