# Mass Density

## Definition - What does Mass Density mean?

Mass density is a quantitative expression of the amount of mass contained per unit volume. The standard unit is kilograms per meter cubed (kg/m3).

The symbol most often used for density is: (the Greek letter rho).

Mass density represents the mass (or number of particles) per unit volume of a substance, material or object. Most substances (especially gases) increase in density as their pressure increases or as their temperature decreases.

Mass density can help to predict chances of corrosion of substances. Measuring mass density can help to predict a material's inherent defects which can ultimately cause different forms of corrosion.

Mass density is also known as density.

## Corrosionpedia explains Mass Density

The mass density of a material is defined as its mass per unit volume. Density is often understood as an indication of how heavy a substance is. Therefore, mass density is the measure of a material's compactness. The higher the density, the tighter the particles are packed inside the substance.

The mass density of a material varies with temperature and pressure. This variation is typically small for solids and liquids but much greater for gases. Increasing the temperature of a substance (with a few exceptions) decreases its density by increasing its volume.

Density is a fundamental physical property of matter constant at a given temperature. It is commonly used as a means of categorizing and identifying different materials. In addition, a thorough understanding of the concept of density is critical for building ships and lighter-than-air crafts such as hot air balloons.

Different materials usually have different densities, so density is an important concept regarding buoyancy, purity and packaging. For example, the nature of steel depends on its content, which results in varying densities. In most cases, the denser the steel, the harder it is.