Jump to content

Recommended Posts

Posted (edited)
12 minutes ago, joigus said:

The actual reason why electricity cannot be "grounded" --or, if you will, there is no similar principle for gravity, as there is for electricity, as "grounding of a distribution of charges and currents"-- is that electricity is polar, while gravity is not. Charges can be positive or negative, while mass is always positive and the interaction is always attractive.

Positive distributions of charge have a natural place to set the zero for the potential: Spatial infinity.

Negative distributions of charge have a natural place to set the zero for the potential: Spatial infinity.

Distributions of mass have a natural place to set the zero for the potential: Spatial infinity.

This is because, far enough away from the distribution of either charge or mass, the field always "looks" monopolar- except for radiation. You can see this from a totally general multipolar expansion of the electrostatic field. Gravity, as we know, is described by GR, but the pre-relativistic approach is enough for the purposes of this discussion. If anything, consideration of GR would make the analogy even more implausible.

For electric charge, actually, there are deep principles of physics that tell us that far enough away from the distribution of charge, the monopolar term must go to zero. This is not exactly equivalent to what a recent poster said that "total charge must be zero," or something to that effect. It just means that, at large enough distances, charges will screen each other so as to make the electrostatic field go down at large enough distances. IOW: You just cannot take excess positives to one region and excess negatives to another at arbitrarily large distances.

The Earth is a relatively good conductor and can take as many excess electrons as regular physical processes near its surface can produce without subtantially changing its global electric charge --which is zero. So you can set its electrostatic potential to V=0, while keeping consistent with V=0 at spatial infinity

You cannot do that with gravity... The upshot --if nothing else was understandable-- is: Gravity cannot be cancelled.

I've read before that lightning can be a positive or a negative charge and the charge that comes from the ground to connect with the lightning is the opposite charge ? 

When we rub a balloon and create an electrostatic charge , the balloon can be stuck to a vertical wall , the static energy being grounded by the wall . 

An atom has an electron and a proton , these both have opposite charges .  Why are the Coulombs of force ignored by science just because they measure 0 voltage ? 

A force isn't a voltage . 

 

Edited by JustJoe
Posted
5 minutes ago, JustJoe said:

I've read before that lightning can be a positive or a negative charge and the charge that comes from the ground to connect with the lightning is the opposite charge ? 

What you've probably read is that excess electrons go upwards, so lightning goes from the surface of the Earth to the atmosphere, rather than the other way around. It's electrons that move, not protons.

10 minutes ago, JustJoe said:

Why are the Coulombs of force ignored by science just because they measure 0 voltage ? 

A force isn't a voltage . 

I don't understand the question. Coulombs don't measure force; they measure electric charge. Science ignores force??? 

Posted
Just now, joigus said:

 

I don't understand the question. Coulombs don't measure force; they measure electric charge. Science ignores force??? 

Yes science ignores the forces . An electron and proton  are said to be attracted to each other because opposite charges attract each other . Ok, let us consider a proton and an electron that are joined together . 

Does the electron charge still have an attractive force to free protons ? 

Does the proton charge still have an attractive force to free electrons ? 

My answer is yes , why would the force be nullified just because they are now joined together ? 

 

 

 

 

 

Posted
4 minutes ago, JustJoe said:

My answer is yes , why would the force be nullified just because they are now joined together ? 

The force is "nullified" --that's not the proper terminology though-- because of quantum mechanics. The electron keeps at a distance because it cannot get closer due to quantum constrictions.

Heisenberg's uncertainty principle.

Posted
2 minutes ago, joigus said:

The force is "nullified" --that's not the proper terminology though-- because of quantum mechanics. The electron keeps at a distance because it cannot get closer due to quantum constrictions.

Heisenberg's uncertainty principle.

Isn't the electron and proton unbalanced in charge magnitude which would account for motion and a 0 radius ? 

Nullified is a terrible word to use , I should of said equalised . 

Posted

Equalised? I don't know what you mean. Electron attracts proton, proton attracts electron. They get as close as they can without contradicting Heisenberg's uncertainty principle. What is equalised there? I don't understand. Physics has a language that refers to a mathematical formulation. What is equal to what?

The concept of force is less useful in quantum mechanics because we have stationary states, which can't be understood in terms of force. Many other quantum phenomena can't be understood in terms of force, like degeneracy pressure, or tunneling, or pair production... There are many things that cannot be understood in terms of force.

Is that better?

Posted
50 minutes ago, Lorentz Jr said:

I think by "neither homogeneous nor isotropic" he just means "not flat". Those are properties.

No, homongenous and flat have greater significance in SR.

Here is a good piece from Turner (University of Sussex)

turner1.jpg.498b15b255a16200c5083f4c34f22c21.jpg

 

Posted (edited)
31 minutes ago, JustJoe said:

Does the electron charge still have an attractive force to free protons ? 

Does the proton charge still have an attractive force to free electrons ? 

My answer is yes , why would the force be nullified just because they are now joined together ?

They're not. The electron and the proton both contribute to the net electric field created by the atom. The electron's charge and center of mass are exactly the same (and opposite for charge) as the proton's. So the total force exerted by a hydrogen atom on a distant charge Q is

[math]F = k_e Q(\frac{(+q) + (-q)}{r^2}) = k_e Q(\frac{q-q}{r^2}) = k_e Q(\frac{0}{r^2}) = 0[/math]

Edited by Lorentz Jr
Posted
1 minute ago, joigus said:

Equalised? I don't know what you mean. Electron attracts proton, proton attracts electron. They get as close as they can without contradicting Heisenberg's uncertainty principle. What is equalised there? I don't understand. Physics has a language that refers to a mathematical formulation. What is equal to what?

The concept of force is less useful in quantum mechanics because we have stationary states, which can't be understood in terms of force. Many other quantum phenomena can't be understood in terms of force, like degeneracy pressure, or tunneling, or pair production... There are many things that cannot be understood in terms of force.

Is that better?

When a proton and electron become joined , one charge cancels out the other charge , making it a neutral particle . This it what I was attempting to say , but messed it up .

You explain - '' Electron attracts proton, proton attracts electron.'' 

I asked , when a proton and electron is joined , why is the attractive force then ignored ? 

 

 

 

 

3 minutes ago, Lorentz Jr said:

They're not. The electron's charge and center of mass are exactly the same (and opposite for charge) as the proton's. So the total force exerted by a hydrogen atom on distant charges is

ke(+q)+(q)r2=ke0r2=0

I don't know a great deal about math but why have you used charge rather than a force ? 

Shouldn't it be proton force + electron force divided by radius squared ? 

 

 

 

Posted (edited)
10 minutes ago, JustJoe said:

I don't know a great deal about math but why have you used charge rather than a force ? 

Shouldn't it be proton force + electron force divided by radius squared ?

Coulomb's law

No, the general expression for the classical electrostatic force is [math]F = \frac{kQq}{r^2}[/math], where q is the net charge on the atom, which is zero.

 

Edited by Lorentz Jr
Posted (edited)
15 minutes ago, JustJoe said:

When a proton and electron become joined , one charge cancels out the other charge , making it a neutral particle . This it what I was attempting to say , but messed it up .

As @Lorentz Jr told you, the CoM of e- and proton coincide. If e- is in an s-wave, the charge distribution has no polarity. Is that "nullified" enough for you?

If the electron is excited to a state with angular momentum, a slight polarity appears. So at very short distances you would see the electron "sticking out."

You see, there are details --many of them-- that you're missing. So your picture is probably very imprecise on many accounts...

EDIT: No polarity, sorry. A displacement of charge density, but no polarity.

I find it very difficult to understand what you mean, honestly.

Edited by joigus
correction
Posted
1 minute ago, Lorentz Jr said:

Coulomb's law

No, the general expression for the classical electrostatic force is F=kQqr2 , where q is the net charge on the atom, which is zero.

 

Yes I understand the net charge of an atom is zero but what is the net force ? 

 

2 minutes ago, joigus said:

As @Lorentz Jr told you, the CoM of e- and proton coincide. If e- is in an s-wave, the charge distribution has no polarity. Is that "nullified" enough for you?

If the electron is excited to a state with angular momentum, a slight polarity appears. So at very short distances you would see the electron "sticking out."

You see, there are details --many of them-- that you're missing. So your picture is probably very imprecise on many accounts...

 

Yes I admit there is probably many intricate details I don't know but I think my generalised understanding is ok . 

Posted (edited)
4 minutes ago, JustJoe said:

Yes I understand the net charge of an atom is zero but what is the net force ?

The net force exerted by the atom on an external charge Q is

[math]F = \frac{kQ(q-q)}{r^2} = \frac{kQ(0)}{r^2} = \frac{0}{r^2} = 0[/math]

Edited by Lorentz Jr
Posted (edited)
1 hour ago, Lorentz Jr said:

It's similar to what Maxwell worked on back in the late 1800s, except it's more complicated because there are almost 20 known fields now. Maxell's model had little mechanical things of some kind spinning inside cells with rollers around them to allow the spinning. I'm still reading about Penrose's ideas, but I have to guess that they're based on the eiωt terms in quantum wave functions, since they obviously at least suggest some kind of spinning activity.

You would likely Sir Roger Penrose "100 roads to Reality of interest. Just an FYI so we don't derail this thread. The term you posted is commonly applied in QFT wavefunctions just an FYI

Edited by Mordred
Posted

Anyway, charge can be grounded. Gravity can't. You would have to make all mass go to infinity to "ground" mass.

I find it impossible to think of an analogue for a conductor in the case of gravity.

Posted
1 minute ago, Mordred said:

You would likely Sir Roger Penrose "100 roads to Reality of interest.

I just started "Fashion, Faith, and Fantasy". Maybe I'll try "100 Roads" sometime.

Posted (edited)
6 minutes ago, Lorentz Jr said:

The net force exerted by the atom on an external charge Q is

F=kQqr2=kQ(0)r2=0r2=0

That can't be correct because of several reasons 

1) An electrostatic charged balloons surface sticks to a vertical wall 

2)Electrical energy is grounded 

3)Lighting strikes are generally directed towards the ground 

A wall is electrically neutral , how can a balloon stick to a vertical wall unless the wall was attracting the balloon ?

 

 

 

 

 

 

Edited by JustJoe
Posted (edited)
4 minutes ago, JustJoe said:

That can't be correct because of several reasons

Do you want to know the force between the proton and the electron, or the total force they exert together on other charges? I told you the answer to the first question (it's zero because the charges are equal and opposite), and @joigus told you the answer to the first one: Quantum mechanics prevents the electron from getting any closer to the proton than it does in its atomic orbital, because of the Heisenberg uncertainty principle.

Edited by Lorentz Jr
Posted
2 minutes ago, Lorentz Jr said:

Do you want to know the force between the proton and the electron, or the total force they exert together on other charges? I told you the answer to the first question (it's zero because the charges are equal and opposite), and @joigus told you the answer to the first one: Quantum mechanics prevents the electron from getting any closer to the proton than it does in its atomic orbital, because of the Heisenberg uncertainty principle.

Perhaps I don't understand your answers because I am not good at the math you provided . 

I want to know how much force an atom applies on another atom , I explain this force in being two seperate forces that have joined together to make another force . 

In trying to explain differently , how much attractive force does a human finger apply on the plasma in a plasma ball ? 

 

 

 

Posted (edited)
20 minutes ago, JustJoe said:

I want to know how much force an atom applies on another atom , I explain this force in being two seperate forces that have joined together to make another force .

That's the question I answered. The net force is from two equal and opposite forces that have joined together to make another force that adds up to zero.

F + (-F) = F - F = 0.

There can be nonzero net forces between atoms if they're right next to each other in the same solid or liquid. For instance, the Van der Waals force is caused by separations of the charges in each atom so opposite charges in the two atoms get closer to each other and attract each other. Hydrogen bonding is a similar phenomenon that occurs in water because the charge is already distributed unevenly between the hydrogen and oxygen atoms. That's why water isn't as volatile as gasoline.

Edited by Lorentz Jr
Posted
11 minutes ago, JustJoe said:

I want to know how much force an atom applies on another atom , I explain this force in being two seperate forces that have joined together to make another force . 

You definitely need quantum mechanics to understand how atoms stick together. They are not electrostatic forces, as a chlorine atom attracts a sodium atom for reasons other than electrostatic force. They stick together because of a quantum equilibrium. With old ideas about force you can cover only so much ground. I'm sorry. 

Posted (edited)
4 minutes ago, joigus said:

They stick together because of a quantum equilibrium.

Is that really significant? They're attracted electrostatically, and they're kept apart because of the Pauli exclusion principle. How does quantum mechanics contribute to their mutual attraction in a way that differs significantly from Coulomb's law?

Edited by Lorentz Jr
Posted
3 hours ago, JustJoe said:

Doesn't all matter contain electrical charge because of the proton and electron ? 

No. There are massive uncharged particles, such as neutrinos 

Dark matter, though we lack details of what it is, we also know what it isn’t: it is also uncharged, and not made up of neutrons and protons

2 hours ago, JustJoe said:

A speculation doesn't require supporting evidence

 

Posted
7 minutes ago, Lorentz Jr said:

Is that really significant? They're attracted electrostatically, and they're kept apart because of the Pauli exclusion principle. How does quantum mechanics contribute to their mutual attraction in a way that differs significantly from Coulomb's law?

Yes, it is. A neutral chlorine atom has zero charge. So does a neutral sodium atom. But they stick together because sodium "donates" its extra electron (the 3s1 electron), which is very loose, for quantum-mechanical reasons, while the incomplete 3p5 level of sodium is much more stable with an extra electron. Ionic bonds are electrostatic in nature, but not because the original atoms are charged. It's a matter of quantum stability vs electrostatic attration, so to speak. The chemical bond does not happen because of electrostatic unbalance, but because atoms create these stable "rooms" for the electrons to be in. Atoms with similar electronegativity create a common orbital, in which to share electrons. That's the essence of the covalent bond. While transition metals create gigantic orbitals to cut loose their extra electrons. Those are the conduction bands.

A salt crystal is neutral overall though, same as metals, and covalent substances. Electric unbalance for macroscopic samples of matter is a tiny, tiny percent.

Electron and proton are not kept apart because of the exclusion principle. The exclusion principle is valid for identical particles. Electron and proton are very far from identical. They're kept apart because of the HUP.

One thing is attraction proton-electron in the hydrogen atom (electrostatic), and another thing is atom-atom attraction. I was addressing @JustJoe's request,

46 minutes ago, JustJoe said:

I want to know how much force an atom applies on another atom ,

(My emphasis.)

Those are different phenomena.

Posted (edited)
31 minutes ago, joigus said:

they stick together because sodium "donates" its extra electron (the 3s1 electron), which is very loose, for quantum-mechanical reasons, while the incomplete 3p5 level of sodium is much more stable with an extra electron. Ionic bonds are electrostatic in nature, but not because the original atoms are charged.

Right, of course. That was my point.

31 minutes ago, joigus said:

Electron and proton are not kept apart because of the exclusion principle. The exclusion principle is valid for identical particles.

Sorry. I thought you were talking about electrons and protons interacting with each other in individual atoms.

Edited by Lorentz Jr

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.