I mentioned in my post on Henry Boltinoff that the exceptions to the DC mags that carried his gags included the comics edited by Julius Schwartz. Schwartz preferred educational fillers like this one:
Does anybody really believe that a steel ball would bounce higher than a rubber ball of the same size? Maybe if you dropped them both on a rubber surface, but not on a sidewalk as shown in that panel.
These features appeared regularly in Green Lantern. Flash, of course, had Amazing Speeds:
When Schwartz took over the editor's desk on Batman he emphasized detective-oriented fillers like this one:
While the Atom, no surprise, featured tiny factoids: