B Is there some electrical charge that is neither positive nor negative?

[ElectroMaster88]

I do not mean neutral electrical charge, but a forth kind (if exists)

I am in 9th grade, and someone asked the teacher if there is an electrical charge that is not positive, not negative and not neutral, maybe something in the middle of them.
The teacher said that there is a charge like that, but it's too advance for our level.

Is she right?
It just seems impossible because an electrical charge can be measured in numbers, and numbers can be just positive, neutral or negative.

 

[Orodruin]

No. There is no such electrical charge.

However, there are other charges related to other fundamental interactions such as strong and weak interactions. Those are not describable in the same fashion and certainly too advanced for 9th grade.

 

[jbriggs444]

The teacher said that there is a charge like that, but it's too advance for our level.

Is she right?
It just seems impossible because an electrical charge can be measured in numbers, and numbers can be just positive, neutral or negative.

In sub-atomic physics there are notions of "charge" other than the electric charge. This Wiki article seems a decent start.

Electrical charge is indeed numeric. It is quantized and can take on only (signed) integer values.

 

[anuttarasammyak]

Quarks have three kinds of color charge.
Read an article e.g. https://en.wikipedia.org/wiki/Quark#Strong_interaction_and_color_charge .

 

[vanhees71]

In sub-atomic physics there are notions of "charge" other than the electric charge. This Wiki article seems a decent start.

Electrical charge is indeed numeric. It is quantized and can take on only (signed) integer values.

It can only take integer multiples of the elementary charge, which since 2019 is used to define the SI unit of charge (Coulomb), setting $e=1.602176634 \cdot 10^{-19} \; \text{C}$.

 

[malawi_glenn]

Quarks have non-integer electric charge

 

[vanhees71]

True, but they cannot be observed as free particles but only in bound states which have integer multiples of the elementary charge.

 

[Ibix]

In sub-atomic physics there are notions of "charge" other than the electric charge. This Wiki article seems a decent start.

...although the fact that the summary starts talking about time invariant generators of symmetry groups does rather underline Orodruin's point that this is a bit beyond a 9th grade class.

 

[Orodruin]

...although the fact that the summary starts talking about time invariant generators of symmetry groups does rather underline Orodruin's point that this is a bit beyond a 9th grade class.

I merely underlined the teacher’s assertion if that is what she was talking about…

 

[malawi_glenn]

True, but they cannot be observed as free particles but only in bound states which have integer multiples of the elementary charge.

Yes, but color confinement is not implemented in the electroweak SM lagrangian and only arise once you assign SU(3) charges to the quarks. In fact, color confinement was motivated by the lack of experimental evidence not detecting fractional free electric charges. There are nothing in principle against having non integer fractional electric charges, as long as you make sure such theory is anomal free etc.

 

[SDL]

There are only two kinds of charge interaction - attraction and repulsion. This can be easily shown using axial symmetry of a system of two interacting point charges. You might be greatly surprised, but this fact itself does not mean that there are only two kinds of charges in the universe - "positive" and "negative". Let me give an illustration:

Imagine you set an experiment where you explore point charge interactions. Get a bin and put the first charge there. The second charge repels the first, put it to the same bin. The third one attracts the first two charges, it's a different kind of interaction, so it cannot be put to this bin. Take a second bin and put the charge there. Some time later we'll have two bins, each containing charges repelling each other and every charge from the first bin attracts to every charge from the second bin. Looks very usual, isn't it?

These are our well known charges named "positive" and "negative". But now we take the next charge from the environment with very interesting properties: it attracts to every charge from both bins. It cannot be put in either existing bin since it's demonstrating a different kind of interaction with charges in boths bins. Now we have nothing to do but to take a third bin for this charge. Also we have to choose a name for the new kind of charges, let it be "asterisk".

If we go on with collecting charges, finaly we'll end up with three bins, each containing charges repelling each other and every charge from either bin attracts to every charge from another one.

During the whole human history people have seen only charges that perfectly fit into only two bins, this is why we have only positive and negative charges nowadays. But nobody can state that a third kind of charges will not be discovered in the future. An existing theory in physics must describe all experiments ond observations performed. But think, if such discovery is made, we'll have to deny the future or just invent a new theory?

It just seems impossible because an electrical charge can be measured in numbers, and numbers can be just positive, neutral or negative.

No, the logic here is right opposite. We are able to represent charges as scalar algebraic values because we have only two kinds of charges, not vice versa. If there were more than two kinds, physicists would employ another way to mathematically express them.

 

[SDL]

It can only take integer multiples of the elementary charge, which since 2019 is used to define the SI unit of charge (Coulomb), setting $e=1.602176634 \cdot 10^{-19} \; \text{C}$.

To be exact, in classical electromagnetism charges are generally represented as some kind of "fluid" with a given continuous density distribution. Some discrete models like "point charge", "point mass", "infinitely thin charged surface", "infinitely thin long wire with current" are widely used and, strictly speaking, charge, current and mass density for them is expressed in terms of Dirac's delta function in order to generalize mathematical expressions. And also "elementary charge" is not a requirement here, but in quantum physics certainly is.