help fix my Lord Kelvin thunderstorm

Only things I can suggest, use styrofoam instead of the boards and turn on the air conditioning to dry out the air. (don't know where you are) Mikek

trying to learn the kids (via discovery) about electricity and how to generate etc..

We were working through static electricity, rubbing various items like a poly fur blanket and produce visible sparks. This led them naturally to, "hey that looks like lightening", to how it works and can we make static elec with water droplets and air which led us to lord Kelvin thunderstorm machine

so we cobbled together the materials to make it : 2 Campbell soup cans bottom and top removed, 2 all-metal paint cans (clean), 14 gauge zinc coated steel wire , round nickel ball/sphere ( brushed nickel cabinet handles), long threaded screws, nylon tubing and plastic bucket.

It is the standard configuration as shown on web but i can not get any action out of the device ?

Each of the two metal paint cans have 4" threaded rod protruding from the can's handle nub and tipped with polished metal ball , the 14 gauge steel wire has a big loop inside bottom of the paint can and a small loop tightly fitted around a soup can. the paint cans are positioned (apart) so that there is a small (5mm) gap between the metal balls. The wires are fashioned so a soup can is over the opposite metal paint can and paint cans on top of dry board. The water is set to drip through center of soup cans from one source and it never seems to make any static elec.

Diagnosing:

• i have tried to touch just one of the paint cans to create an imbalance , no electrical sensation, no action

• tried to inject some charge by using the poly blanket trick and a spark jumps between finger and the one can I touch.

• tried hanging a piece of thread near the spark gap to see if there is any attraction , None

any hints or things to consider diagnosing would be greatly appreciated. thanks robb ======================================================

Perhaps the video of a working model will help. Is your drip fast enough?

-- Lord Androcles, Zeroth Earl of Medway

The water passing through the cans must be in droplets not a solid stream.

The passive cans should be suspended via the cross conductors, this means you may need to use brass tubes so you can solder to the cans. The catch buckets need to be insulated between each other. This can be done by putting a sheet of lexan or something non conductive and thick under the buckets or, place them inside larger plastic pales for example.

Basically, the passive cans and catch cans need to be electrically floating and the water stream in the passive cans should be in a broken stream.

Jamie

The water stream has to fragment into droplets *inside* the cans.

IOW, the water must enter the cans as a continuous stream and leave the cans as separated droplets.

Adjust the water flow rate until this condition is achieved.

also, it should break into droplets inside the tubes (soup cans)

zinc plated steel solders easily (eg: paperclips), galv is a litle harder. anyhow solder isn't needed, wrap the wire round them then tighten it a bit.,

but yeah, rigid wires will work better, 3mm tie wire is probably about right. dunno what that gauge is in American.

stand them on clean glass supports. (jam jars, glasses, or bottles)

no, it must break inside the tubes.

--


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Thanks to all helpful replies,

Yes, i did view the video and many others similar to that one.

It all looks dead simple and probably is. BUT, mine was/is not working so well. I can get an occasional spark but not regular.

My setup is not far off that video, my support wire for the drop cylinders is not welded to outside of the water catch can. Instead, the wire is passed through a hole i punched in the lip of the can, the wire forms big loop that sits inside the bottom of can. The other end of the wire sticking up out of the catch can is looped around my soup can drop cylinders.

I do not have good control of the drip rate (yet) so it takes alot of effort to get the drip running as suggested.

Things i tried that helped some ?

1. The soup cans had a thin clear coat on the outside i was un-aware that gave infinite ohm reading on surface. so I sanded it off.

1. The inside of soup can has a gold valFlex coating that i could not remove chemically with (acetone, mineral spirits / naptha, brake cleaner( tolulene-hexane-etc), ammonia, isopropyl-91% ) and sanding was too much work.

2. So just Covered cans with aluminum foil.

1. I replaced orb electrodes with pointy electrodes for the spark gap.

2. I wrapped the (wire to can) joints with aluminum foil to ensure contact with outer catch cans

1. I installed a static meter (strip of paper and strip of sewing thread) to outside of catch cans to indicate a charge is building

2. I held the water drop tubes in each hand and adjusted up and down till i saw a charge building via the paper strip

1. Put water catch cans on top of a plastic bucket

Final results were...

Many times I had to inject a charge on one of the cans to get it working (i.e. build up charge on me and touch one can until the paper static indicator rose some). It would never just start charging on its own. Then if i got the water stream at just right place it would slowly charge (slow raising static paper strip). The paper strip would rise to a certain point then start fluttering and bouncing a small bit and i would occasionally get a spark on the spark gap. When i get a spark the static indicator paper would drop way down and start slowly rising again. Since the static indictor paper is bouncing up and down just before the spark level I am guessing i have HV leakage somewhere ?

but where ? what would be cause of the leaks ? sharp edges ? Moisture in air ?

anyway thanks, i appreciate everyone's time for all the helpful replies. robb

"robb" napisal w wiadomosci news:QYudnSh6SPE-O27PnZ2dnUVZ snipped-for-privacy@earthlink.com...

generate etc..

poly fur blanket and produce visible sparks.

works and can we make static elec with water droplets and air which led us to lord Kelvin thunderstorm machine

The Kelvin's generator is not for kids. In our schools was presented the simple generator consists of three parts.

1. Water droplets "producer",
2. A metal plate with the surface covered with fat,
3. A metal container

The droplets are rolling on the surface to get the electrons. The plate should have contact with the Earth. The sparks are jumping betweein the container and the ground.

Kelvin's generator is very sophisticated.

The simple one is the pure physics. The Earth has voltage about 200V. The capacitance of smal drop and the big drop (container) is proportional to their surface (r^2). The mass is proportional to r^3. The voltage is V = Q/C

In our generator Q is constant but the capacitance of the big drop (container) is smaller than the sum of the capacitance of droplets. S*

This is the key to the whole device. Everything else is not that critical.

A continuous stream *must* fragment into droplets *inside* the cans. (Do you understand why?)

Adjust the flow until this condition occurs. You may even need to construct some nozzles to allow better control of this.

Thanks for the help,

well i think i understand now in my amateur mind ... that the charge imbalance on the upper cans causes a repulsion or attraction to electrons in the water stream as it approaches the upper cans which is the reason for a surplus or deficit of electrons in the individual droplets as the stream fragments. So, there must be an optimal position relative to the attractive/repulsive forces one would want the water stream to fragment and realize the max/min charge of the attracted/repulsed electrons.

I agree i will then need to get a nozzle of some sort to control the stream fragmentation height, currently it is dripping out of a 3-4 mm ID nylon tube and the stream to fragmentation distance fluctuates *alot* as it runs.

thanks again for the time and help robb

If you can't control the fragmentation point, then you might want to try a variation with grounded nozzles:

Thanks for idea,

Have any links to resources for fatted flat plate static generation ? I see oodles of "water drop static" googles for lord kelvin device variants but none as you describe

I like your device idea and i want to build one but I am not convinced that simplifying the mechanics of the device while adding the concept of ground and earth connections decreases the sophistication of that device.

kids/people seem to digest simple concrete concepts (in small incremental steps). The lord kelvin thunderstorm, in all its technical sophistication, has a certain concrete and tangible containment that lends itself to simple incremental revelations with the observer's cognition.

thanks again, robb

The Kelvin generator depends on a myriad of subtle concepts that can confound even a sophisticated observer. The production of charge is the result of both complex induction and gravitational energy, while the initiation process depends on uncertain and uncontrollable environmental factors (cosmic rays, atmospheric ions, etc,)

Although it may have an immediate dazzling effect on most people, I would claim that it has little overall pedagogical value.

If you want to dazzle while presenting simple, incremental, and controllable ideas, you may want to consider building an electrometer to visually demonstrate the ubiquitous presence of electrical charge and electrical fields. Here are some links:

(scroll down to middle)

you removed the part about "i am not convinced" which is why i wanted to build your example device so that i might convince myself. It was an honest and sincere request to experiment with the simpler water drop static generation device.

I could not find an example of the device you mentioned in my web searches, did you forget to add the link ?

all those subtle confounding concepts surely have some important value for teaching you obviously learned them

I do not see how concrete and tangible translate to dazzling. You think dazzling has no place in pedagogy either ?

I suppose you are making a joke here ? as jfet and integrated circuit operation hardly falls in the realm of obvious

else you would have mentioned electroscope

besides we made a crude electroscope using a piece of tissue paper and sewing thread to visually demonstrate presence of electrical charge it certainly satisfied your dazzling metric at least the kids were dazzled.

If you have a link to the device you mentioned or the device name or the originator's name, i am truly interested to look it up.

Thanks, I do appreciate your helpful replies, robb

"Regular foil-leaf electroscopes deal with electrostatic potentials in the range of many hundreds or thousands of volts. The above device can detect one volt. Its sensitivity is ridiculously high". Lord Kelvin had the electrometer with the 160 marks on ONE volt. S*

>

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The fat is necesary to keep the droplets as the sphere.

Ten years ago it was described as the "electrostatic experinent". Now I could not find it.

Kelvin wrote about "Multiplication of charge". To be precise there is the multiplication of voltage.

If the droplets are joining together the voltage is rising. It take place in the clouds.

So, the simply device is the cloud. The sparks jump to the Earth.

The only problem is how to charge the droplets. In the clouds they are charged. (Because they levitate in the Earth electric field).

You must do it by the "induction" or by contact. Unfortunatly I do not know who invented the fatted plate. But the device was produced for schools. Now the Van der Graff is offered. S*

>

It sounds like the wet analogue of a Van de Graaf generator, while Lord Kelvin's is the wet analogue of Wimshurst's machine,

--
Neither the pheasant plucker, nor the pheasant plucker's son. 


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Robb wrote: "If you have a link to the device you mentioned or the device name or the originator's name, i am truly interested to look it up".

May be that the device was originated by Soviet Union, because almost everything produced in Poland was Soviet's licence.

Have you heard in your country about the drop generator with the hydrofobic surface? S*

that's a MIT article from last year.

Ah, soviet technology. that could explain why I haven't found a description of that device written in english.

--
Neither the pheasant plucker, nor the pheasant plucker's son. 


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Russia science is the best. But it will be the MIT's discovery. S*