Please disprove this for me (science/electricity related.)

[Chaotic42]

Originally posted by: KK
What about a squirrel on these lower voltage lines? Do they just levitate?
KK

I've seen them get trapped halfway between two power lines. They're repelled from both by an equal force. Poor things just starve.

 

[notfred]

Why are half of these posts answers to a different question? I didn't ask "Why don't birds get electrocuted on power lines'.

 

[Chaotic42]

Originally posted by: notfred
Why are half of these posts answers to a different question? I didn't ask "Why don't birds get electrocuted on power lines'.

The magnetic field will not repel the bird in the way that first comes to mind, which is like two N-poles on two different magnets. They fly apart. That isn't what happens.

The birds are repelled because the magnetic field messes with their internal navigation. It would be like you trying to sit in a chair attached to a rapidly spinning platform. It would be almost impossible.

This is all AFAIK, I'm not a magnetoaviologist.

 

[element]

Originally posted by: Heisenberg

Originally posted by: element
I've seen extremely powerful electromegnets in research labs that could repel anything. They showed a strawberry floating in the air with it.

The electromagnet was huge though, the size of maybe a 3 story house or thereabouts.

I doubt the magnetic field around a powerline is enough to physically repel the bird, but maybe it can affect their brain like Ameesh said.

Then again it's not impossible that there is enough magnetic field around a 700+kv line to repel also, though I'm not sure.

The giant electromagnet I spoke of had a lot of windings around it, and a lot of current through it. The powerline has no windings, just the 1 line.

While it is possible to levitate normal objects (I've seen pictures of frogs) with extremely large magnetic fields, there's no way in hell a high-tension wire produces such a field. You need fields of several thousand Tesla's to do that. The magnetic field from a wire depends on the current and distance from it. The current through high tension wires is purposely small and the voltage purposely high to avoid power loss from the resistance of the wire over large distances. The field might be strong enough to mess with a bird's navigation as the Earth's field is pretty weak, but I don't know if that's true or not.

Agreed, that's why I wrote the bolded part.

I disagree with you on the earth's magnetic field being weak however. It's very strong as is evidenced by the sheer distance it covers.

Although of course in close proximity to a magnetic source it can be overcome.

 

[Calin]

Shortly: the birds have electrical capacity, so by aproaching a high voltage line (not x0 000 V, but x00 000 V is high voltage common in long transmission lines) there can be a "zap" between the bird and the line. Imagine it is somewhat similar with a plane that is hit by a lightning strike in the air. How it is hit, as it is not grounded? Well, its own electrical capacity is the answer. Imagine also if you touch someone that is loaded with static electricity, while both wear rubber shoes. There is a spark (maybe) and a shock (certainly).
Can such a shock be fatal to the birds? Hardly, as the circuit is closed thru the legs, and the heart is not in the way of the current. However, it certainly is not pleasant. By the way, the 760 kV (as gwells777 said), is capable to create a spark thru the thin air up to several inches.
About other magnetic effects - the pure magnetic field effect is neurtalised as the current that flows is alternative (every cycle, half the time the magnetic field has one orientation, the other half of the cycle has the oposite orientation). You might try to keep a magnet close to a power transformer - there is no difference between the powered transformer and unpowered transformer. Try that with a solenoid in continous current, and the result is totally different.

Calin

 

[3chordcharlie]

The magnetic field answer is right - and they ARE talking about the really high-powered lines.

The other answer is also right- birds don't get zapped unless they manage to touch two low-power lines at the same time. This is one reason why the lines are fairly far apart. If I'm not mistaken, they were moved fartherapart a few years ago so they would stop killing eagles ad the like, which often sat on the light poles, and were large enough to touch two lines at once.

 

[Atomicus]

so you guys must be telling me that if I were to jump and grab the highest power line, I won't die because I'm not grounded?

 

[Calin]

Originally posted by: Atomicus
so you guys must be telling me that if I were to jump and grab the highest power line, I won't die because I'm not grounded?

Yes, but try to grab the lines with your right hand if your heart is on the left side of the chest. You might be shocked a bit, and (but I'm not sure) you might feel (or not) continous electricity flowing if your electric capacity is big enough and your hands are wet.
however, it would be much safer to grab yourself with your feet 😀
However, for every power line you would be capable to jump to, the voltage is not high enough to be felt when you are hanging from it (not grounded), even if your hands would be sweaty

Calin

 

[Atomicus]

wow... I feel like I fool. I can't believe I believed my physics professor who has a masters and 15+ years of teaching experience. Physics > EE so I'm outta here :|

 

[3chordcharlie]

Originally posted by: Atomicus
so you guys must be telling me that if I were to jump and grab the highest power line, I won't die because I'm not grounded?

Electricity can kill you, but it isn't some sort of unpredictable 'beast'. My grandfather used to wire light fixtures and all sorts of things without bothering to turn off the power (I'm NOT recommending this). He said he could occasionally feel a bit of tingling, but not much else.

It's not what killed him.

 

[cquark]

I disagree with you on the earth's magnetic field being weak however. It's very strong as is evidenced by the sheer distance it covers.

Field strength is measured in Tesla and the Earth's magnetic field ranges from 20-70 microTesla, compared to man-made magnets millions of times stronger. Of course, you're correct that the volume of the field is very high, so the total energy contained in the magnetic field is large.

 

[Calin]

Originally posted by: notfred
Why are half of these posts answers to a different question? I didn't ask "Why don't birds get electrocuted on power lines'.

OK,. sorry. Your answer is: an alternative current won't produce a magnetic field capable to attract or repel something that doesn't have electro-magnetic properties.
As an example: a magnet is not attracted or repelled by the (electro)magnetic field of a solenoid in alternative current. A solenoid can attract or repel another solenoid, if the induced current phase in the "inducted" solenoid can be shifted (using a capacitor as the load for the second solenoid). If the second solenoid has a resistive load, the currents are in anti-phase and the resultant attraction will compensate.

So even if the birds would have magnets or iron bars attached at their feets, they would not feel magnetic effects

 

[3chordcharlie]

Originally posted by: notfred
Why are half of these posts answers to a different question? I didn't ask "Why don't birds get electrocuted on power lines'.

Because your topic is actually a red herring, just like Mind Trap wanted it to be.

It's not an electricity/magnetism question. It's a biology question.

 

[Ogg]

Originally posted by: Atomicus
Trust me, I'm an environmental engineer and I've read about it.

Yesterday you said you were an lowly intern :Q😀😱😉

 

[PottedMeat]

Originally posted by: 3chordcharlie

Originally posted by: Atomicus
so you guys must be telling me that if I were to jump and grab the highest power line, I won't die because I'm not grounded?

Electricity can kill you, but it isn't some sort of unpredictable 'beast'. My grandfather used to wire light fixtures and all sorts of things without bothering to turn off the power (I'm NOT recommending this). He said he could occasionally feel a bit of tingling, but not much else.

It's not what killed him.

yep, its the current that kills you


as long as there is no return path for the current, you would be ok.
if you were to touch two wires, depending on how much resistance your body has between the two touching points, current would flow. It's been awhile but i think it was ~10mA could stop the heart if you were to hold one conductor with one hand and the other conductor with your other hand.

There was a really cool show on the History Channel i think that showed linemen in choppers working on those ~200kV/700kV lines. Nobody gets hurt unless something bridges the conductors.

 

[3chordcharlie]

Originally posted by: PottedMeat

Originally posted by: 3chordcharlie

Originally posted by: Atomicus
so you guys must be telling me that if I were to jump and grab the highest power line, I won't die because I'm not grounded?

Electricity can kill you, but it isn't some sort of unpredictable 'beast'. My grandfather used to wire light fixtures and all sorts of things without bothering to turn off the power (I'm NOT recommending this). He said he could occasionally feel a bit of tingling, but not much else.

It's not what killed him.

yep, its the current that kills you


as long as there is no return path for the current, you would be ok.
if you were to touch two wires, depending on how much resistance your body has between the two touching points, current would flow. It's been awhile but i think it was ~10mA could stop the heart if you were to hold one conductor with one hand and the other conductor with your other hand.

There was a really cool show on the History Channel i think that showed linemen in choppers working on those ~200kV/700kV lines. Nobody gets hurt unless something bridges the conductors.

That does sound cool - I'd love to see that.

 

[spidey07]

Originally posted by: PottedMeat

Originally posted by: 3chordcharlie

Originally posted by: Atomicus
so you guys must be telling me that if I were to jump and grab the highest power line, I won't die because I'm not grounded?

Electricity can kill you, but it isn't some sort of unpredictable 'beast'. My grandfather used to wire light fixtures and all sorts of things without bothering to turn off the power (I'm NOT recommending this). He said he could occasionally feel a bit of tingling, but not much else.

It's not what killed him.

yep, its the current that kills you


as long as there is no return path for the current, you would be ok.
if you were to touch two wires, depending on how much resistance your body has between the two touching points, current would flow. It's been awhile but i think it was ~10mA could stop the heart if you were to hold one conductor with one hand and the other conductor with your other hand.

There was a really cool show on the History Channel i think that showed linemen in choppers working on those ~200kV/700kV lines. Nobody gets hurt unless something bridges the conductors.

yeah, but did you see the kinds of suits and equipment they would use to discharge the potential the chopper had? It was like some huge metal grate the guy had to walk out on. freaky stuff.

 

[So]

1. As said above, birds don't get zapped b/c they aren't grounded.
2. I'm sure I've seen birds on Transmission lines before, even huge 500kv ones
3. If there was any physical effect, it would attract the birds, not repel them (sorry Atomicus, your hovering birds azre PURE fantasy). Imgaine hundreds of birds magnetically stuck to powerlines (pretty funny, IMO :laugh: |)
3. I think we can agree that from a magnetic perspective, humans are basically the same as a big bird. An MRI machine makes a magnetic field many orderes of magnitude bigger than a powerline, so huge that it has been known to drag huge oxygen tanks across the room, but people, so long as they have no ferromagnetic materials on them, can go inside the machine with no problems.

 

[So]

Oh, and I'm a 3rd year EE interning @ the power company. I've never heard of any major problems with birds + transmission lines. AFAIK this guy is a crank who no power co. has any interest in.

 

[spidey07]

3. I think we can agree that from a magnetic perspective, humans are basically the same as a big bird. An MRI machine makes a magnetic field many orderes of magnitude bigger than a powerline, so huge that it has been known to drag huge oxygen tanks across the room, but people, so long as they have no ferromagnetic materials on them, can go inside the machine with no problems.

I don't really think we can navigate using our internal compasses to the same spot in the south every year, so I believe we are very different.

 

[Eli]

Originally posted by: spidey07

3. I think we can agree that from a magnetic perspective, humans are basically the same as a big bird. An MRI machine makes a magnetic field many orderes of magnitude bigger than a powerline, so huge that it has been known to drag huge oxygen tanks across the room, but people, so long as they have no ferromagnetic materials on them, can go inside the machine with no problems.

I don't really think we can navigate using our internal compasses to the same spot in the south every year, so I believe we are very different.

Actually....

Humans' sense of direction is linked to iron deposits in the nose.

We have the ability, it's just very, very weak.

 

[So]

Originally posted by: spidey07

3. I think we can agree that from a magnetic perspective, humans are basically the same as a big bird. An MRI machine makes a magnetic field many orderes of magnitude bigger than a powerline, so huge that it has been known to drag huge oxygen tanks across the room, but people, so long as they have no ferromagnetic materials on them, can go inside the machine with no problems.

I don't really think we can navigate using our internal compasses to the same spot in the south every year, so I believe we are very different.

I knew someone would try this argument,

You might be able to argue that birds internal compass may be messed up by powerlines but that has no connection whatsoever to how magnetic their body is. All they are doing is detecting the orientation of the earth's magnetic field, their blood and body is still clearly not ferromagnetic. For the purposes of this argument, the birds are the same.

I DARE anyone on this forum to get a magnet to stick to their pet cockatoo.

 

[OulOat]

Originally posted by: So

Originally posted by: spidey07

3. I think we can agree that from a magnetic perspective, humans are basically the same as a big bird. An MRI machine makes a magnetic field many orderes of magnitude bigger than a powerline, so huge that it has been known to drag huge oxygen tanks across the room, but people, so long as they have no ferromagnetic materials on them, can go inside the machine with no problems.

I don't really think we can navigate using our internal compasses to the same spot in the south every year, so I believe we are very different.

I knew someone would try this argument,

You might be able to argue that birds internal compass may be messed up by powerlines but that has no connection whatsoever to how magnetic their body is. All they are doing is detecting the orientation of the earth's magnetic field, their blood and body is still clearly not ferromagnetic. For the purposes of this argument, the birds are the same.

I DARE anyone on this forum to get a magnet to stick to their pet cockatoo.

Oh #@$%#(, my cockatoo imploded!!!!:|:|:|:|

 

[So]

^--- it had to be said.

 

[element]

Birds sitting on powerlines really are floating over them though. Just like when you sit in a chair you're floatinga tiny distance above it.

The atoms are repelled by the repulsive forces of the electrons. The atoms never actually touch each other.