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Or are you saying _everything_ is conserved, not just energy?


YES !! twist twist twist ... but maybe Im just untwisting something that was previously twisted up in a knot.

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No. Even with the applied pressure, there's still the same pressure gradient caused by gravity. They didn't even make your claim in the video. Maybe there's a hole drilled up the middle of the wooden(?) floater?

If the pressure gradient dissapeared, then any floating thing would sink, including the air at the top of the bottle!

Galileo's Thermometer


A beautiful instrument, known as a Galilean thermometer, relies on buoyancy to measure temperature. The device consists of a sealed vertical glass cylinder mostly filled with a clear liquid. In the liquid are colorful glass bulbs, each having a precise density and a tag indicating a particular temperature. As the temperature changes, the glass bulbs rise and sink. The temperature is read by looking at the tag attached to the lowest floating bulb.

if the temperature increases , the pressure also increases.
that is why the above thermometer works.

there is no air being compressed inside the bulbs as a result of the fluid pressure inside the cylinder.

the pressure inside the bulbs increase due to the temperature inside the bulbs.

the only changes are the temperatures and pressures inside
the thermometer.

and of course the bulbs moving up and down with the changes.


Like a Cartesian diver, or any other object in a fluid, the only factor that determines whether an object will float or sink is the object's density in relation to the density of the fluid displaced by the object when submerged. If the object's density is greater than the density of liquid displaced, the object will sink. If the object's density is less than the density of liquid displaced, the object will float. If the object and liquid have the same density, a condition called neutral buoyancy, the object will remain suspended at a certain depth without rising or sinking. Neutral buoyancy is achieved by fish, sunken logs, scuba divers and submarines.


here is a image that describes the effect of decreasing and increasing density of a fluid and a given object.



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No. A submerged submarine isn't in stable equilibrium. It's either sinking or floating. They have to continually adjust the bouyancy to maintain a fixed depth hydrostatically.



why ?

does the pressure outside constantly change?
does the weight of the submarine constantly change?
does the gravity constantly change?

why would they need to adjust anything when nothing outside the sub changes?



3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.