Quick explanation of how I think it works:

Initially, a very small electrical potential difference between the buckets is caused by the photoelectric effect of the light shining on C. This "seed" potential difference is multiplied thousands of times by the following chain reaction:

A is positively charged and B is negatively charged. Therefore more electrons in the source water will exit at the A dripper, so the water falling through A will be negatively charged and the water falling through B will be positively charged. The negatively charged water from A falls to D which is connected to B and reinforces B's negative charge. The positively charged water from B falls to C which is connected to A and reinforces A's positive charge.

The energy for all of this must come from the gravitational potential of the source water. Gravity pushes the charged water against the electrical potential gradients from A to D and from B to C

Close, but not quite.

Every atom has a tiny tiny charge associated with it.
This system is essentially a positive feedback capacitor, that takes advantage of the flux effect of charged particles (ie. an EM field) passing over a conductor, to slowly build up a charge in the system.

Once the charge is large enough, the random distribution of the charge within the system is what creates the diffusion of the water dropping through the buckets.

Once the charge is large enough, it overcomes the distance barrier between the two balls and redistributes the charge back into the water.

Its basically a van-de-graffe machine, only in a really novel way.

They are called Kelvin water droppers / batteries.

He likes to say how many volts this thing builds to, but what kind of Amperage? Are we talking about fractions of microamps? It appears that most of the gravitational potential is absorbed by the buckets, but how much is converted to charge?

If you have a source of falling water this is certainly mechanically simpler then something like a water wheel, but how much less efficient is it? Could this interesting quirk of physics ever be put to practical use?

>> ^dgandhi:
He likes to say how many volts this thing builds to, but what kind of Amperage? Are we talking about fractions of microamps?


Very very small. It is not even remotely efficient.

Why did you downvote my comment ?
This has nothing to do with gravitational potential energy at all, its purely the interaction between positive and negatively charged water particles passing through a conductor to build up charge.

Zero kinetic / gravitational potential energy is converted, the meer useage of gravity is a neat way to get the water droplets to pass through the rings, but none of this energy is converted into electrostatic energy.


Edit: A more detailed description can be found here.
http://amasci.com/emotor/kelvin.html

Sorry to burst the bubble, but this is a dupe:

http://www.videosift.com/video/10000-Volt-Arcs-Created-by-Falling-Water-Droplets

Every atom has a tiny tiny charge associated with it.

Actually, over 99.9% of the water particles in a bucket at 20,000 volts have a neutral net charge, because charge is quantized. If every water particle had an extra electron, it couldn't even condense to form a liquid.

flux effect of charged particles (ie. an EM field)

An electrical potential gradient is a more specific term for the kind of EM field present in this problem. The magnetic component is negligible.


Once the charge is large enough, the random distribution of the charge within the system is what creates the diffusion of the water dropping through the buckets.

You mean the positively charged water molecules repel other positively charged water molecules, etc.


Its basically a van-de-graffe machine, only in a really novel way.

A Van De Graaff machine is based entirely on surface friction, while this is based on electrostatic induction.

Zero kinetic / gravitational potential energy is converted, the meer useage of gravity is a neat way to get the water droplets to pass through the rings, but none of this energy is converted into electrostatic energy.

Even the site you linked contradicts you and agrees with me on this count. The energy for the sparks comes from the gravitational potential of the water in the source, since gravity does work to pull the positively charged water away from the negatively charged bucket and towards the positively charged bucket, etc.

d'oh

*discard

Discarding this post - discard requested by original submitter jwray.