Electrons repel one another with a force whose size varies as the inverse square of the distance between them. Protons repel each other in the same way. However, electrons and protons attract each other. We describe this effect by saying that all the electrons have an electric charge, -q, and all the protons have a charge, +q. We say that “Like charges repel and opposite charges attract”.

This provides us with rules to say what will happen when electrons (and protons) interact. Despite this it remains a puzzle for particle physicists, quantum mechanicians, drunken philosophers, and other dome-brains to argue about just what this ‘charge’ really is...

We're lucky that electric charge works the way it does. If the attraction between electrons and protons vanished then our universe would literally fall apart!

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