A machine to convert gravity to mechanical energy # 2

[mondrasek]

Mondrasek,
Buoyancy is based on displacement not on depth. The amount of buoyancy a object has does not have anything to do with water pressure.

Not True

Buoyancy
From Wikipedia, the free encyclopedia

In physics, buoyancy (BrE IPA: /ˈbÉ"ɪənsi/) is the upward force on an object produced by the surrounding liquid or gas in which it is fully or partially immersed, due to the pressure difference of the fluid between the top and bottom of the object.

Brian, the difference in water pressure at the top and bottom of your cylinders is also equal to the weight of the water they displace.

[brian334]

The buoyancy of a object is the same at a depth of 1 ft. or 100ft.
Or to put it your way, the pressure difference between the top of a submersed object and the bottom is the same at 1 ft or 100 ft.

[mondrasek]

Correct!  The *difference* in the pressure on top and bottom is the same (bouyancy), but both pressures increase as you go deeper, right?  So the force on the bottom side increases as you go deeper, right?  And you must overcome that force to expand your cylinder, right?

I calculated the cylinder diameter that would have exactly 64 lbs of force pushing against it on the bottom at 10 feet deep.  That diameter was 4.454 inches.  I also calculated the length of the cylinder of that diameter that would give the 1 cubic ft of volume you wanted to displace.  That length ended up being 10.02 ft.  But that was rounding error.  It would be exactly 10 ft, exactly the depth you prescribed, exactly equal to the weight in the column of water displaced above the cylinder bottom.

If you take a cylinder that displaces 64 lbs of water and sink it with a weight that weighs 64 lbs it will only sink until the top it is at the exact surface of the water.  No matter what diameter and length combination this will be the case.  And at the bottom, the force there holding the cylinder up will also be exactly 64 lbs.

You want to make the cylinder weigh 65 lbs with an internal weight that is 64 lbs. that displaces 64 lbs.  So it will sink.  But as soon as the top of the cylinder is below the surface of the water the force on the bottom opposing expansion will be greater than 64 lbs.  The further down you go the greater the force opposing the possible expansion.

M.

[ResinRat2]

Hi Brian,

Obviously you believe your invention will work. Who cares what anybody on this forum believes anyway? The only way to really know if it will work is to build it and test it out.

I wish you the best of luck, and I hope it works out for you.

[brian334]

M.
We are not on the same page.