Natural universe - Science can say how a guitar string creates sound when plucked, but it can say little about the aesthetic value of music. Science can say nothing outside it's realm of expertise, in regard to ethics, morality, and the supernatural. Science is more about reducing uncertainty then stating things as hard cold fact. Problem or question based on observation. Must be testable.
Objects fall toward the ground when dropped.
The two balls will hit the floor at the same time. The only variable in the experiment is difference in mass. Otherwise both balls are the same. The lighter ball serves as our control. Both balls hit the floor at the same time.