CONCEPTS

# What is density?

We explain what is the density and some characteristics of this property. In addition, other types of density that exist.

1. ### What is density?

The term densitye comes from the field of physics and chemistry , in which it specifically refers to the relationship between the mass of a substance (or a body) and its volume . It is therefore an intrinsic property, since it does not depend on the amount of substance considered.

Densitye, property that is usually expressed in kilograms per cubic meter (kg / m 3 ) or gram per cubic centimeter (g / cm 3 ) , varies to a greater or lesser extent depending on pressure and temperature, and also with the state changes.

Typically, gases have a lower densitye than liquids because they have less cohesive particles , and these in turn less than solids . Although there are exceptions, usually increasing the temperature decreases densityee. The densitye defined above is the absolute density ; The relative densitye is the densitye of one substance in relation to another, the apparent density is what characterizes porous materials, such as soil.

The densitye of water is 1 g / cm 3 ; that of lead , for example, is much higher: 11.35 g / cm 3 . It is precisely why in colloquial language, especially among young people, the term “dense” is used (and even “lead”) to qualify a person heavy, burdensome, or a problematic, complex situation Tilda of “dense” ( dense atmosphere, dense conversation, etc.).

1. ### Other types of density

• Population Density  In the area of ​​demography, an important concept is that of population densitye, which refers to the number of inhabitants per square kilometer. China and India are examples of countries with very high population density, while the Nordic countries and Oceania have low population density. Areas of high population density are often associated with housing problems, air pollution , insufficient public services infrastructure, among others.
• Optical density  This physical parameter constitutes the absorption of an optical element at a given wavelength per unit distance. This data is used to assess cell content , smoke quality generated by different substances, laser power, filters, etc.
• Density of electrical current.  It is the relationship that exists between the intensity of electric current that circulates through a conductor per unit of time and per unit of cross section.
• Density of magnetic flux.  Also called “magnetic induction,” it is the magnetic flux that causes an electric charge in motion for each unit of area normal to the direction of the flow.
• Bone mineral densitye In the medical field, this measure refers to the amount of minerals per unit area. It is usually expressed in g / cm 2 and is established for certain bones specifically, such as the femur or lumbar spine. A low bone mineral densitye can trigger osteoporosis, a disease in which the bones are found with a very low proportion of minerals (mainly calcium), so they become too porous and therefore fragile and brittle, thus increasing the risk of people to suffer fractures.