energy derived from differential specific gravities?

News will tell you. Just wait

Is he in the Union?

Why so patient? Are *you* in the Union?

...Work you did against gravity when you first lifted the water and the oil into the pipe

You'll need to know a lot more.

What is the viscosity of the oil and of the water, the temperature of the system, the surface energy of the oil/water interface, the diameter of the gate valve, and so on...?

For example, below 0° C the water won't flow unless you have several hundred feet of it (a glacier), and then only very slowly.

Best set up the experiment and *measure* it.

See Archimedes about that one. He is the Principle authority on buoyancy.

Tom Davidson Richmond, VA

How about a big pipe created going out into space? It removes all the pollution of the Earth, it pumps it right on out there. What principle does it use for power?????

The venturi effect.

Thank you. No applause, uh save it for the end.

- Don

2) Crossposters suck.

Vaughn

Same place the energy comes from if you lift a weight tied to a rope and let it drop. Result is a net loss in energy. You spend more pumping the stuff than you get back from the generator.

Harry K

dances_with snipped-for-privacy@yahoo.com thought carefully and wrote on 9/26/2005

You physics guys always crack us mechanical engineers up. Keep these jokes coming.

Lance

When you pump water up a pipe, you provide it with potential energy. When it flows down again, it hands back that potential energy that scales like m.g.h

What is the upward force on the blob of oil? The force is equal to the weight of water that the oil displaces, less the weight of oil. This is effectively, an upwards acting weight, called buoyant force.

However, the speed at which this oil blob moves is conditioned by the resistance of the container, and the counterflow of the water. Think of it reaching terminal velocity quite soon, like a parachute jumper.

Brian Whatcott Altus, OK

Let us imagine the same thing in a more colloquial fashion. I have a glass of water and a glass of beer. As the bubbles form in the glass of beer and rise to the surface, they pass through cleverly designed baffles and turn a wheel and generate electricity.

Wait... Here's a better one. I have a box of concrete and a box of cereal on a railroad car. As the cereal in the box settles, it displaces air between the flakes, which rises and, passing through cleverly designed baffles, turns a wheel and generates electricity.

Where, oh where, does this energy come from?

PD

Where do the glass of water and the box of concrete figure in anywhere?

Why not have an generator produce power for an electric motor, which runs the generator, producing perpetual motion?

Or have a propeller on an air boat blow into a sail on it.

One county fair had an elaborate demo of perpetual motion, a vast array of gears and wheels visible to the public. Behind the curtain was a guy turning a crank.

The only thing that apparently is infinite is the human ability to produce memes and debate them.

So far, it looks like everyone's missed the mystery--that the second pipe releases more energy than the first...

Nick

No that's not what happened. While you were waiting 3 months the bottom of the pipe with water corroded and when you open the gate valve the extra weight now causes the bottom to drop off so all the water runs down the pipe. Now the mystery is why is the floor wet?

-jim

wrong:

No it doesn't. You are stopping the experiment too soon. It is true that some energy will be released when the oil floats to the top. But the experiment is not over until you release all of the fluid from both pipes. Then you find that the second pipe with oil at the top releases less energy than the one with water all the way to the top.

Loren

Being 'lighter than water' means it takes less energy to push it uphill. But oil is often more viscous than water, meaning it takes more energy to make it move through a pipe at all. Pumping *any* real liquid is a combination of overcoming potential energy differences, changes in velocity, and viscous friction.

You could extract more energy from the first pipe if you didn't bother to fill the space below the gate valve. You've put the same amount of energy into the water above the gate valve in the first pipe as you have put into the water above the gate valve in the second pipe.

But putting water below the gate valve in the first pipe has made it so you can't recover any of the upper water's energy by merely opening the gate valve. The energy isn't 'gone anywhere', you just have to change the system in order to recover it (e.g. let the water out of the bottom chamber).

Putting oil below the gate valve in the second chamber has made it so at least some of the upper water's energy is recoverable by opening just the gate valve. Not as much as if the lower chamber were empty, but at least some.

The bouyant upward force is equal to the difference in density of the oil vs water times the volume of oil (several ways to calculate the bouyant force on the oil). But how fast this oil moves is a function of that force, the viscosity of the oil (varies with temperature and oil properties), the size/shape of any nozzle/baffles you have.

If the viscosity is relatively high, you can get into what's known as Counter-Current Limiting Flow (CCLF). That's the phenomenon that limits how fast an upturned bottle of water will drain out (flow through the neck alternates between air bubble up, and water slug down). In your case it could be 'oil slug up', followed by 'water slug down'. But this can be avoided by the judicious placement of a separate 'up' flow path and 'down' flow path.

daestrom

He forgot to mention the pumping is very slow, with no viscosity loss. Nick

So I assume you are a ultra billionair by now? No? What a surprise.

Harry K

A "Coriolis motor"? Well, I hate to break it to you, but that's not perpetual motion. It's just converting the rotational energy of the earth into fluid energy. And the rotational energy of the earth is limited. Even if the earth was a solid, perfect sphere of iron with no internal rotational losses, the energy you're converting into fluid energy with that motor would slow the earth's rotational energy as a function of C*e^-r*t. Not only that, but your motor is converting the earth's rotational energy at a horribly inefficient rate. If you want to tap the earth's rotational energy, you'd be better off with a rotating generator with its axis perpendicular to the earth's axis.

Dave

The second pipe released energy because energy was stored in it to begin with. When I lift a rock up above my head, that's potential energy. When I lift water up to the top of the pipe, it's ALSO potential energy. You can't ignore the energy you put into the system to begin with (i.e. hauling water to the top of the pipe).

Dave