Have I found the world's first endless source of energy?

Femme_physics

The floats, thanks to the principles of buoyancy, will keep ascending, maintaining the rotation of the wheel, thus achieving the world's first neverending source of energy!

Or, perhaps, there is a catch? ;)

jedishrfu

how will you prevent the water from leaking out of your one-way valve? :-)

I think the friction at that point will counteract any energy.

There's a historical scam I saw recently called the Keely machine (mysteries of the museum show on US cable) for intersting reading:

http://en.wikipedia.org/wiki/John_Ernst_Worrell_Keely

It was later found that he had a pump hidden in another room powering the device.

Femme_physics

The valve is made out of rubbery or rubbery-like material that only allows the floats in. Leaking is not a problem.

We reduce friction by using the right materials, as long as we have an endless source that generates energy friction should not be an issue.

K^2

Easy enough with some modifications. Make floats cylindrical. That would allow constant aperture at the bottom of container. Replace valve with a mechanical iris that opens and closes almost instantly as necessary. The friction in the iris can be reduced arbitrarily, making it work without losses. The control could be electronic. Again, power consumption can be made arbitrarily low.

So the construction is absolutely possible. That's not the problem.

The problem is that the float only floats when surrounded by liquid from all directions. What happens to the float that's passing into the container through the iris? Well, it experiences full pressure of the fluid from above and none from below. The net force will be down. It's very easy to show that no matter how many floats are in the fluid above it, the downward force on the bottom float will always be greater. (To fit more floats, you need a higher water column, resulting in higher pressure on bottom float.)

The conservation of energy actually becomes immediately apparent if you try to figure out how much work you need to do against the float to push it into the fluid through the bottom valve/iris. The amount of energy needed to take the float from outside and put it at the bottom of container is exactly the same regardless of whether you force the float into liquid from above or from bellow. The difference of potential energies in two situations is exactly the same, and so the energy requirement is the same regardless of path.

Long story short, the machine can't work, which really shouldn't be a surprise.

Femme_physics

Well done!

Truth is my teacher gave us that riddle in class to see how well we remembered hydraulics (turned out we didn't, heh), I just thought it was cool and wanted to have the full explanation written down, so I decided to post it here in the fashion that I did

Thanks for playing along and for providing it

K^2

If you don't mind me asking, what language is that, besides English and Russian?

Femme_physics

That would be Hebrew :) Me and my friends are trilinguals. I keep that paper to pose that question to those who only know one of those languages.

K^2

I also have some trilingual friends, and they would be upset with me for not recognizing it.

jedishrfu

I recognized the font and can understand every language known except Greek :-)

Integral

Yeah, me too, they are all Greek to me.

jedishrfu

Ba-dum (drum roll for the closed captioning service)

berkeman

Please re-read the Rules link at the top of the page. There is a section on banned topics, and they include discussions of perpetual motion machines (PMMs).

Thread is locked.

berkeman

BTW, here is the text from the Rules link that lists PMM discussions. Note the helpful links which you can use to answer your schoolwork question on this banned topic: