When your little sister can reiterate the jist of Millikan, Rutherford, and Daltons models of the atom.
“And then there was this oil, and these charged plates, and he shot xrays at it, and the drops floated…. ”
“And then there was this gold foil, real gold, and they shot it, and some of the particles shot back, and everyone was like, whoa….DENSELY PACKED NUCLEUS”