What is Quantum physics ?

Question

can you explain it so an ordinary person can tell his kids what it is ?

Answer 1

Wow! Quantum physics is far too complicated and complex to summarize here. There are a multitude of phenomena associated with it too.

The characteristics described by quantum physics apply at spatial sizes smaller than 1.6^ minus 35 meters (..about 10^ 20 meters smaller than a proton..) Most of quantum physics deals with how subatomic particles and spacetime behave at such minute spatial sizes.

Answer 2

quantum physics describes how very very small things behave (on the order of atoms or smaller) because at atomic scales, the regular physics rules don't apply anymore. See the wikipedia article for more detail.