This also explains why, over time, more dense ("heavy") objects sink and less dense ("lighter") objects rise to the surface. This is because if two objects of the same size, but different mass, are accelerated to the same magnitude, the object with the greater mass has more inertia and force, and will displace the object with less mass.

It's one of the controlling aspects of weather phenomena, since cold air sinks and hot air rises (which creates clouds and rain). There's a neat kids physics experiment where you add multiple differently dense things to a tall clear container (stuff that can be shifted around, like dried rice, beans, foam peanuts, etc.), and shake the container. The greater density objects will sink to the bottom, and the lesser density objects will rise to the surface, creating clearly delineated layers.