Changes

*Some alpha particles were deflected by significant amounts.

*Some alpha particles were deflected by significant amounts.

*'''Occasionally some alpha particles were reflected.'''  That is, they bounced back toward the alpha source.

*'''Occasionally some alpha particles were reflected.'''  That is, they bounced back toward the alpha source.

The then-prevailing "plum pudding" model of the atom posited that atoms were essentially "soft", with protons distributed throughout, and electrons running around with them.  The alpha particles would not have bounced back under that model.  The experiment showed that the positive charge, that is, the protons, must have been concentrated in one location (the nucleus) that was "hard".  If the alpha particle got too close to that, the electric force repelling it would be so enormous that the alpha particle could turn around and go back.

The then-prevailing "plum pudding" model of the [[atom]] posited that atoms were essentially "soft", with protons distributed throughout, and electrons running around with them.  The alpha particles would not have bounced back under that model.  The experiment showed that the positive charge, that is, the protons, must have been concentrated in one location (the nucleus) that was "hard".  If the alpha particle got too close to that, the electric force repelling it would be so enormous that the alpha particle could turn around and go back.

So this experiment established the nuclear model of the atom.  The atom is almost entirely empty space.

So this experiment established the nuclear model of the atom.  The atom is almost entirely empty space.