Hello all,

A friend of mine recently posted on Facebook looking for answers to a physics question she had thought up (best way I can put it). She was wondering if water conducts electricity, how far would the electricity from lightning striking the earth travel if it struck either a body of water or say very marshy/soggy ground? Could it be possible to be electricuted by the electricity produced by lightning that hit the ground away from yourself?

Regards

AJ

Absolutely. In fact it is highly advisable to keep your feet close together when you're outside during a thunderstorm so that you don't become a conductor from one foot to another.

I can't tell you at which minimum distance lightning has to strike in ordner not to be dangerous for you though.

Quoting Rara (Reply 1): Absolutely. In fact it is highly advisable to keep your feet close together when you're outside during a thunderstorm so that you don't become a conductor from one foot to another. I can't tell you at which minimum distance lightning has to strike in ordner not to be dangerous for you though.

It depends on several factors, including the strength of the lightning, the amount of water in the soil, and the composition of the soil itself. In soils containing large amounts of silica or quartz, you can sometimes find fulgurites (hollow natural glass tubes formed by lightning dissipating through the ground- http://en.wikipedia.org/wiki/Fulgurite ) where lightning has struck.

Quoting EGPH (Thread starter): She was wondering if water conducts electricity

Not to be pedantic or anything, but it doesn't.

Thank you all for your answers

I forgot where I saw it but you could be under the water in either a large pool or lake or the ocean and you would be essentially unharmed. The electrical charge is dispersed across the surface of the water and not "into" the water.

Tugg

Quoting FaddyPainter (Reply 3): Not to be pedantic or anything, but it doesn't.

How certain are you of that ? Rather than asking you to "take my word" that water IS indeed a conductor, try this "test";

put maybe 25cm of water in your bath tub; then, after removing your clothing, sit down in the water; then, have an "assistant" plug an electric hair dryer into a convenient AC outlet, and then toss the "plugged in" hairdryer into the water;

BTW......before conducting this "experiment", please ascertain that your life insurance is in fact paid up, and have the "assistant" post on this forum that you were "incorrect" !


[quote=EGPH,reply=0]Could it be possible to be electricuted by the electricity produced by lightning that hit the ground away from yourself?

The answer to your question is........."it all depends"...........on a whole bunch of "factors"; yes, water IS a "conductor", but it's ordinarily a fairly poor conductor; add just a bit of salt (sodium chloride), and it becomes a much better conductor. Another factor that you haven't thought of, is this; electricity "exists"in MANY different "forms"; even lightning differs greatly from one "bolt" (or discharge) to another; a "bolt" of lightning is a VERY powerful build-up of "static charge" in the atmosphere, and when it builds to a certain level, it "seeks" to "ground"; ( the reason most lightning bolts travel from "high up" to the earth, rather than in the other direction.

Another of the MANY factors involved in whether one will be "electrocuted" or not is, what are you physically in contact with ? If for example, you are standing in knee deep salt water, and a bolt of lightning strikes an object sticking out of the water near you...........it is highly unlikely that you will live to tell about it. But if you were a certain distance away from where the bolt struck the ground........and you had heavy shoes or boots on, it's quite possibly that you "may" live to tell about it; It's very hard to compare lightning with the "electricity" that we are all familiar with, such as that we buy from the electric company to run our homes with; lightning is millions of times higher in voltage and amperage that what we're accustomed to, and it behaves differently because of this. It is really not a "certainty" what a bolt of lightning striking an object may, or may not do, as they are really unpredictable, because they are all "different".

I can tell you this from my own observation, and one VERY frightening personal experience, just a few years ago;
if you are outside when a storm cell is moving in your direction, get INSIDE very quickly; "inside" can be a house, (preferably in the basement), or even a car with a metal roof; (and avoid any contact with the metal parts of the car)
NEVER seek shelter from a storm under or near trees, especially tall trees; as important as that is, paradoxically, many people are struck by lightning each year on golf courses, while standing in open space, far from building or trees. Lightning bolts definitely show a marked preference for striking metallic objects (such as metal towers and flag poles on tall buildings); many tall buildings are struck by lightning bolts many times each year.

Many people who have been in cars that were struck by a lightning bolt have survived un-harmed, (but usually very "shaken up"!)

A few years ago, I had been mowing grass with my tractor and there was a very fast moving storm heading directly towards my property; I immediately drove the tractor to a small shed that I kept it in, jumped off, and started walking briskly towards my house, which was about 250 feet away; between the shed and the house are many tall trees.....a woods; when I was almost through the trees, almost to the open back yard, a bolt of lightning struck ! VERY, VERY close to me; several things; the noise was possibly the loudest single noise I've ever heard; I can't even describe how loud it was; second........I SAW.......a HUGE blue flash; it had no direction....it was like "all around me"; your brain works very quickly also; whether or not it's as quick as lightning, I'm not at all sure; but for about one millisecond......I thought, "this is it"; I have just been struck by lightning, and now I'm dead ! But in another tenth of a second I realized......that the fact that I had ANY "awareness" proved that in fact, I wasn't dead, and that everything "still worked"; I "get scared" just like everyone else; but for some reason, I normally don't STAY "scared" very long; in this case, I only stayed scared for about a second or so; when I realized I was in fact OK. I continued on and went into the house; the whole storm cell passed by in just a couple of more minutes.

Now........to answer you MAIN question.........how far can one be standing to a lightning strike, and NOT be electrocuted;

the very minute it was apparent that the storm had passed by, I ran back out in the big trees, looking all over trying to determine which one had been struck; the amazing thing is........there was absolutely NO evidence of ANY tree that had been struck ! My neighbor's house is maybe 300 yards from my house ; ( maybe 275 meters for anyone using the "sensible system"); when I asked my neighbor if they heard the lightning strike, he said, "are you kidding ?" it sounded liked it was 5 feet away ! (he didn't see any blue flashes and sparks like I did though.) plus, he was inside the house.'

So it's really quite impossible to tell with any certainty, just how far away from a lightning bolt can one still survive, be cause there are no two lightning bolts that are equal; I can guarantee you though, that was the biggest, and by far the loudest one I have been close to, and I'm hoping I never see another one any ways near as close.

Lightning is just soooo unpredictable; every year, a few people are actually struck by lightning, and survive; many, many more are not so fortunate. If you were say, in a lake swimming, and a bolt of lightning struck a boat in the lake, maybe 100 yards away, I doubt very much that you would be electrocuted; but it would just depend on so many variables, that I would highly recommend you take every precaution to avoid having it happen !

Charley

Quoting Geezer (Reply 6): How certain are you of that ? Rather than asking you to "take my word" that water IS indeed a conductor, try this "test";

In fact water isn't a conductor. Pure water will not conduct electricity. Water appears to be a conductor because there usually are electrolytes dissolved in it.

Quoting Rara (Reply 7): In fact water isn't a conductor. Pure water will not conduct electricity. Water appears to be a conductor because there usually are electrolytes dissolved in it.

You may be right; but I have see many fatalities from people in bath tubs being electrocuted when a radio, a lamp, a hair dryer, any appliance hooked to an AC outlet, fell into the water. On the other hand..........I have never heard of anyone NOT being electrocuted when an AC device fell into the water with them.

Then there are all of the people who get electrocuted when using electrical power tools while standing on wet soil, wet grass, plus the many folks that have been electrocuted from ungrounded washing machines, while standing on a wet (or even damp) concrete floor. Add all of that up, and I feel it's pretty safe to say, if you ever come in contact with 120 AC, you better hope like hell the appliance is well grounded, and that you're NOT standing barefoot on a wet floor.

And answer me this............how do you suggest that the "average person" with no knowledge of electricity, differentiate between "pure" water, and water which has "electrolytes" dissolved in it ? (sounds like a task for a competent lab to me)

BTW.......You will notice that I DID mention sodium chloride changing things dramatically.........

Charley

Quoting Geezer (Reply 8): You may be right; but I have see many fatalities from people in bath tubs being electrocuted when a radio, a lamp, a hair dryer, any appliance hooked to an AC outlet, fell into the water. On the other hand..........I have never heard of anyone NOT being electrocuted when an AC device fell into the water with them.

People don't take baths in pure water.

Quoting Geezer (Reply 8): And answer me this............how do you suggest that the "average person" with no knowledge of electricity, differentiate between "pure" water, and water which has "electrolytes" dissolved in it ? (sounds like a task for a competent lab to me)

From a safety perspective, it's worth keeping in mind that water conducts electricity.

From a scientific perspective, it's worth keeping in mind that water doesn't conduct electricity.

Quoting vikkyvik (Reply 9): From a safety perspective, it's worth keeping in mind that water conducts electricity. From a scientific perspective, it's worth keeping in mind that water doesn't conduct electricity.

From a realistic perspective, it's worth keeping in mind that anytime you're in a bathtub with water in it, you'd better make sure there's NO electrical "gadgets" nearby, that could POSSIBLY fall into the water;

BTW.......do you suppose that could POSSIBLY be the reasoning behind the National Electric Code rule which states; "There are to be NO electrical outlets in a kitchen or bathroom, closer that six feet from a sink, basin, or bath tub." ?

I may be a retired truck driver, and you may be a highly educated engineer, but after owning (and rehabbing) several dozen rental properties over the years, plus completely rewiring several old houses, and wiring more than a few new houses, all of which have passed electrical inspection on the first inspection, please be advised, I am somewhat knowledgeable about the National Electrical code, and it's many "variants" in the Ohio counties of Butler, Hamilton, and Warren, and I even have a basic understanding of why most of these rules in the code exist.

Charley

"It's a tasty desert topping."
"No, it's a space-age floor polish."
STOP! You're both right!

Pure water will not conduct electricity. Impurities, particularly salts, when dissolved in water will separate into negatively (Ci) and positively (Na) charged ions (read atoms) facilitating conductivity.

I like vikkyvic (Rep 9) answer the best. Either way, I ain't gonna try the James Bond bathtub trick. "Shocking. Positively shocking." (I think that was in "Dr. No"). regards...jack

Quoting Geezer (Reply 10): From a realistic perspective, it's worth keeping in mind that anytime you're in a bathtub with water in it, you'd better make sure there's NO electrical "gadgets" nearby, that could POSSIBLY fall into the water; BTW.......do you suppose that could POSSIBLY be the reasoning behind the National Electric Code rule which states; "There are to be NO electrical outlets in a kitchen or bathroom, closer that six feet from a sink, basin, or bath tub." ? I may be a retired truck driver, and you may be a highly educated engineer, but after owning (and rehabbing) several dozen rental properties over the years, plus completely rewiring several old houses, and wiring more than a few new houses, all of which have passed electrical inspection on the first inspection, please be advised, I am somewhat knowledgeable about the National Electrical code, and it's many "variants" in the Ohio counties of Butler, Hamilton, and Warren, and I even have a basic understanding of why most of these rules in the code exist.

I didn't deny any of that. In fact, I supported most of that. Dunno if you skipped 2/3 of my post, but here it is again:

Quoting vikkyvik (Reply 9): People don't take baths in pure water

Quoting vikkyvik (Reply 9): From a safety perspective, it's worth keeping in mind that water conducts electricity.

Quoting EGPH (Thread starter): Could it be possible to be electricuted by the electricity produced by lightning that hit the ground away from yourself?

Ahhhem.........May I remind everyone that the OP's question is.........."If the lightning struck "over there", and I was standing "over here", would I get electrocuted ?

Again, I would have to answer, "it all depends"; How far is "over here" from "over there" ? Is the ground wet ? If it IS wet, is the water "pure".....( as in distilled water ); or does it have a wee bit of "contamination" in it ? Are you barefoot ?
Do you have an umbrella ? Are you standing up, sitting down, or lying on your back ?

There are just soooooo many variables.........overall, I'm inclined to think that if the lightning struck the ground, say, 50 feet from where you are, you may very well live to tell about it; (but I can't guarantee it) (and even if you do survive, you may very well find that your nerves are completely "frazzled".

Charley

Quoting Geezer (Reply 10): I may be a retired truck driver, and you may be a highly educated engineer, but after owning (and rehabbing) several dozen rental properties over the years, plus completely rewiring several old houses, and wiring more than a few new houses, all of which have passed electrical inspection on the first inspection, please be advised, I am somewhat knowledgeable about the National Electrical code, and it's many "variants" in the Ohio counties of Butler, Hamilton, and Warren

Well you just went from being a retired truck driver who thought water conducts electricity to being a retired truckdriver who knows it does in fact not.   In other words. you learned something new - isn't that what we all come to this forum for?

Quoting Geezer (Reply 6): Many people who have been in cars that were struck by a lightning bolt have survived un-harmed, (but usually very "shaken up"!)

Happened to me. Just outside downtown Houston. Lots of smoke, noise and burnt wiring smell, but the car and I were fine. I don´t really think you have time to be scared. It´s really pretty quick.

Quoting Geezer (Reply 13): Ahhhem.........May I remind everyone that the OP's question is.........."If the lightning struck "over there", and I was standing "over here", would I get electrocuted ?

I don´t think there´s an answer to this question. What really makes me paranoid is what they call "blue lightning" which is the bolt discharged from a cell tens of kms away, where you may not even be aware it exists. People have been killed in clear, blue, sunny skies.

Quoting EGPH (Thread starter): how far would the electricity from lightning striking the earth travel if it struck either a body of water or say very marshy/soggy ground

Actually - while distance from the strike point IS a factor, you might be fine depending on how far apart youe feet are.ie. if u are standing or taking a step.

Voltage does not kill. Current does. Current only happens where there is voltage (potencial) difference. The farther ur legs are the bigger the potencial diffrence - and the bigger the current

It is possibe that by having ur feet togther you surive a strike.

And. Actually wet ground having a lower resistance would create less potencial differnce between your feet. So wet ground would actually help you survive.

I've done 20ft before... it was a small one luckily.
It hit wet ground, and I was on dry ground...
Both were paved surfaces but of different materials.

While I survived, my ears rang in my head for a good day or two...

I'll tell you how I happened to get a little "first hand" knowledge about all of this "wet ground", "dry ground" business.....(the HARD way)

I was painting my single story brick house I lived in for 50 + years; (the lap-siding on the gable end) I was standing on my aluminum walk board, which was supported on either end by my aluminum ladder jacks, which were attached to two 16 ft aluminum ladders. It was in the summer time, and a bright, sunshiny day.

I got to the corner that was next to the road, which is where the service drop cable from the transformer on the pole on the side street enters the weather head on the service entrance mast, comes down through the six foot mast, and is "attached" to the three big conductors of the service entrance cable, (which then goes through the wall into the garage, and into the 200 amp service panel box.

Now.........when these two sets of conductors are attached to one another by the power company, the way they do it is this; each individual conductor is a #2-0; they are roughly 13, maybe 14mm in diameter; each conductor is inserted into a bronze coupling called an "acorn clamp"; the acorn clamp has a 13mm bronze bolt in it, and when the conductors are inserted into the clamp from either direction, this big heavy bronze bolt is tightened up against the two copper conductors, squeezing them together, and holding them together very firmly. When the power company lineman gets all three connections made, he then proceeds to start taping them up with electrical tape, to insulate them.

Now.......when I was about to start painting around and under where the service drop was attached to the service entrance cable, I was quite confidant that all three of these connections are well taped, and were therefore nothing for me to worry about; after all, I use "electrical tape" all the time; in my spare time, I'm always doing wiring on houses that I buy to rent and to sell, so I'm very familiar with vinyl electrical tape, and it's insulating ability.

What I didn't take into account though was........this house was built around 1955 or thereabouts, which was about 5 years BEFORE vinyl electrical tape was even invented. "Back then", electrical tape was referred to as "friction tape", and it was made from fabric impregnated with some sort of tarry "stuff". It was just fine when it was first applied, and it was still "OK" for probably 10 or 15 years; but after 20 or 25 years of rain, sun, hot, cold weather, it no longer afforded ANY insulation at all; matter of fact, the heads of all three acorn clamp bolts were completely BARE ! (I know, I shoulda looked closer) (but I didn't)

I first became "aware" of this failure of this obsolete tape, when my bare, sweaty shoulder came into contact with one of the bolts. At which point I was firmly in contact with one "leg" of a 200 amp service, and I was having a huge problem getting untangled from the three big conductors, all while standing on aluminum which was on bare ground; each of those two "hot" conductors is 120 volts; I was standing on "ground"; I can't really say just how long it took me to get free from the bare connection, but it seemed like about half an hour ! (Don't laugh.....at the time, it wasn't the least bit humorous) when I finally did get loose, all I could do was lay down on the walk board; it's impossible to describe, but I felt like a wet rag. After maybe 10 minutes, I managed to climb down the ladder, and laid down in the grass for maybe another 10 or 15 minutes; I felt like about half way between "just fell out of an airplane", and "just hit by a train".
I couldn't get up and walk after 20 or so minutes, so I crawled into the house, and got to the phone; But I didn't know who to call, and I didn't feel "up" to looking up phone numbers; then I remembered ....we had like 3 or 4 emergency numbers, just by pushing a few buttons. (one of those antique push button phones from yesteryear); when I pushed one, second ring, my son answered ! "Hello"? "is that you Chris"? "yes"; "I think I just got electrocuted"! "well why are you calling me ? I'm in California ! Call a damned ambulance ! No..wait....I'll call the ambulance....don't go away"! Me; "don't worry".

So my son in California (who at the time only had a BS in EE, but now has a PhD) calls an ambulance in Cincinnati, which came and transported me to a hospital; as it turned out, the doctors at the ER weren't all that familiar with my immediate situation, so they called some one else.....( possibly in California ? ) who knows. Anyway, they were able to determine that I was still alive, and the next day two engineers from Cincinnati Gas and Electric came to see me. I learned quite a bit about the subject of humans coming into contact with power lines. The guys from C.G.&E. took me out to where my ladders were still sitting; one guy takes a screw driver and digs around in the dirt beneath the ladder; he said: "see that loose dirt"? ME; yep HE: it's DRY as a bone ! "which BTW, is the ONLY reason you are still here, instead of downtown in the morgue." You were definitely grounded, but just not perfectly grounded; had the soil been wet........different outcome altogether!

So back then I was "ignorant", bordering on "stupid"; since then, I'm "careful"......very, very careful ! (And I didn't even try to sue the manufacturer of the obsolete fabric tape that degraded to nothing in the weather over 20 years ). (and believe it or not, those guys from C.G, & E. didn't say anything about whether wet ground has "pure water" in it or just plain old "wet" water ! Oh.....a day or so later C.G.& E. sent a truck out and the guy put a whole roll of vinyl tape on each acorn clamp, then wrapped the whole thing with a rubber blanket, and taped it in place ! And that's the last time I've ever been "shocked" ! (because I'm a lot more careful now !)

The "thrust" of this story is...........several; if you EVER have to paint (or do ANYTHING around your service drop conductors, call the power company FIRST, and they will stop by, and wrap a rubber blanket around the connections.
Second; anytime you're doing anything on a ladder near a power line, FORGET that aluminum ladder altogether; go buy a fiberglass ladder; little heavier, little more money, but you can't spend your money anyway if you get electrocuted, messing around on an aluminum ladder.

One other thing needs to be mentioned here; there are many, many people who will tell you that the 120 volts of AC current in you house wiring is "insufficient" to electrocute a person; they "assume" this because they have been "shocked" many times, with no ill effect. The reason they survived is because they were insufficiently grounded when they touched the hot wire. Any qualified electrician, or any electrical engineer will tell you, it only takes a few mili-amps to be lethal when you are well grounded, whether you're in a bath tub full of water, or standing on a damp concrete basement floor; every lighting circuit in your house is at least 15 amps, some are 20 amps. But don't take my word for it; call your power company; believe me, they know what they're talking about.

Charley

Quoting Geezer (Reply 18): The "thrust" of this story is...........several; if you EVER have to paint

A lot of people get killed here every year through electrocution from doing stuff up in the roofs. They just don´t know better and are ill-equipped and ill-trained.

Quoting Rara (Reply 7): In fact water isn't a conductor. Pure water will not conduct electricity. Water appears to be a conductor because there usually are electrolytes dissolved in it.

Quoting cptkrell (Reply 11): Pure water will not conduct electricity. Impurities, particularly salts, when dissolved in water will separate into negatively (Ci) and positively (Na) charged ions (read atoms) facilitating conductivity.

I'll give both of you a trillion dollar coin if you give me 1 ml of pure liquid water with no conductivity at all. If you're going to be pedantic, do it right.   

[Edited 2013-01-21 04:43:01]

You can take a trip to Mt Evans, Colorado and take a road trip up to the summit.
14,240 ft, the highest automobile road in North America.

It has a very large sign in the parking lot up top.

Do not leave your vehicle during storms
HUMANS MAKE EXCELLENT LIGHTNING RODS

Okie

Quoting EGPH (Thread starter): A friend of mine recently posted on Facebook looking for answers to a physics question she had thought up (best way I can put it). She was wondering if water conducts electricity, how far would the electricity from lightning striking the earth travel if it struck either a body of water or say very marshy/soggy ground? Could it be possible to be electricuted by the electricity produced by lightning that hit the ground away from yourself?

This answer is very difficult due to a lot of the postitions already put forward.

Water by itself in Ulta Pure H20 form is a very poor conductor. However minerals, salts and other items dissolved in Water can make it a much readier conductor. So the real question your fiend should be asking, is what is in the water, and what is in the very marshy ground? I would assert a close to worst case scenerio that your friend is tetherered to the strikepoint by a copper wire. In that case they are in deep trouble.
In all other cases from their it depends on the density and distance of the conducting materials between the person and the strike.
Rubber boots or Glass Slippers would make your friend a lot safer .

Quoting vikkyvik (Reply 9): People don't take baths in pure water.

What everyone forgets, is that usually when people take baths, they take warm baths, and this opens up the pores on people. Especially the sweat glands, which contain lots of salts and electrolytes.

Quoting mt99 (Reply 16): And. Actually wet ground having a lower resistance would create less potencial differnce between your feet. So wet ground would actually help you survive.

I would really love to hear you attempt to "explain" that to the two guys from Cincinnati Gas & Electric !

Charley

Quoting aloges (Reply 20): I'll give both of you a trillion dollar coin if you give me 1 ml of pure liquid water with no conductivity at all. If you're going to be pedantic, do it right.

I'll give you the trillion dollar back if you give me ANY substance with "no conductivity at all".

What's wrong with getting stuff right? In the old days people thought malaria was caused by bad air (hence the name) in the vicinity of swamps. By consequence that wasn't so wrong, only that not the air itself was the vector, but rather the mosquitoes within it. Likewise it may be enough for a technician to know that "water conducts electricity" but it's still interesting that it's the electrolytes within the water and not the water itself.

Quoting Rara (Reply 24): Likewise it may be enough for a technician to know that "water conducts electricity" but it's still interesting that it's the electrolytes within the water and not the water itself.

I was referring to the self-ionization of water (H₂O + H₂O ⇌ H₃O⁺ + OH^-), which tends to be disregarded when people refer to chemically pure water. The belief seems to be that it consists of nothing but H₂O, which is incorrect.

Quoting Geezer (Reply 23): I would really love to hear you attempt to "explain" that to the two guys from Cincinnati Gas & Electric !

Well - we are not talking about the same thing. the OP was about a lighting strike - you about touching a wire. What you described is completely different..

When it comes to the original question - i stand by my assertion that a wet soil will increase you likely hood to survive a nearby lightning strike.

Quoting aloges (Reply 25): I was referring to the self-ionization of water (H2O + H2O ⇌ H3O+ + OH-), which tends to be disregarded when people refer to chemically pure water. The belief seems to be that it consists of nothing but H2O, which is incorrect.

Ah ok, sorry. That's true. Still this conductivity is on the nano scale, isn't it? I remember that in school we tried to close an electric circuit with regular drinking water and with aquadest, and the latter appeared to be non-conductive.

Quoting aloges (Reply 20): I'll give both of you a trillion dollar coin if you give me 1 ml of pure liquid water with no conductivity at all.

What's your border value for "no conductivity at all"? To give a number, ultra pure water from our purifier has routinely a specific resistance of 18.2 MOhm cm, which is pretty close to "no conductance". In other words: if you use a column of water, 5 mm squared in cross section and one cm high, attach one end to your finger and the other one to a 380 kV high voltage transmission line, you will have a current of 5 mA flowing to your skin. Anything below 20 mA won't endanger you. So it's pretty accurate to say that water isn't a conductor for all that is useful in the real world...

Quoting AustrianZRH (Reply 28): To give a number, ultra pure water from our purifier has routinely a specific resistance of 18.2 MOhm cm,

Wouldn't it be rather 18.3 MOhm/cm? 18.2 means that your cartridges are (very) slowly starting to deteriorate.

BTW, 18.3 MOhm/cm is the maximum specific resistance of water due to

Quoting aloges (Reply 25): self-ionization of water (H2O + H2O ⇌ H3O+ + OH-),

Quoting WildcatYXU (Reply 29): Wouldn't it be rather 18.3 MOhm/cm?

A common misunderstanding  . No, it is indeed MOhm*cm, as the resistance is directly proportional to the length and inversely proportional to the cross section of your conductor:

R = r*l/A.

As [R] = Ohm, [l] = m, and [A] = m^2, you get for the specific resistance:

[r] = [R]*[A]/[l] = Ohm*m^2/m = Ohm*m.

Damn ! It's too bad we can't dig Richard Feynman up and see what he says about all of this.............

Let's see now; yeah, the "electricity" in the "wire" came from the power plant, where it was most likely "created" by a big generator...........

and the "lightning" came from.......? The "sky" ? Where it was created as "static" by a WHOLE BUNCH of really little teeny weenie "thingies".....(electrons maybe ?) But just let me ask you this; have YOU ever taken a close look at a eight foot diameter, 150 ft tall oak tree that was just "struck" by a lightning "stroke", (or "bolt"), which ever.....?

I have ! And I can just about promise you one thing; if you had been standing anywhere NEAR the base of that oak tree, in a big mud puddle, (with your feet TOUCHING each other)..........I'll BET you that the first people to come on the scene would have mistaken you for a "fried egg" !

Charley

P.S. The reason I'm so sure of this is because that oak tree looked a lot like a kitchen match standing on end that had just whacked with a sledge hammer. BTW.........I just remembered........it was pouring down rain when the lightning hit the tree.....didn't seem to make much difference though

Charley

A lightening strike -- perhaps a million volts of electrical potential -- hundreds of thousands of amps -- ionization on a massive scale -- things which normally might be good insulators (air, water) suddenly become conductors. All sorts of factors might come into play for a near miss, but for a direct hit I don't think it matters if the ground is wet, dry, if it's kitty litter, if you're standing on your head, etc. The outcome will not be good.

The OPs original question was whether one (not standing at or near ground zero) could be electrocuted by current flowing away from the strike. I'm thinking that at a sufficient distance where one is safe from the strike itself, the potential difference between any two points on the ground is probably not big enough to matter. If though, for some reason, the potential between two points was high, then sure, wet ground would probably be safer than dry ground (give the current an easier path than your body), having feet closer together would be better, etc. But, if you're close enough that the potential between two points on the ground is significant, I'm gonna guess that it won't matter how you're configured 'cuz you're already toast.

Quoting Geezer (Reply 6): How certain are you of that ? Rather than asking you to "take my word" that water IS indeed a conductor, try this "test";

Quoting Geezer (Reply 8): how do you suggest that the "average person" with no knowledge of electricity, differentiate between "pure" water, and water which has "electrolytes" dissolved in it ? (sounds like a task for a competent lab to me)

I did a science fair experiment with this. Pure water doesn't conduct electricity. To prove this, take a 6 volt battery and attach a cable to each pole long enough to be dipped into a cup of water. Get a small lightbulb (like a car light or lamp) and attach cables to it as well. With a multimeter, measure the electricity flowing through. You'll find that barely any flows. Add salt to the solution and you'll see the lightbulb light up. That's because the salts dissolve into ions which effectively permit the flow of electricity. Of course, if you were to take a bath in any kind of water (salt, pure, etc.) and put electricity you'll be shocked. Why? Your skin. Dead cells which are composed of something and which permit the flow of electricity.

Water by itself won't conduct unless there are ions.

Quoting NoWorries (Reply 32): The OPs original question was whether one (not standing at or near ground zero) could be electrocuted by current flowing away from the strike. I'm thinking that at a sufficient distance where one is safe from the strike itself, the potential difference between any two points on the ground is probably not big enough to matter. If though, for some reason, the potential between two points was high, then sure, wet ground would probably be safer than dry ground (give the current an easier path than your body), having feet closer together would be better, etc. But, if you're close enough that the potential between two points on the ground is significant,

Thank you - you probably explained more clearly than i could  

Quoting NoWorries (Reply 32): I'm gonna guess that it won't matter how you're configured 'cuz you're already toast.

Not going discount this either. Factors like foot position, distance from strike , ect are correct from a purely technical point of view - but practically it might be irrelevant.

Quoting Geezer (Reply 31): et's see now; yeah, the "electricity" in the "wire" came from the power plant, where it was most likely "created" by a big generator........... and the "lightning" came from.......? The "sky" ? Where it was created as "static" by a WHOLE BUNCH of really little teeny weenie "thingies".....(electrons maybe ?) But just let me ask you this; have YOU ever taken a close look at a eight foot diameter, 150 ft tall oak tree that was just "struck" by a lightning "stroke", (or "bolt"), which ever.....?

Not sure what you are tying to say. That electricity is electricity and that it had the same effects regraddless where and how you come in contact with it?

I give you: Tesla Cage of Death!

http://www.youtube.com/watch?v=Zi4kXgDBFhw

Quoting mt99 (Reply 34): Not sure what you are tying to say.

The stark contrast between replies 30 and 31 is quite amusing.  

Quoting einsteinboricua (Reply 33): Water by itself won't conduct unless there are ions.

As explained above, there is no liquid water that doesn't contain ions. It simply does not exist. So any liquid water is conductive, however small that conductivity may be.

Quoting mt99 (Reply 34): Not sure what you are tying to say. That electricity is electricity and that it had the same effects regraddless where and how you come in contact with it? I give you: Tesla Cage of Death!

What I'm trying to say, (and what you seem to be trying very hard to disagree with, is) ANY lightning "bolt" is extremely powerful, can (and sometimes do) consist of MILLIONS of volts of "potential", not to mention thousands of amperes of electrical current.

Now........what I'm "guessing" is...........anyone standing on both feet, one foot, on their hands, or EVEN on their head, much closer than a few hundred feet from a point where a lightning bolt is "about" to strike, PROBABLY has a very great "potential" of ending up much like that kitchen match which I alluded to in my analogy; and I'm also "guessing" that the relative "wetness" of "dryness" of the "ground" (or whatever it is that they're standing on), probably isn't going to have very much bearing on the outcome.

We have all seen pictures and films of controlled "experiments" where infinitely small amounts of "amperage" is created by a "Tesla coil" (or a Van DeGraff generator I believe it is called?), wherein HUGE colorful blue "arcs" (with thousands of volts, and minuscule amperage) leap across great distances (and so on); and yes, it IS fun to watch such demonstrations, HOWEVER, it isn't getting us any nearer to the original question, posed by the OP.

The way this thread seems to be going, I'm starting to think that I MAY end up needing to "consult" with the only person I'm reasonably well acquainted with who has a PhD in EE, (my oldest of two sons). Like almost all engineers, he almost always "knows everything"; (or at least thinks he does.)

Charley