Density

From Sciencemadness Wiki
Revision as of 21:21, 12 October 2015 by Mabus (Talk | contribs) (Common densities)

Jump to: navigation, search

The term density is the mass of a substance per unit volume. The symbol most often used for density is ρ, and sometimes the letter D can also be used. Mathematically, density is defined as mass divided by volume:

ρ = m/V

Where m = mass of the substance, V = volume.

Density is measured in g/cm3 or kg/m3.

The density of a substance is influenced by a variety of factors, such as pressure or temperature. They have little influence for most solid materials, but there's a significant effect on the density of solids and liquids.

Density is calculated depending on the type of material:

  • Homogeneous materials: The density at all regions of a homogeneous object equals its total mass divided by its total volume.
  • Heterogeneous materials: The density varies between different regions of the object. The density of heterogeneous materials is calculated by determining the densities of many small volumes around various locations of the said material.
  • Non-compact materials: Materials such as flakes, pellets, granules or powders contain voids, such as air, water or other fluids. The density of such materials is determined by multiple methods, such as pycnometer method or mathematical expressions for various geometric shapes.

List of densities

Common densities

Material Density (kg/m3) Notes
Hydrogen 0.08988 g/L At 0 °C and 101.325 kPa
Helium 0.1786 At 0 °C and 101.325 kPa
Aerographite 0.2 The air inside is excluded
Metallic microlattice 0.9 Idem
Aerogel 1.0 Idem
Air 1.2 Standard conditions
Tungsten hexafluoride (gas) 12.4 Standard conditions
Liquid hydrogen 70 At –255 °C
Styrofoam 75 Average type of styrofoam
Slush hydrogen 85 At -259 °C
Solid hydrogen 86 At <−259.14 °C
Cork 240 Average type of cork
Pine 373
Lithium 535
Wood 700 Seasoned, typical
Oak 710
Potassium 860
Ice 916.7 At 0 °C
Sodium 970
Water 1,000 At 4 °C
Sea water 1,030
Nylon 1,150
Plastics 1,175 Approx. for PP, PETE and PVC
Glycerol 1,261 Standard conditions
Tetrachloroethene 1,622 Standard conditions
Fuming nitric acid 1,500
Calcium 1,550
Magnesium 1,740
Concentrated sulfuric acid 1,840
Beryllium 1,850
Sulfur (gamma) 1,920
Sulfur (beta) 1,960
Sulfur (alfa) 2,070
Silicon 2,330
Concrete 2,400
Aluminium 2,700
Bromine 3,102.8 Standard conditions
Diiodomethane 3,325
Diamond 3,500
Iodoform 4,008
Carbon tetraiodide 4,320
Titanium 4,540
Tungsten hexafluoride (solid) 4,560 At −9 °C
Selenium 4,800
Iodine 4,933
Germanium 5,323
Vanadium 6,100
Tellurium 6,240
Antimony 6,690
Zinc 7,000
Chromium 7,200
Tin 7,310
Manganese 7,325
Iron 7,780
Niobium 8,570
Brass 8,600
Cadmium 8,650
Cobalt 8,900
Nickel 8,900
Copper 8,940
Bismuth 9,750
Molybdenum 10,220
Silver 10,500
Technertium 11,000
Lead 11,340
Thorium 11,700
Palladium 12,023
Rhodium 12,410
Ruthenium 12,450
Mercury 13,546
Tantalum 16,600
Uranium 18,900
Tungsten 19,250
Gold 19,320
Plutonium 19,840
Rhenium 21,020
Platinum 21,450
Iridium 22,420
Osmium 22,570

Density of materials at different temperatures

Water

Temperature Density (kg/m3)
+100 958.4
+80 971.8
+60 983.2
+40 992.2
+30 995.6502
+25 997.0479
+22 997.7735
+20 998.2071
+15 999.1026
+10 999.7026
+4 999.9720
0 999.8395
-10 998.117
-20 993.547
-30 983.854

The values below 0 °C refer to supercooled water.

References