Am I really weightless ?

[SNorman]

I think you mean you are not MASSLESS. If you put a scale under you, it would not measure anything if you are neutrally buoyant, so you ARE weightless.

Sorry, but can't help you with your numbers (apparently not a "Typical Male diver" at 205lbs). But with a 6.5mm semi-dry suit and full gear (Al80), I need about 34lbs, I think.

marky-d

You're definitely not weightless, you are pushing down on the water with the amount that Earth's gravity exerts on you. The water itself, while "neutrally buoyant" also has weight, that's why pressure increases as you go deeper and can be measured with a pressure gauge, the equivilant of a scale to tell you how much everything above you weighs.

As for the question - what in the world are you trying to figure out? We already know the diver's weight vs. buoyancy can be equalized, otherwise we'd all sink to the bottom of the ocean. If you're really trying to figure out what I think you are, you're going to need volume as well, otherwise I don't see this going anywhere.

 

[Blackwood]

and
duct tapeing bathroom scales to someone and tossing
them out of an airplane.

Doesn't have to be duct tape

 

[FishOutUvH2O]

This thread has gotten hilarious. Not to be offensive or condescending, but some of you have way over-thought the term weightless.

If weight = (mass*gravitational acceleration)
Then the only way to be technically weightless would be for either (or both) mass or gravity to equal zero. Highly unlikely.

So, what you're really discussing is the sensation of weightlessness. And about the only way for us Earthlings to experience that is in a free fall.

Now, I won't speak for everyone, but personally, when I'm neutrally buoyant, I may not be going up or down, but I still feel my mass. So, I'm not getting the sensation of weightlessness underwater.

 

[markyd]

I'm not going to try to argue this anymore, since by some of your definitions, it is phyisically impossible to be weightless, as FishOutUvH2O notes.

I'm curious though, what do you mean by feeling your mass?

marky-d

 

[Blackwood]

markyd -

Given the context of the thread (i.e. the topic statement), there is only one answer.

"Am I really weightless" (emphasis mine)

No.

Does it feel like it? Maybe.

You feel your weight by virtue of the reaction forces. When you are standing, you feel your weight through your legs/feet. When you are sitting you feel your weight through your butt. If you jump out of a plane, you don't feel your weight until - as Ian pointed out - you hit the ground.

In the water, I achieve neutral buoyancy by virtue of gas in my wing since I don't displace enough to equal the weight of my body and gear without it (with the caveat that this depends on the exposure suit I'm wearing). I feel my weight through the straps connecting the wing to my body as I am hanging from them.

 

[FishOutUvH2O]

I'm curious though, what do you mean by feeling your mass?

marky-d

I'll give just one example, the one I feel when I'm neutrally buoyant in a horizontal position facing down with my back inflate BC.

I can feel the sensation of my body being pulled down. In essence the feeling of hanging from the BC, the BC holding me up, or my body being pressed against the BC straps. Whichever way you want to look at it. Pretty much the same answer as above.

 

[Hoomi]

Does this discussion make my mass look fat?

 

[FishOutUvH2O]

Does this discussion make my mass look fat?

Ya know, your buoyant attitude in such a weighty discussion makes me think you just don't understand the gravity of the situation!!!

 

[Hoomi]

Ya know, your buoyant attitude in such a weighty discussion makes me think you just don't understand the gravity of the situation!!!

Well, you know me - just drifting from topic to topic, at the whims of whatever the current trend is.

( <-- me )

 

[Belce]

Actually when you are in the water and achieve neutral bouyancy you are weightless, just like you would weigh 1/6 of your weight here if on the moon. It is your mass that will not vary regardless of where in the water column or on the moon that will not vary.

In metric units of mass are grams and in the Imperial system mass units are slugs.