Semi-dumb Question - Kayak Fishing Adventures on Big Water’s Edge

dmrides · 10-03-2010, 06:50 AM

This might be a really dumb answer, since I have no real understanding of how far electricity travels in salt water. But it would seem to me that if you were at risk of getting electrocuted, other than actually being struck by the bolt of course, so would the fish and there would be dead floating fish all over the place after every thunderstorm. Either way, I would get the F out of dodge if there was lightning on the water.

RedSledTeam · 10-03-2010, 07:01 AM

Don MacGorman, a physicist at the National Severe Storms Laboratory in Norman, Oklahoma. Had this to say on the subject

"Basically lightning stays more on the surface of the water rather than penetrating it. That's because water is a reasonably good conductor, and a good conductor keeps most of the current on the surface.
So, when lightning hits the water, the current zips across the surface in all directions. And if you're swimming anywhere in the vicinity, it'll probably hit you. But below the surface, most of the electricity is instantly neutralized. So the fish are generally spared.
Of course, if the fish happen to be surfacing, they're at risk just like you are. "
Dr. MacGorman adds that some electricity does penetrate the water, right at the strike point.

Read more: When lightning strikes the ocean why don't all the fish die? | Answerbag http://www.answerbag.com/q_view/379932#ixzz11JAk361t

RedSledTeam · 10-03-2010, 07:20 AM

Enclosed is a link to answer your questions on lightning...Check ou the bottom line.....

http://wiki.answers.com/Q/If_lightni...you_to_feel_it

If you can hear thunder, the lightning strike has already occurred since thunder is only a sonic boom caused by lightning. In order for you to feel an electric shock an electric current must pass through your body. For a current to pass through your body, your body must complete the circuit from an electrostatically charged cloud to earth/ground (in this example the ocean is the electrical earth/ground). Salt water is a great conductor of electricity/lightning and thus would immediately discharge the lightning strike. Unless the strike actually hits you, you are not in the circuit and would therefore feel nothing from a strike into the ocean - no matter how close. Consider the case of a bird perched on a high voltage supply line (maybe 440,000 volts). The bird is charged with 440,000 volts of electricity alright, but there is no circuit to ground/earth/ocean, thus the bird is not electrocuted and feels nothing.

The sea is not like your bath tub, as the sea is much much larger than even a very big bath tub. After all, there is lightning hitting some part of the oceans some place, some where, every minute of every day, isn't there? If it were just like dropping a radio into a bath tub, then people playing in the ocean at Virginia Beach would be shocked to death whenever lightning struck the water off the coast of South Africa. But we know that doesn't happen. Water has resistance. Salt water has a lower resistance than drinking water, but it does have some resistance. That resistance is cumulative per unit of volume of water. As the distance grows from the strike point to the observer, the amount of energy observable is less.

Resistance is not the major determination whether the one feels it, it is dependant on the voltage and current in that strike (changed by how far electricity has to travel, humidity, size of clouds, etc.). To see why, look at how lightning works: friction, among other things, releases negative electrons in the sky. In a storm this charge of electrons that have no place to go become attracted to the positive charged earth and take that leap. They hit the water and spread. Everything that has room takes an electron (ionizes) and the charge dissipates. My speculation is that after 100 feet or so you probably wouldn't feel it too much. Is someone going to jump in the water during a storm? It isn't recommended.

Salt water is a much better conductor than fresh. Salt water contains positive and negative ions (Na+ and Cl-), which lower its resistance. Fresh water, which contains fewer ions to transport charge, will have a higher resistance. Thinking about it a little longer: V=IR, where V = voltage, I = current, and R = resistance. In the case of a lightning bolt, I would imagine you could consider it a two resistor system, the water between you and the strike being the first resistor, and you being the second. Voltage will be supplied by the lightning bolt. The voltage will drop after traveling through the water. If there is enough voltage to provide a large enough current through yourself then you will feel it.

What a person will feel (1ma), will kill them (10ma) is not directly based on distance from the strike, it is based on the voltage gradient (across the person), which is determined by the distance from the strike and the other paths that the charge can take to Earth. So, it is not linear or easily calculated because of the many different variables.

First, pure water is an insulator. Salt and impurities make it conduct. Second, you cannot separate voltage, current and resistance. They are related to each other. The voltage of the lightning strike, along with the resistance of the water determines the current allowed to flow. Current is limited by resistance. Current can be increased by increasing voltage or decreasing resistance. Therefore, the distance from the strike will increase resistance and therefore decrease current; voltage will drop as well (as in a voltage divider circuit). There are several laws that I can think of, (multiples of resistance, etc) that would probably help answer the question, but it's just not that simple. It's not even known why lightning "chooses" the path it takes in the first place. Bottom line, if you can see lightning, get out of the water

RedSledTeam · 10-03-2010, 07:24 AM

Sorry about the big empty space on this post. My computer freaked out for a second...(must have been a lightning strike!)

LakersFan · 10-03-2010, 08:09 AM

Thanks for the excellent answers and explanation, RedSledTeam. Your empty space is forgiven!

10-03-2010, 07:20 AM	#3
RedSledTeam Daddeo Join Date: Jul 2010 Location: OC Posts: 660	Enclosed is a link to answer your questions on lightning...Check ou the bottom line..... http://wiki.answers.com/Q/If_lightni...you_to_feel_it If you can hear thunder, the lightning strike has already occurred since thunder is only a sonic boom caused by lightning. In order for you to feel an electric shock an electric current must pass through your body. For a current to pass through your body, your body must complete the circuit from an electrostatically charged cloud to earth/ground (in this example the ocean is the electrical earth/ground). Salt water is a great conductor of electricity/lightning and thus would immediately discharge the lightning strike. Unless the strike actually hits you, you are not in the circuit and would therefore feel nothing from a strike into the ocean - no matter how close. Consider the case of a bird perched on a high voltage supply line (maybe 440,000 volts). The bird is charged with 440,000 volts of electricity alright, but there is no circuit to ground/earth/ocean, thus the bird is not electrocuted and feels nothing. The sea is not like your bath tub, as the sea is much much larger than even a very big bath tub. After all, there is lightning hitting some part of the oceans some place, some where, every minute of every day, isn't there? If it were just like dropping a radio into a bath tub, then people playing in the ocean at Virginia Beach would be shocked to death whenever lightning struck the water off the coast of South Africa. But we know that doesn't happen. Water has resistance. Salt water has a lower resistance than drinking water, but it does have some resistance. That resistance is cumulative per unit of volume of water. As the distance grows from the strike point to the observer, the amount of energy observable is less. Resistance is not the major determination whether the one feels it, it is dependant on the voltage and current in that strike (changed by how far electricity has to travel, humidity, size of clouds, etc.). To see why, look at how lightning works: friction, among other things, releases negative electrons in the sky. In a storm this charge of electrons that have no place to go become attracted to the positive charged earth and take that leap. They hit the water and spread. Everything that has room takes an electron (ionizes) and the charge dissipates. My speculation is that after 100 feet or so you probably wouldn't feel it too much. Is someone going to jump in the water during a storm? It isn't recommended. Salt water is a much better conductor than fresh. Salt water contains positive and negative ions (Na+ and Cl-), which lower its resistance. Fresh water, which contains fewer ions to transport charge, will have a higher resistance. Thinking about it a little longer: V=IR, where V = voltage, I = current, and R = resistance. In the case of a lightning bolt, I would imagine you could consider it a two resistor system, the water between you and the strike being the first resistor, and you being the second. Voltage will be supplied by the lightning bolt. The voltage will drop after traveling through the water. If there is enough voltage to provide a large enough current through yourself then you will feel it. What a person will feel (1ma), will kill them (10ma) is not directly based on distance from the strike, it is based on the voltage gradient (across the person), which is determined by the distance from the strike and the other paths that the charge can take to Earth. So, it is not linear or easily calculated because of the many different variables. First, pure water is an insulator. Salt and impurities make it conduct. Second, you cannot separate voltage, current and resistance. They are related to each other. The voltage of the lightning strike, along with the resistance of the water determines the current allowed to flow. Current is limited by resistance. Current can be increased by increasing voltage or decreasing resistance. Therefore, the distance from the strike will increase resistance and therefore decrease current; voltage will drop as well (as in a voltage divider circuit). There are several laws that I can think of, (multiples of resistance, etc) that would probably help answer the question, but it's just not that simple. It's not even known why lightning "chooses" the path it takes in the first place. Bottom line, if you can see lightning, get out of the water

10-03-2010, 06:50 AM	#1
dmrides Senior Member Join Date: Aug 2009 Location: Point Loma Posts: 584	This might be a really dumb answer, since I have no real understanding of how far electricity travels in salt water. But it would seem to me that if you were at risk of getting electrocuted, other than actually being struck by the bolt of course, so would the fish and there would be dead floating fish all over the place after every thunderstorm. Either way, I would get the F out of dodge if there was lightning on the water.

10-03-2010, 07:01 AM	#2
RedSledTeam Daddeo Join Date: Jul 2010 Location: OC Posts: 660	Don MacGorman, a physicist at the National Severe Storms Laboratory in Norman, Oklahoma. Had this to say on the subject "Basically lightning stays more on the surface of the water rather than penetrating it. That's because water is a reasonably good conductor, and a good conductor keeps most of the current on the surface. So, when lightning hits the water, the current zips across the surface in all directions. And if you're swimming anywhere in the vicinity, it'll probably hit you. But below the surface, most of the electricity is instantly neutralized. So the fish are generally spared. Of course, if the fish happen to be surfacing, they're at risk just like you are. " Dr. MacGorman adds that some electricity does penetrate the water, right at the strike point. Read more: When lightning strikes the ocean why don't all the fish die? \| Answerbag http://www.answerbag.com/q_view/379932#ixzz11JAk361t

10-03-2010, 07:24 AM	#4
RedSledTeam Daddeo Join Date: Jul 2010 Location: OC Posts: 660	Sorry about the big empty space on this post. My computer freaked out for a second...(must have been a lightning strike!)

10-03-2010, 08:09 AM	#5
LakersFan Member Join Date: Mar 2009 Location: Socal Posts: 92	Thanks for the excellent answers and explanation, RedSledTeam. Your empty space is forgiven!