At One Place

Does water float?

Does water float?
No
1,000 kg/m³ against water's 1,000

Water sinks. At 1,000 kg/m³ it is 1.00 times denser than water.

Why

Floating is decided by density alone — mass divided by volume — compared against the fluid. Weight has nothing to do with it directly: a 200-tonne ship floats and a 2-gram pebble sinks, because the ship encloses enough air to bring its average density below that of water. That is also the only reason a steel hull works.

The numbers

Density
1,000 kg/m³ (958–1,000)
Relative to fresh water
1.000×
Floats in fresh water
No
Floats in seawater
Yes

Compared with other materials

Material Density Floats
spruce 430 kg/m³ Yes
pine 500 kg/m³ Yes
Douglas fir 530 kg/m³ Yes
mahogany 590 kg/m³ Yes
plywood 600 kg/m³ Yes
black walnut 610 kg/m³ Yes
OSB 640 kg/m³ Yes
particleboard 650 kg/m³ Yes
teak 655 kg/m³ Yes
ash 675 kg/m³ Yes

Common questions

Does water float in water?
No — at 1,000 kg/m³ it is denser than water's 1,000.
Does weight decide whether something floats?
No, density does. A 200-tonne ship floats and a small pebble sinks, because the ship encloses enough air to bring its average density below water.

Related pages

Sources

  1. United States Geological Survey — USGS (Public domain (US Government))

How these figures are compiled and checked