"Paladin" noneofyourbusiness.www wrote in message
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"Gilligan" wrote in message
. ..
|
| "Paladin" noneofyourbusiness.www wrote in message
| ...
|
| "Gilligan" wrote in message
| . ..
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| | http://encarta.msn.com/media_4615415...for_Water.html
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| The diagram proves my point. Since there is no significant temperature
| change involved with a propeller but there is a significant pressure
| change
| then the water does not vaporize because it boils. Rather it vaporizes
| because
| of the pressure change.
|
| I'm just so brilliant. You can't even manage to misdirect me.
|
|
| I can't misdirect you, but I can set you straight.

You've done an inadequate job of it so far...

| When water boils, as in your kettle, those "bubbles" are water vapor
| suspended in the liquid water.

Agreed. But, suspended is a poor word choice. I prefer to call it
water vapor displacing the liquid water.

| Cavitation is caused by the propeller slipping on water vapor suspended
in
| the liquid water.

Quaintly envisioned. Highly inadequate. Cavitation is a descriptive term
used
to describe the vaporization of the water near the low pressure side of
the
propeller blades resulting in over-revving of the engine. The over-revving
of
the engine is caused by the prop losing contact with the water.


| Would it then be reasonable to say that cavitation is caused by water
| boiling?

Not in the case of a boat unless it was in a giant pot of boiling water
on the stove.

| OR
|
| Cavitation can only happen in your tea kettle?

Cavitation could very well be caused by operating a prop in boiling
water but the prop doesn't cause the water to boil. The fire under
the tea kettle is doing that job.

Now, who's straightening out whom?

Suppose I have water in a beaker and place it in a bell jar. The air in the
bell jar is pumped out, lowering the pressure. Eventually the water begins
to boil.

Where is the heat source causing it to boil?