How it works
Density is mass per unit volume. It identifies materials (aluminum is about 2.70 g/cm³, steel about 7.85 g/cm³) and tells you whether something will float.
Grams per cubic centimeter equal grams per milliliter, and 1 g/cm³ equals 1,000 kg/m³. Water is close to 1 g/cm³ at room temperature, so the density in g/cm³ is almost the same as specific gravity.
To find the volume of an irregular object, submerge it in water and measure the displaced volume, then weigh it and divide.
Formula
ρ = m ÷ V m = ρ × V V = m ÷ ρ
Questions people ask
What is the density of water?
About 0.99997 g/cm³ at 4 °C (its maximum) and 0.99705 g/cm³ at 25 °C. Seawater is about 1.025 g/cm³.
What is specific gravity?
The ratio of a material’s density to that of water. It has no units. A specific gravity above 1 means the material sinks in fresh water.
How do I convert g/cm³ to lb/ft³?
Multiply by 62.428. Steel at 7.85 g/cm³ is about 490 lb/ft³.