Search results
Results from the WOW.Com Content Network
The density at all points of a homogeneous object equals its total mass divided by its total volume. The mass is normally measured with a scale or balance; the volume may be measured directly (from the geometry of the object) or by the displacement
A density meter does not measure the specific gravity of a sample directly. However, the specific gravity can be inferred from a density meter. The specific gravity is defined as the density of a sample compared to the density of a reference. The reference density is typically of that of water. The specific gravity is found by the following ...
The density of quartz is around 2.65 g/cm 3 but the (dry) bulk density of a mineral soil is normally about half that density, between 1.0 and 1.6 g/cm 3. In contrast, soils rich in soil organic carbon and some friable clays tend to have lower bulk densities ( <1.0 g/cm 3 ) due to a combination of the low-density of the organic materials ...
Specific gravity for solids and liquids is nearly always measured with respect to water at its densest (at 4 °C or 39.2 °F); for gases, the reference is air at room temperature (20 °C or 68 °F). The term "relative density" (abbreviated r.d. or RD) is preferred in SI, whereas the term "specific gravity" is gradually being abandoned. [3]
Sometimes specific volume is expressed in terms of the number of cubic centimeters occupied by one gram of a substance. In this case, the unit is the centimeter cubed per gram (cm 3 /g or cm 3 ·g −1). To convert m 3 /kg to cm 3 /g, multiply by 1000; conversely, multiply by 0.001. Specific volume is inversely proportional to density.
For example, the mass of a sample is an extensive quantity; it depends on the amount of substance. The related intensive quantity is the density which is independent of the amount. The density of water is approximately 1g/mL whether you consider a drop of water or a swimming pool, but the mass is different in the two cases.
A special type of area density is called column density (also columnar mass density or simply column density), denoted ρ A or σ. It is the mass of substance per unit area integrated along a path; [ 1 ] It is obtained integrating volumetric density ρ {\displaystyle \rho } over a column: [ 2 ] σ = ∫ ρ d s . {\displaystyle \sigma =\int \rho ...
Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans , but sometimes to other living organisms too. It is a key geographical term.