Information about things we can't see

How big is an atom?	How big is a nucleus?	How big is a proton?	How big is an electron?
What makes up an atom?	What makes up a nucleus?	What makes up a proton?	What makes up an electron?
What do we know about the strong force?	What do we know about the electromagnetic force?	What do we know about the weak force?	What do we know about the gravity force?