Electrical Resistance of Water

[FionaZuppa]

"Insulator" implies it doesn't allow current flow. It does. So technically, it's a 'semi-conductor'.

Pure water is a super good insulator. No free trons to be had.

Conductivity is very low
Ultra pure water 5.5 x 10e-6 S/m

1/S is the resist units

 

[480sparky]

Pure water is a super good insulator. No free trons to be had.

Oh, there most certainly is. Not many, but they're there.

 

[FionaZuppa]

Oh, there most certainly is. Not many, but they're there.

You a betting man?

referring to pure water, the answer is No. Explanation: Water is an covalent molecule with two Hydrogen atoms attached to Oxygen atom through a covalent bond. So water has no free electrons

 

[LarryFine]

"Insulator" implies it doesn't allow current flow. It does. So technically, it's a 'semi-conductor'.

Technically, semi-conductors are made of insulators with "impurities" intentionally added to make them, well, semi-conductive.

 

[FionaZuppa]

Technically, semi-conductors are made of insulators with "impurities" intentionally added to make them, well, semi-conductive.

Somewhere in the middle of zero ohms and infinite ohms, is a semiconductor.

Yeah, even semi's leak though.

I guess with large enough e field you can strip trons off of H2O and as soon as one leaves another tron will jump in. A vacuum is a good insulator, until there's enough force in e field for trons to jump across the vacuum.

Always a way, just a matter of how much force is needed to make it happen.

A water as a liquid dielectric in a capacitor? That's down right crazy......

 

[mbrooke]

He stole it from Tom. I know 'cuz I read it on the internet.

Maybe- but around the time of the revolutionary the internet had not been well established in the North American colonies. Not to mention what little IT there was ending up being destroyed during the war.

 

[mbrooke]

One of the most intelligent members here is Gar and he regularly references Wikipedia.

Gar is only one Genius. You are forgetting about Mivey, Smart, Roger, Donr, Romex Jockey, Iwire, Dennis Alwon, 480Sparky, hbiss, GoldDigger... all whom seem to avoid it.

 

[GoldDigger]

I avoid citing it for controversial issues, but I use it for general background information, and like others I use the cited sources from relevant Wikipedea articles.

 

[mbrooke]

I avoid citing it for controversial issues, but I use it for general background information, and like others I use the cited sources from relevant Wikipedea articles.

I wouldn't even use it for background information. It takes on error to steer you down the wrong path.

 

[mbrooke]

Pure water is a super good insulator. No free trons to be had.

Conductivity is very low
Ultra pure water 5.5 x 10e-6 S/m

1/S is the resist units

Siemens? You da man!

 

[winnie]

Pure water has a small amount of disassociation going on where you have a very small quantity of OH- and H3O+. These ions allowca tiny bit of ionic conductivity.

This small amount of disassociation is where you get the pure water pH of 7

Metallic conductors are those where there are electrons completely free to move through the material even in the 'ground state'.

In insulators all of the electrons are tightly bound.

In semiconductors there all the electrons are tightly bound in the ground state, but there is a conduction state available at very low energy, so that simple thermal excitation results in conduction electrons.

Jon

 

[mbrooke]

Pure water has a small amount of disassociation going on where you have a very small quantity of OH- and H3O+. These ions allowca tiny bit of ionic conductivity.

This small amount of disassociation is where you get the pure water pH of 7

Metallic conductors are those where there are electrons completely free to move through the material even in the 'ground state'.

In insulators all of the electrons are tightly bound.

In semiconductors there all the electrons are tightly bound in the ground state, but there is a conduction state available at very low energy, so that simple thermal excitation results in conduction electrons.

Jon

Ground state? What is this?

Electrons tightly bound, doesn't everything start conducting at some voltage? Even porcelain begins to look like copper?

 

[winnie]

'Ground state' is the energy level of an atom, molecule, or larger assemblage when it is at lowest energy; in this case talking about electrons in orbitals.

Think about ordinary hydrogen. 1 electron, 1 proton. Apply enough energy and you can rip that electron completely away from the proton. The amount of energy needed to rip that electron away depends on how much energy it had to start with. But there is a lowest energy orbital that the electron can be in, called the ground state.

As more protons and electrons are added to an atom, the different possible orbitals get filled up in order of lowest energy to highest. In general the electron in the highest energy state is the one available to move around. (Glossing over lots of details that I don't fully understand. You too can be a quantum mechanic!)

In a dense material like a solid (as opposed to a gas) the orbitals of the individual atoms blend together, and you should really think in terms of electron energy bands.

In a metal, the 'highest occupied energy band' is only partially filled. This means that only a smidge of energy is needed for an electron to move into a free state and move around.

In an insulator, the 'highest occupied energy band' is completely filled. For an electron to move around a large amount of energy needs to be added to rip it from the occupied band into an energy band where it can move around. Apply enough energy (say in the form of an intense electric field, or bombard things with high energy particles) and yes, you will get current flow. I don't know if porcelain will ever 'look like copper', because the energy needed for getting electrons to flow might be so much that you've vaporized the material and now have current flowing through an arc, but apply enough energy and you will have conduction.

In a semiconductor the 'highest occupied energy band' is completely filled, but an un-occupied band is available that isn't much higher in energy. This means that things like the random thermal energy of the electrons in the material is enough for some of them to be in an unoccupied band where they can move.

-Jon
In a metal 'open' electron states are available right next to occupied electrons states, so the electrons are really really free to move.

In a semiconductor, there are well defined energy ba

 

[mbrooke]

Thanks- I just got scarred... I hope people do not equate this with electrical grounding.

 

[FionaZuppa]

Pure water has a small amount of disassociation going on where you have a very small quantity of OH- and H3O+. These ions allowca tiny bit of ionic conductivity.

Jon

Although true, the ions are not part of H2O. You can make "pure" H2O more pure by exposing it to an electric field where the ions then move to the appropriate polarization, thus removing them from the H2O water.

In just terms of H2O (no ions), it's a very very very good insulator. Some high voltage apps will use a "pure water" capacitor (even with the pure water ions in there).

Pure water (even with the ions) is a "corrosive" liquid to many other materials, so it's use needs to be engineered with care.

4 types of "pure" water per this ASTM

Standard Specification for Reagent Water

www.astm.org

 

[paulengr]

"Insulator" implies it doesn't allow current flow. It does. So technically, it's a 'semi-conductor'.

No. Well below semiconductor conductivity.


Sent from my iPhone using Tapatalk

 

[paulengr]

You a betting man?

referring to pure water, the answer is No. Explanation: Water is an covalent molecule with two Hydrogen atoms attached to Oxygen atom through a covalent bond. So water has no free electrons

The hydrogen ions dissociate into hydroxyl ions (OH- and H+) spontaneously in small amounts. At pH 7 you have roughly 10^-7 concentration of both. It’s in the definition of pH.

 

[paulengr]

Technically, semi-conductors are made of insulators with "impurities" intentionally added to make them, well, semi-conductive.

Carbon, silicon, and various mixtures such as GaS, SiC, TiN, etc. are all semiconductors by themselves. Doping actually reduces electron (hole) mobility even as it increases or decreases electron charge (+ or -) by the addition of phosphorous or arsenic.

 

[winnie]

Although true, the ions are not part of H2O. You can make "pure" H2O more pure by exposing it to an electric field where the ions then move to the appropriate polarization, thus removing them from the H2O water.

I'd love to learn more about this. I always understood this disassociation to be an equilibrium process, meaning that if you had H2O present then you would have the ions present and that Hydrogen was always jumping around so that you could never be sure which was H2O and which was the ions.

Jon

 

[romex jockey]

'Ground state' is the energy level of an atom, molecule, or larger assemblage when it is at lowest energy; in this case talking about electrons in orbitals.

Think about ordinary hydrogen. 1 electron, 1 proton. Apply enough energy and you can rip that electron completely away from the proton. The amount of energy needed to rip that electron away depends on how much energy it had to start with. But there is a lowest energy orbital that the electron can be in, called the ground state.

As more protons and electrons are added to an atom, the different possible orbitals get filled up in order of lowest energy to highest. In general the electron in the highest energy state is the one available to move around. (Glossing over lots of details that I don't fully understand. You too can be a quantum mechanic!)

In a dense material like a solid (as opposed to a gas) the orbitals of the individual atoms blend together, and you should really think in terms of electron energy bands.

In a metal, the 'highest occupied energy band' is only partially filled. This means that only a smidge of energy is needed for an electron to move into a free state and move around.

In an insulator, the 'highest occupied energy band' is completely filled. For an electron to move around a large amount of energy needs to be added to rip it from the occupied band into an energy band where it can move around. Apply enough energy (say in the form of an intense electric field, or bombard things with high energy particles) and yes, you will get current flow. I don't know if porcelain will ever 'look like copper', because the energy needed for getting electrons to flow might be so much that you've vaporized the material and now have current flowing through an arc, but apply enough energy and you will have conduction.

In a semiconductor the 'highest occupied energy band' is completely filled, but an un-occupied band is available that isn't much higher in energy. This means that things like the random thermal energy of the electrons in the material is enough for some of them to be in an unoccupied band where they can move.

-Jon
In a metal 'open' electron states are available right next to occupied electrons states, so the electrons are really really free to move.

In a semiconductor, there are well defined energy ba

I'm a tad weak on quantum physics, but then most garden variety sparks such as i are rarely exposed to it Jon

such a shame too , we'd really have a handle on the rationale of our trade ....

~RJ~