An iceberg floats in sea water with density 900 kg/m³ for ice and 1000 kg/m³ for water. The fraction of its volume below the surface is:

Since the same volume of fluid must pass every cross-section per second (continuity), the fluid speeds up where the pipe narrows; Bernoulli's equation then says this faster-moving fluid has lower pressure - the principle behind a venturi meter and an aircraft wing's lift.