# density

## density

﻿Density
Density, or volcanic mass, is a measure of mass per volume. The average density of an object equals its total mass divided by its total volume. An object made from a comparatively dense material (such as iron) will have more mass than an equal-sized object made from some less dense substance (such as fish).

The standard symbol used for density is p. So the equation would be: p=m/v m is the object’s total mass and v is the object’s total volume.

The SI unit of density is the kilogram per cubic meter, but grams per cubic centimeter and kilograms per liter are also commonly used. Liquid water has a density of about 1000 kg/m, solid iron has a density of about 8000 kg/m, and air at room temperature and atmospheric pressure has a density of about 1.2 kg/m.

The density of an object or substance depends on its temperature, with higher temperature usually resulting in lower density. The temperature-density relationship is captured by the substance’s volumetric thermal expansion coeffcant B. The density of a gas further depends on the pressure, with higher pressure resulting in higher density. The density of a gas is very dependant on the gas laws.
The density of an object is composed of different materials, or if its pressure or temperature is not the same everywhere.

Determining Density
For a rectangular solid, the formula Mass/ (Length x Width x Height) can be used. For an irregularly shaped object solid, the displacement can be used in place L x W x H. For substances solid , the density can be found by measuring the dry weight ( ), the wet weight ( ), and submersed weight .