# Investigating the water-ice electret

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1. Feb 13, 2016

### Robsta

Hello all, I'm going to investigate the properties water when frozen in a strong electric field for a product I'm designing.

A strong field will align the polar water molecules, and then they will freeze. I'm planning to create this strong field with a car battery attached to two parallel plates for my proof of concept. When the battery is switched off, the lump of ice should retain a measurable dipole moment.

My question is, can anybody help me predict what dipole moment it will have and what apparatus I would need to measure it?

I can work out the polarisation density of the water, $$P = \chi _e \epsilon _0 E$$ where $$\chi _e = 79$$ for water. Unfortunately, I have no way of knowing how much of this polarisation will be maintained when the water molecules shift into a lattice in the ice phase.

In any case, the field generated by the polarised ice once the main field is switched off will be small, and I wondered if anybody knows what equipment I should use to detect it? I'd really like to avoid moving parts if possible, but I think that might be hard when looking for an electrostatic field.

I'm an undergraduate physicist and I'm not very experienced with sensors and instruments for detecting E fields.

2. Feb 18, 2016