# Thread: Making a Water Bridge Experiment

1. We can start by using a pair of two beakers, 100 ml, filled with triply deionized water. The bridge needs the clean deionized water to form properly. The beakers are then exposed to a high dc voltage, by putting electrodes into the beakers, one beaker will turn negative, the other positive, we will then see the water form a stable, cylindrical bridge between two beakers by pushing one beaker away from the other. Typically a charge built up to 25 kv can see a bridge formation of nearly an inch.

Nobody is totally sure about how this really works but one possible explanation for how this actually works is the surface polarization on the water surface when a high tangent electrical field is applied causes the bridge to form.

2.

3. Originally Posted by Ascended

We can start by using a pair of two beakers, 100 ml, filled with triply deionized water. The bridge needs the clean deionized water to form properly. The beakers are then exposed to a high dc voltage, by putting electrodes into the beakers, one beaker will turn negative, the other positive, we will then see the water form a stable, cylindrical bridge between two beakers by pushing one beaker away from the other. Typically a charge built up to 25 kv can see a bridge formation of nearly an inch.

Nobody is totally sure about how this really works but one possible explanation for how this actually works is the surface polarization on the water surface when a high tangent electrical field is applied causes the bridge to form.
Most interesting, especially to one who specializes in high voltage experimentation! Your triple deionized water exposed to the air as it is, will be well-ionized within a minute or two of exposure to the air, due to CO2 dissolving in it. The Ph will quickly become ~ 5.2. jocular

Edit: Thus I suspect pure water of Ph 7.0 is not a prerequisite to this experiment's success.

4. Presumably the water molecules attract each other to an extent which prevents gravity from tearing the bridge down. As water molecules are electric dipoles, perhaps the dipoles are being aligned by the electric field in a manner which enhances their tendency to cling together.

5. Thanks for the link, really interesting about the vertical bridges. Also it seems to be suggesting that the bridge formations 'arn't' solid, that only a hollow bridge forms.
Certainly gives more credence to it being a surface phenomena only. Also I'm a bit unsure about whether it states it is possible to maintain a vertical bridge without an AC field or for the first time either a vertical or horizontal bridge is possible using either a DC or an AC field. But either way certainly interesting stuff.

6. Originally Posted by PhDemon
Originally Posted by Ascended
Also it seems to be suggesting that the bridge formations 'arn't' solid, that only a hollow bridge forms.
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I could be wrong (I just skimmed it quickly) but I thought it was saying the polarizing effects were limited to the surface with the interior of the bridge containing "normal" unpolarized water rather than it being a hollow bridge. This being why the polarization parameter (alpha) was low.
Ok cheers I'll have another look and see if I can find that bit, it seems important as the surface effect would then be supporting the entire volume & mass of the bridge which is really impressive.

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