Jack the Bodiless

Incidentally, if you don't trust either myself or that godless pagan Archimedes, you could verify this yourself.

First, assume an inverted vertical position in air: stand on your head.

See how long it takes for you to feel dizzy due to blood pooling in your head.

Then go to a pool where PADI instructors are holding a hands-on "intro to Scuba" event. Ask to try the gear.

Then stand on your head underwater (I suggest you tell the instructors what you're going to do first). You will be able to maintain that position until your air runs out, if you wish. Blood will NOT pool in your head, because at every depth from your toes down to your head, the pressure will increase with depth at the SAME RATE inside and out. The neutral buoyancy of your blood causes it to neither rise nor sink in water.

Therefore there is NO gravity-related effect on blood flow, and your heart can pump the blood in either direction with equal ease.

Incidentally, if you cut your hand underwater, raising it to reduce blood flow will NOT work for the same reason. And if the vertically-floating man in your earlier example had the misfortune to be decapitated by the propeller of a passing boat, the rate of blood loss from his body will not change regardless of whether he remains vertical, keels over, or even flips upside-down. Gravity has no effect on the flow of a fluid within another fluid of the same density.

lpetrich

Does anyone have any idea what technical fields Vanderzyden claims expertise in? That could help in formulating analogies that he can relate to.

Vanderzyden

As with others here, your intense focus on "winning the debate" severely inhibits you from gaining a comprehensive understanding in what is relevant to our discussion. Some of the things you have said are correct, but your ability to "fire your weapon" does not mean that you can hit the target. In fact, you are not even oriented "down range".

In your search for truth, it would seem that you are leaving your flanks heavily exposed.


John

Coragyps

And if that were not true, not a single one of the several hundred oil well cementing jobs that I have designed in the last twenty years could have worked. VZ, you are utterly wrong on this one: give it up.

<img src="graemlins/banghead.gif" border="0" alt="[Bang Head]" /> <img src="graemlins/banghead.gif" border="0" alt="[Bang Head]" /> <img src="graemlins/banghead.gif" border="0" alt="[Bang Head]" />

RufusAtticus

Vander,

Please provide us with your calculations.

Vanderzyden

And your point is what, precisely?

(Yes, I am nearly ready to give up, but not for the reason you apparently think I should.)

Coragyps

My point is that you are doing yourself no good by arguing a position that has been demonstrated to you multiple times to be in error. Wrong. Mistaken. At variance with reality.

If I laid a two-inch Schedule 40 mild steel pipeline from the deepest point in Lake Superior to a point six inches below the surface, how many hydraulic horsepower would be required to pump five gallons per minute from the lower end to the upper?
And how much to pump from the upper to the lower?

Assume uniform temperature and ignore the
compressibility of water.

[ November 06, 2002: Message edited by: Coragyps ]</p>

Jack the Bodiless

...Aha. I suspect that your error is beginning to dawn on you, and you're preparing a characteristically evasive retreat: "Well, obviously buoyancy is a factor, but what I actually meant was..."

Lest we forget what the "target" was, here are the big fat juicy ones I was squarely aiming at:
TARGET IDENTIFIED: "the critical fact of gravity".

TORPEDO LAUNCHED: Gravity has no effect whatsoever on fetal blood circulation.

RESULT: Direct hit.
TARGET IDENTIFIED: "Jack is completely in error".

TORPEDO LAUNCHED: I have made no scientific errors anywhere on this thread.

RESULT: Direct hit.
MULTIPLE TARGETS IDENTIFIED: "The orientation of the fetus does indeed make a difference... ...gravity assists blood down the inferior vena cava... ...gravity assists blood down the aorta... ...If the fetus is horizontal, the pumping load on the heart is significantly reduced".

TORPEDOES LAUNCHED: The orientation of the fetus makes NO difference, the force of gravity is precisely negated by buoyancy of the blood at every point throughout the system, no gravity-induced net force will assist blood flow in either direction along the inferior vena cava or the aorta, the pumping load is identical whether the fetus is horizontal or vertical.

RESULT: Multiple direct hits.
TARGET IDENTIFIED: "Gravitational effects still apply, and they are significant".

TORPEDO LAUNCHED: Gravitational effects are utterly without significance here.

RESULT: Direct hit.
TARGET: Obvious.

TORPEDO LAUNCHED: Yes it does. The external pressure of the amniotic fluid IS the force which counteracts the internal pressure created by gravity acting on fetal blood.

RESULT: Direct hit.
TARGETS IDENTIFIED: "...you are so very much in error with your posts... ...the worst statement you made is..."

TORPEDOES LAUNCHED: I have made no errors, and it IS just as easy to pump up as it is to pump down.

RESULT: Direct hits.
TARGET IDENTIFIED: "No one here has brought physical principles to bear on a refutation or correction of my application of hydrostatic pressure to the fetal CV system."

TORPEDO LAUNCHED: Many did. I did. Many times.

RESULT: Direct hit.


...I believe that I have sunk your battleship, Vander. However, as the force of buoyancy apparently does not operate in your Universe, will you now claim that your battleship is held up by invisible angels and is therefore unsinkable?

Vanderzyden

This is a simple mechanical engineering problem. I will again ask you to persuade me that it is worth the additional investment of my time.

What, precisely, is your point? And, what additional relevance does it have to the design of the fetal CV system?


John

P.S. If you are simply attempting to test me, then you must realize that you are missing at least three elements of information: what are they?

[ November 06, 2002: Message edited by: Vanderzyden ]</p>

scigirl

Ok here is vander's argument again (I think) for why the heart must have been intelligently designed because of gravity:

Hmmm, why does this sound an awful lot like "I walked to school uphill both ways?"

scigirl