Children Are Source Of Embarrassment

[samalkhaiat]

Krab says; "If you only understand it mathematically, then you don't really understand it...". Sir can you be kind & explain to me (not to my 8 years old gaughter) what is local gauge invariance means & how it works in field theory? I would love to see a "qualitative" explanation as to how this principle introduces interaction into the theory.
Thank you for the broom example! Can you do the same thing with the symmetrical spinning top? & tell me who order the littile toy to balance its centre of mass?

 

[HallsofIvy]

You are aware, are you not, that children consider parents a source of embarassement?

 

[samalkhaiat]

You are absolutely right, We are guilty of double crime. We accuse our parents as well as our kids of being a source embarassement. Yet we manage to get away with it.