Elementary, my dear
Textbooks can be very deceiving. I had a talk today that I've had to do many times in the past. It was about nuclear density, how it relates to radioactivity and weak and strong nuclear forces. One of the reasons I suspect this is so often not understood is that chemistry textbooks insist on making atoms look like planet/moons systems. The scale is way, way off since the electron shell is over a trillion times larger than the nucleus. There's just not enough emphasis on how huge the essentially mass-less part of the atom is versus the nucleus. Anyway, this led into a talk on how dense the nucleus is and that objects never actually touch each other--we just bounce off the electron shells of other objects. I suspect the kid still doesn't believe what I told her but I blame textbooks! And don't get me started on the particle versus wave thing. Textbooks seem to emphasize particles because they're easier to illustrate and explain. At least that's my perception.