Does alumina float?
Does alumina float?
No
3,900 kg/m³ against water's 1,000
Alumina sinks. At 3,900 kg/m³ it is 3.90 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
- 3,900 kg/m³ (3,700–3,980)
- Relative to fresh water
- 3.900×
- Floats in fresh water
- No
- Floats in seawater
- No
Compared with other materials
| Material | Density | Floats |
|---|---|---|
| asphalt (hot-mix) | 2,350 kg/m³ | No |
| concrete | 2,400 kg/m³ | No |
| porcelain | 2,400 kg/m³ | No |
| limestone | 2,450 kg/m³ | No |
| reinforced concrete | 2,500 kg/m³ | No |
| soda-lime glass | 2,500 kg/m³ | No |
| tempered glass | 2,500 kg/m³ | No |
| quartz | 2,650 kg/m³ | No |
| aluminum | 2,700 kg/m³ | No |
| aluminum 6061 | 2,700 kg/m³ | No |
Common questions
- Does alumina float in water?
- No — at 3,900 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
- Alumina properties Density, melting point, strength
- Does air float? Yes
- Does expanded polystyrene foam float? Yes
- Does rigid polyurethane foam float? Yes
- Does EVA foam float? Yes
- Does balsa float? Yes
- Does corrugated cardboard float? Yes
- Does cork float? Yes
- Does western red cedar float? Yes
Sources
- Typical range compiled from manufacturer specifications — At One Place