What is the density of water?

Pure water at 4°C has a density of exactly 1 g/cm³ or 1000 kg/m³.

Why do some objects float?

Objects float when their density is less than the fluid they're in. Wood (0.5 g/cm³) floats on water (1 g/cm³).

Density Formula on CalcAll — free educational content with detailed examples.

What is the density of water?: Pure water at 4°C has a density of exactly 1 g/cm³ or 1000 kg/m³.
Why do some objects float?: Objects float when their density is less than the fluid they're in. Wood (0.5 g/cm³) floats on water (1 g/cm³).