I think I read your post wrong, I just said the same thing you did. I bad.
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What is the effect on gravity underwater?
- Thread starter Kim
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Just wait and see what happens if Walter disagrees againradinator:
jonnythan,
Actually, I agree with your illustration (although without an experiment, it'll be impossible to tell what would actually happen - volunteers?), but that differs from an unmutilated body suspended in the water. In your example, you no longer have a closed system. Water pressure and buoyancy can now act directly on the circulatory system (it has limited or no effect if the system remaims closed) which changes everything.
Actually, I agree with your illustration (although without an experiment, it'll be impossible to tell what would actually happen - volunteers?), but that differs from an unmutilated body suspended in the water. In your example, you no longer have a closed system. Water pressure and buoyancy can now act directly on the circulatory system (it has limited or no effect if the system remaims closed) which changes everything.
The point is that whether the body is living or not is irrelevant to the physics involved. The body has all sorts of ways to *overcome* those physics, but the point is that in the water, there's no *tendency* for the blood to flow downward that the body has to deal with.Walter:
Being in the water, in any orientation, is more akin to lying down, and position won't matter to "gravity" as referenced in the original question.
novadiver
Contributor
HMMMM ,blood pressure, yeah that's the ticket, " blood pressure varies from person to person and even in differant parts of your BODY , for example, IT IS HIGHER IN YOUR LEGS THAN IN YOUR ARMS " page 382 american medical association , family medical guide, so DR. jonny does this reflect your medical training?jonnythan:
jonnythan:
I understand this is your belief. I don't understand why you believe it. Have you seen any evidence to indicate this is the case? Simply repeating it doesn't make it so.
novadiver
Contributor
Maybe if he could quote some source info we could all find out together.Walter:
That would be helpful.
I don't understand why you don't get it. Perhaps someone else can do a better job explaining?Walter:
Maybe it will be easier if you understand that the human body is not rigid. The *physiology* is irrelevant for the answer to the original question. The absolute pressure in a blood vessel increases *exactly* as the water pressure around it increases.
When standing on land, there is a pressure differential of ~2.5 psi acting outward between blood in the head and the blood in the feet. The counteracting air pressure acting inward only increases, say, 0.01 psi between the head and the feet. Therefore, since there is more outward pressure from the blood vessels at the feet than the head, the blood wants to flow *down* and *out* because of that pressure differential.
When in the water, the pressure differential acting outward between the blood in the head and feet is still about 2.5 psi because of gravity. However, the pressure differential acting inward between the water aruond the head and feet is also 2.5 psi because of gravity. Therefore, there is *no* blood movement the way there is on land.
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