Density Calculator
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The relationship
Density is mass per unit volume — an intensive property, meaning it does not depend on how much of the substance you have. A gold ring and a gold bar have the same density, which is what makes it useful for identification.
Units, where most errors happen
The units must be consistent before you divide. Grams with cubic centimetres give g/cm³; kilograms with cubic metres give kg/m³. The conversion between them is a factor of 1000, and 1 mL is exactly 1 cm³.
| Substance | Density (g/cm³) |
|---|---|
| Air at sea level | 0.0012 |
| Ice | 0.917 |
| Water at 4 °C | 1.000 |
| Aluminium | 2.70 |
| Iron | 7.87 |
| Lead | 11.34 |
| Gold | 19.30 |
Why ice floats
Ice is less dense than liquid water, which is unusual — most substances contract on freezing. Hydrogen bonding holds water molecules in an open lattice in the solid, so the same mass occupies more volume. Lakes therefore freeze from the top down, which is the reason anything survives in them over winter.
Measuring volume by displacement
For an irregular solid, submerge it in a graduated cylinder and take the rise in level as its volume. The object must sink and must not dissolve or absorb water, or the reading is meaningless.