Density is a physical characteristic, and is a measure of mass per unit of volume of a material or substance. Density is mass divided by volume. It is a measurement of the amo
…unt of matter in a given volume of something. Density is a very important property which can be used to identify a substance. The higher an object's density, the higher its mass per unit of volume. The average density of an object equals its total mass divided by its total volume. A denser object (such as iron) will have less volume than an equal mass of some less dense substance (such as water). Water is the reference with its highest density at 3.98 °C (ρ = 1 g/cm3) and the correct SI unit of density ρ = 1000 kg/m3. 1 m3 = 1,000,000 cm3. Density Examples: Solid - water - noble gas Copper has a density of 8950 kg/m3 = 8.95 kg/dm3 = 8.95 g/cm3. Water has a density of 1000 kg/m3 = 1000 g/L = 1.000 kg/dm3 = 1.000 kg/L = 1.000 g/cm3 = 1.000 g/mL. Helium has a density of 0.1785 kg/m3 = 0.1785 g/L = 0.0001785 kg/dm3 = 0.0001785 kg/L = 0.0001785 g/cm3 = 0.0001785 g/mL. High density also means that the protons, neutrons and electrons can be tightly packed together which is controlled by the internal electric force. When a substance is heated, it usually expands because the atoms start to vibrate and take up more space, resulting in density gets lower. (MORE) 
