Nestor_Kelebay
Emperor Penguin
- Joined
- Mar 28, 2009
- Messages
- 1,844
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Rebecca:
If you look closely, the radio on the table is plugged into a power bar. That power bar is kept above the water's surface by the two floating sandals (one at each end of the power bar), so that the electrical connection between the power bar and the radio doesn't actually get wet. So, that connection is insulated by air, which has a very high resistance.
The wire to the power bar is submerged. However, if there are no breaks in the insulation around the wire, then electricity cannot "leak out" of the wire into the surrounding water.
Mixing water and electricity is only dangerous because water has a lower electrical resistance than air, and so if the power bar were to sink, electricity would "leak out" into the surrounding water to energize all the water in the pool up to 110 volts AC.
I have a bit of trouble with that picture because I'm not convinced the people in that pool would be in any real danger even if the power bar were to sink. In order for electricity to harm you, it has to flow THROUGH you, thereby damaging the cells along the path it takes. If the power bar were to sink, then the entire pool of water would become energized, but as long as the men stayed in the pool, electricity would not flow through them. (Cuz where would it flow, into the air around them? No. Air is an insulator.) They'd be like a person touching a Van Der Graff generator; they'd be charged up to the same voltage as the generator, but because electricity wouldn't be flowing through them, they'd be in no danger.
The men could only get a shock if they stepped out of the pool and (with one foot still in the water) touched a ground of some sort (like a steel pole that goes into the ground). But, if you look in the background to that picture, the pool is, as best we can tell, surrounded by paving stones, which are also electrical insulators. And, even if someone stepped out of the pool and stood on a conductor that was grounded:
A) the current through their body would be very much reduced because of the high resistance of the fresh water between that person's body and the power bar. The high resistance of the fresh water in the pool is going to very much limit the current flowing through the water, and hence the body of the person stepping out of the pool, and
B) the path the electricity would travel would be in one leg and out the other. It wouldn't travel across the person's heart, and that's where the greatest danger lies. Since the heart muscle works on electrical impulses from nerves, the greatest danger is if the heart stops as a result of an electric shock, and that happens when the path of the electricity crosses the area of the heart, like in an arm and out the opposite leg, or in one arm and out the other arm.
Actually, those guys would be in more danger if any of them were to pick up the radio to change the channel or the volume. That's cuz then they'd be putting their bodies between the voltage source and any potential ground. There's an awful lot of water in a pool, and the current flowing into that water just to energize it up to 110 volts might be enough to give the person a pretty good shock, even if the charge didn't leave the pool.
So, that particular picture looks like these guys are unaware of the danger they're in, but I can't help thinking that as long as none of them picked up the radio, I really don't think they're in very much danger at all. You don't want to use a hair dryer or tune a radio while in a bath tub because then you're putting your body between the voltage source and the ground (the tub's metal drain pipe). But, that's not the case here.
If you look closely, the radio on the table is plugged into a power bar. That power bar is kept above the water's surface by the two floating sandals (one at each end of the power bar), so that the electrical connection between the power bar and the radio doesn't actually get wet. So, that connection is insulated by air, which has a very high resistance.
The wire to the power bar is submerged. However, if there are no breaks in the insulation around the wire, then electricity cannot "leak out" of the wire into the surrounding water.
Mixing water and electricity is only dangerous because water has a lower electrical resistance than air, and so if the power bar were to sink, electricity would "leak out" into the surrounding water to energize all the water in the pool up to 110 volts AC.
I have a bit of trouble with that picture because I'm not convinced the people in that pool would be in any real danger even if the power bar were to sink. In order for electricity to harm you, it has to flow THROUGH you, thereby damaging the cells along the path it takes. If the power bar were to sink, then the entire pool of water would become energized, but as long as the men stayed in the pool, electricity would not flow through them. (Cuz where would it flow, into the air around them? No. Air is an insulator.) They'd be like a person touching a Van Der Graff generator; they'd be charged up to the same voltage as the generator, but because electricity wouldn't be flowing through them, they'd be in no danger.
The men could only get a shock if they stepped out of the pool and (with one foot still in the water) touched a ground of some sort (like a steel pole that goes into the ground). But, if you look in the background to that picture, the pool is, as best we can tell, surrounded by paving stones, which are also electrical insulators. And, even if someone stepped out of the pool and stood on a conductor that was grounded:
A) the current through their body would be very much reduced because of the high resistance of the fresh water between that person's body and the power bar. The high resistance of the fresh water in the pool is going to very much limit the current flowing through the water, and hence the body of the person stepping out of the pool, and
B) the path the electricity would travel would be in one leg and out the other. It wouldn't travel across the person's heart, and that's where the greatest danger lies. Since the heart muscle works on electrical impulses from nerves, the greatest danger is if the heart stops as a result of an electric shock, and that happens when the path of the electricity crosses the area of the heart, like in an arm and out the opposite leg, or in one arm and out the other arm.
Actually, those guys would be in more danger if any of them were to pick up the radio to change the channel or the volume. That's cuz then they'd be putting their bodies between the voltage source and any potential ground. There's an awful lot of water in a pool, and the current flowing into that water just to energize it up to 110 volts might be enough to give the person a pretty good shock, even if the charge didn't leave the pool.
So, that particular picture looks like these guys are unaware of the danger they're in, but I can't help thinking that as long as none of them picked up the radio, I really don't think they're in very much danger at all. You don't want to use a hair dryer or tune a radio while in a bath tub because then you're putting your body between the voltage source and the ground (the tub's metal drain pipe). But, that's not the case here.
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