Grounding, earths electrical field

[Agriias]

Hi guys,

I have a question. So we all know that voltages seek a path to ground and we hold that the ground is considered 0voltage (electrically neutral) compared to say a power line or a lightning bolt. The hot wire or lightning will seek to balance their charges out and equalize.

However, It has occurred to me that the earth has its own electromagnetic field and electrical currents and we aren't effected by them since they permeate everything around us and we are essentially at zero potential in most cases to the earths voltage.. In the same way an airplane connects all of its metal parts so that you can never touch two conductors at different voltages and get shocked.

This got me thinking.. when we say that higher voltage moves towards lower voltage/ground Is that really semantics? Is it in reality the opposite and lower voltages are drawn to the stronger electrical force in the same way that the moon is drawn to the stronger gravitational force of the earth?

I hope that makes sense.

Thanks,
Agriias

 

[Gryd3]

Hi guys,

I have a question. So we all know that voltages seek a path to ground and we hold that the ground is considered 0voltage (electrically neutral) compared to say a power line or a lightning bolt. The hot wire or lightning will seek to balance their charges out and equalize.

However, It has occurred to me that the earth has its own electromagnetic field and electrical currents and we aren't effected by them since they permeate everything around us and we are essentially at zero potential in most cases to the earths voltage.. In the same way an airplane connects all of its metal parts so that you can never touch two conductors at different voltages and get shocked.

This got me thinking.. when we say that higher voltage moves towards lower voltage/ground Is that really semantics? Is it in reality the opposite and lower voltages are drawn to the stronger electrical force in the same way that the moon is drawn to the stronger gravitational force of the earth?

I hope that makes sense.

Thanks,
Agriias

Depends on the convention you are talking about.
Look up conventional vs electron current flow.

 

[Arouse1973]

Hi guys,

I have a question. So we all know that voltages seek a path to ground and we hold that the ground is considered 0voltage (electrically neutral) compared to say a power line or a lightning bolt. The hot wire or lightning will seek to balance their charges out and equalize.

However, It has occurred to me that the earth has its own electromagnetic field and electrical currents and we aren't effected by them since they permeate everything around us and we are essentially at zero potential in most cases to the earths voltage.. In the same way an airplane connects all of its metal parts so that you can never touch two conductors at different voltages and get shocked.

This got me thinking.. when we say that higher voltage moves towards lower voltage/ground Is that really semantics? Is it in reality the opposite and lower voltages are drawn to the stronger electrical force in the same way that the moon is drawn to the stronger gravitational force of the earth?

I hope that makes sense.

Thanks,
Agriias

I think you mean current and not voltage. Current will form a loop which will return to its source. We generally use conventional current where the direction is from the highest potential to the lowest potential. But it is actually the other way. Don't get too hung up on this, we are sort of stuck with it now as everything has evolved around this concept.

Oh BTW the moon is moving away from us each year by about 4 cm, is this because gravity is changing? Interesting isn't it?

Adam

 

[Merlin3189]

" ... in the same way that the moon is drawn to the stronger gravitational force of the earth?"
But of course the Earth is also being drawn to the weaker gravitation of the moon. It is symmetric: the force on the Moon is exactly the same as the force on the Earth.
The attraction of the Moon can be seen in the movement of the sea - tides.

And I don't think the increasing separation of E&M is due to gravitational changes, but to changes in our speed of rotation. (Again linked to tides.) https://www.physicsforums.com/threads/distance-between-earth-and-moon-increasing.117378/

 

[davenn]

I have a question. So we all know that voltages seek a path to ground and we hold that the ground is considered 0voltage (electrically neutral) compared to say a power line or a lightning bolt.

not a very good way of looking at it .... its isn't neutral compared to a lightning bolt

The hot wire or lightning will seek to balance their charges out and equalize.

lightning part, yes ..... You need to take a couple of steps back and learn about what causes a lightning bolt
We wont consider what causes the build up of charge in the cloud at this time, just that during a storm it does
As the charge ( positive or negative ) builds up on the base area of the cloud, an oppositely polarised charge builds up on the ground
This creates an electric field between the 2, across the air dielectric. When the electric field builds up enough to reach the break down point of that dielectric, we get a lightning zap through the air.

Note some discharges are from the ground up to the cloud, some are from the cloud to ground
Sometimes it may be a negatively charged cloud base to a positively charged ground point, sometimes the other way around

Dave

 

[Agriias]

The upward lightning is cool. I didn't know about that. Have they determined why it happens? Does it have to do with whether the ground is positive or negative compared to the cloud?

I get that lightning is caused by ionization, but I guess the comparison is that both seek to ground out its just when its a powerline it will continuously do so as long as the generator is running.

 

[Gryd3]

The upward lightning is cool. I didn't know about that. Have they determined why it happens? Does it have to do with whether the ground is positive or negative compared to the cloud?

I get that lightning is caused by ionization, but I guess the comparison is that both seek to ground out its just when its a powerline it will continuously do so as long as the generator is running.

Not quite... You could run your own generator... and if neither the the hot or neutral were tied to ground, it would not attempt to 'ground' out to earth.
Current flow requires a circuit. a circuit to flow and return.
Static is different... a charge builds up on one surface/region and discharges into a another surface/region with a smaller charge.

 

[davenn]

.............a charge builds up on one surface/region and discharges into a another surface/region with a smaller charge.

.... with a smaller or an opposite charge

 

[davenn]

I get that lightning is caused by ionization, but I guess the comparison is that both seek to ground out its

no, as I said, it occurs when there is a build up of opposite charges
no, as has been explained nothing is grounding out anything. there is just a balancing out of charges

you seem to be a little fixated with this incorrect "grounding out" process

Dave

 

[Arouse1973]

" ... in the same way that the moon is drawn to the stronger gravitational force of the earth?"
But of course the Earth is also being drawn to the weaker gravitation of the moon. It is symmetric: the force on the Moon is exactly the same as the force on the Earth.
The attraction of the Moon can be seen in the movement of the sea - tides.

And I don't think the increasing separation of E&M is due to gravitational changes, but to changes in our speed of rotation. (Again linked to tides.) https://www.physicsforums.com/threads/distance-between-earth-and-moon-increasing.117378/

Hey Merlin

I knew that gravity was not the cause, I was wondering if he did. I suppose that's the problem with question marks, they sometimes get interpreted as needing knowledge rather than asking if someone has an idea about something.

The earth is slowing down but do you know why? and why should the moon be further away. Sorry I shouldn't be going off topic. Dave will smack my hands, again

Adam

 

[Arouse1973]

not a very good way of looking at it .... its isn't neutral compared to a lightning bolt



lightning part, yes ..... You need to take a couple of steps back and learn about what causes a lightning bolt
We wont consider what causes the build up of charge in the cloud at this time, just that during a storm it does
As the charge ( positive or negative ) builds up on the base area of the cloud, an oppositely polarised charge builds up on the ground
This creates an electric field between the 2, across the air dielectric. When the electric field builds up enough to reach the break down point of that dielectric, we get a lightning zap through the air.

Note some discharges are from the ground up to the cloud, some are from the cloud to ground
Sometimes it may be a negatively charged cloud base to a positively charged ground point, sometimes the other way around

Dave

And not forgetting cloud to cloud

Adam

 

[davenn]

And not forgetting cloud to cloud

Adam

yup