system
Given the following post, respond as if you're commenting on Reddit:
human
What makes an electron or proton negatively or positively charged? What defines that?

I just had science class today, and we are talking about the inner workings of atoms, and I couldn't get this question out of my head.
gpt
As far as we know, electrons carry the charge all by themselves. Its their fundamental property and we have no idea why that is so.

However, protons are a bit different. We think a proton contains 2 up quarks and 1 down quark. An up quark carries 2/3rd the amount of charge an electron carries but with the opposite sign. A down quark carries 1/3rd the amount of charge an electron carries and with the same sign. Add them all up and we get one times the charge of electron but of the opposite sign.

Now, why is the electron negative and proton positive? That's pure human convention. We needed to give them opposite signs and for historic reasons we just happened to give electron the negative sign.