The bearing turns sliding friction into rolling motion
A loaded tray would be difficult to swivel if its bottom had to scrape directly across the table or cabinet shelf. A Lazy Susan’s central bearing creates a small moving interface between the stationary base and the rotating top. In many designs, small balls roll between metal rings; the balls carry the load while allowing the upper surface to turn.
That rolling contact takes much less effort than dragging two broad surfaces against each other. A light push at the rim can therefore rotate a tray carrying several dishes. The rim also gives the push leverage: applying force farther from the center produces more turning effect than pushing close to the bearing.
Why the load still matters
The bearing does not make weight disappear. It must support the dishes and tray, and a heavier or unevenly loaded platform can be harder to start and stop. Placing heavier items nearer the middle helps keep the load balanced; items crowded at the edge put more strain on the support and can make the tray feel less steady.
The design’s useful compromise is simple: the bearing stays fixed in the middle, while the broad surface does the traveling. Instead of moving a bottle hand to hand, diners move the whole collection a short distance with one turn. That same arrangement works in cupboards, where a spin can bring a jar from the back to the front without requiring someone to reach blindly into the shelf.
