Why do icebergs float in the ocean?
Short answer
Ice is less dense than liquid water, so buoyancy from seawater keeps part of an iceberg above the surface.
How it works
Most of an iceberg is underwater. The visible fraction depends on seawater density and the shape and density of the ice.
Key point
The practical point is this: The visible fraction depends on seawater density and the shape and density of the ice.