# Density

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The term density is the mass of a substance per unit volume. The symbol most often used for density is ρ, and sometimes the letter D can also be used. Mathematically, density is defined as mass divided by volume:

ρ = m/V

Where m = mass of the substance, V = volume.

Density is measured in g/cm3 or kg/m3.

The density of a substance is influenced by a variety of factors, such as pressure or temperature. They have little influence for most solid materials, but there's a significant effect on the density of solids and liquids.

Density is calculated depending on the type of material:

• Homogeneous materials: The density at all regions of a homogeneous object equals its total mass divided by its total volume.
• Heterogeneous materials: The density varies between different regions of the object. The density of heterogeneous materials is calculated by determining the densities of many small volumes around various locations of the said material.
• Non-compact materials: Materials such as flakes, pellets, granules or powders contain voids, such as air, water or other fluids. The density of such materials is determined by multiple methods, such as pycnometer method or mathematical expressions for various geometric shapes.

## List of densities

### Density of solids

Material Density (kg/m3)
Aerographite 0.2
Styrofoam 75
Magnesium 1,740
Iron 7,870