r/chemistry • u/Primarch_escapist21 • 1d ago
What actually is charge
Non-Chemist here (so bare with me) what is charge, how does it work and how does positive and negative charge come about (mainly how do subatomic particles be charged
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u/Alkynesofchemistry Organic 1d ago
It’s an intrinsic property of particles. Just like mass and color and spin etc., trying to explain intrinsic properties of subatomic particles in words doesn’t work very well. At the scale of quantum, there is only real understanding through math.
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u/TheSpeckledSir 1d ago
In materials big enough for you to see with your eyes, charge means that there is an imbalance between the number of protons and the number of electrons available. Normally, these counteract each other. So, if you end up with too many or too few electrons, you'll get a negative or positive charge respectively.
Subatomic particles like protons and neutrons get their charge (or lack thereof) because they are made of even smaller particles (quarks) that carry charge themselves. Electrons are like quarks, they don't seem to be made up of smaller bits.
As for those quarks, they are just charged because they are. If they were not charged they would be something else besides a quark. If there is a deeper "why" than that, whoever discovers it is almost certainly going to recieve a Nobel prize.
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u/TGSpecialist1 1d ago
Also, elementary charge isn't actually elementary, quarks can have a charge of ±2/3 e for u,s,t or ∓1/3 e for d,c,b so if we were consistent electrons would have a charge of -3.
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u/TheSpeckledSir 1d ago
I don't think there's anything inconsistent about setting the elementary charge to 1.
At least, nothing more inconsistent than using meters, seconds, AMU, or coloumbs.
It's just a unit.
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u/stationarycommotion 1d ago edited 1d ago
If you’re asking this question ontologically, it is philosophical and is the same kind of thing as asking why is there something rather than nothing.
The other answer is that the maths of quantum field theory (QFT) says there has to be charge for some quantum fields otherwise the model breaks down. Which really just means that those fields are coupled to the electromagnetic field. So if there’s a particle in those fields, such as the electron field, that particle WILL be mathematically linked to the electromagnetic field and therefore electromagnetic force interactions are seen.
The fields that give charged particles aren’t inherently positive or negative charge either. The electron field could just as easily carry a positron (antimatter), which is identical to an electron but with the equal and opposite charge. We don’t know why the universe is made of matter instead of antimatter, but if atoms had positrons and anti protons, instead of electrons and protons, chemistry would work exactly the same and we still could’ve just as easily called the positrons electrons and still wonder why the universe has more matter than antimatter even though from our point of view that would be a universe made of anti matter.
But remember that we created the maths of QFT from things we observed, experiments done, in the natural world. It’s a philosophical debate whether we discover the maths like it’s a hidden code of reality, or we invent the maths to describe patterns of reality. Most physics philosophers would probably say it just describes patterns.
Although maths has been powerful because it has allowed us to predict things we didn’t yet observe, like anti matter and the Higgs field, but that obviously could still just be because the mathless patterns of reality can be modelled so well when our theory is good enough.
So why there is charge in those particles at all is impossible to answer but based on our understanding of quantum field theory there was no other possible way given the actual reality we find ourself in. The difference between “positive” and “negative” charge is really just language, they’re equal and opposite properties of particles that mean the particle has interactions via the electromagnetic field in one way or the other, and that’s just the way it is because maths.
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u/Mysterious_Cow123 1d ago
"Charge" is a property possed by subatomic particles. For example, Protons are defined to have "postive" and electrons "negative" charge.
They could've been called "moon loving" and "sun loving", was orginially called the "amber effect" and is just a name that stuck and because we now teach children those terms, its familiar.
Think about it more like water is wet. Water being wet is just a property it has by virtue of being water. Charge is something the particles have by their nature. Why? Ask god, not I.
For a more complete answer, I would direct you to r/askphysics or a healthy Wikipedia reading session.
Good luck
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u/Beginning-Sound1261 1d ago edited 11h ago
I disagree with people just saying “It just is.”
Physics has come a pretty long way, and quantum field theory has been pretty successful in deriving / explaining the standard model. This includes why there are certain fundamental properties particles have.
The math is complicated, but the fundamental properties essentially arise from applying Noether’s theorem on symmetries that we believe exist to wave equations.
Noether’s theorem is the statement that conserved quantities arise from fundamental symmetries. For charge we study U(1) symmetry. What that means is the physical observables of the particle is invariant of phase. If you demand that symmetry holds then a conserved quantity for that particle pops out (charge) and the force field (electric field) pops out to ensure the symmetry is preserved.
Edit: y’all some whiny bunch. I’m not going through to respond to people, who based off response alone, I can tell have never looked at the mathematics. But they can talk like they are experts in the field. Faux experts of reddit are fucking exhausting. I started typing this response and I was just like “Why am I taking time to respond to people who would rather waste time pretending to be experts in something for red arrows than just be curious and go learn about it.”
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u/Taeban 1d ago
But why those specific symmetries? Why not another set of symmetries? Why does electromagnetism exhibit a U(1) and not SU(3) like the strong force does?
Why did the Higgs Field have its symmetry broken in the way it did to give fundamental particles their intrinsic mass?
Why is it that c is c and not slightly higher or lower? Or h? Or G?
For now our answer really is "It just is that way."
I would love if we had a theory that told us why each of these constants and symmetries arise specifically, but we just don't.
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u/Beginning-Sound1261 1d ago
You can throw out the entire theory because it can’t explain everything we have ever observed in the history of the universe if you want. I’m not going to do that though.
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u/Sea_Goat_6554 18h ago
But that's just one more level. You're still saying that that symmetry "just is".
Ultimately, it's turtles all the way down. True wisdom is recognising that at some point we have to go "this is just how things are". We may one day find deeper truths, or we may never. But short of the universe turning out to be a simulation, the chances of finding the ultimate truly true truth of reality that explains everything seems low.
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u/chilidoggo 1d ago edited 1d ago
ELI5: Think of charge like when you have magnets. You have them together and they act like a normal piece of metal. You take them apart and they don't like that, and there is a force pulling them back together. That force is their charge trying to stay balanced. This force also works on individual atoms, and is kind of what enables all of chemistry. Magnets are technically different, but don't worry about that for now. You're only 5 after all.
Explaining to a high schooler: Atoms are made up of protons, neutrons, and electrons. These have, respectively: positive, neutral, and negative charges, simply because of the way they innately are, and all of chemistry and life comes about because electrons also are bound by other rules that cause atoms to interact and form molecules. So you can get atoms with a charge imbalance. Sodium chloride (salt), for example, comes about when the sodium loses an electron and the chlorine gains one. Their charge imbalance then binds them together into salt crystals.
Explaining to a college student: all of the above, but then also quantum mechanics to explain why that happens. But how did it come about? That's a hardcore physics question without a good answer. The simplest version that I like is that after the big bang, this was the version of the universe that was stable and the only way for matter to organize itself. But this remains as a big unanswered question. We understand electron behavior really well at this point, but we don't know their origin/history.
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u/mrmeep321 Surface 19h ago
The "why" behind charge is quite complicated, a bit out of the realm of chemistry, more of physics.
This video does a very good job at explaining it, would recommend watching the. Fair warning, it is about 3 hours long and very math heavy, but the intro should be a good basic explanation as to where charge actually comes from
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u/dipdotdash 10h ago
YouTube, Google, every ai model, every chemistry book, and instead you ask it here. Why? What reciprocal effort are you willing to invest?
People can't help themselves because they know the answer, but these kinds of zero effort questions should be deleted and redirected to Google, ime
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u/Primarch_escapist21 4h ago
Probably because I’m not trusting a clanker to give me a correct answer, YT doesn’t give it in layman’s terms and I’m not interested enough in chemistry to buy a chem book, now stop trying to gatekeep and let a simple man ask a as it turns out not so simple question
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u/claisen33 1d ago
This is not a chemistry question.
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1d ago
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u/chemistry-ModTeam 13h ago
Rule 6 - Zero-content material
No memes, rage comics, image macros, reaction gifs, or other "zero-content" material.
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u/anti-gone-anti 1d ago
There isn’t exactly a “how” to why subatomic particles have charge. They just do, it’s a fundamental property of matter that particles have masses and charges.