The Physics
Factbook
An encyclopedia of scientific essays

# Density of Seawater

Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Beicher, Robert J. Physics for Scientists and Engineers. Orlando: Saunders College, 2000.
SubstanceDensity (kg/m3)
Seawater1.03x103
1030 kg/m3
"Density and Weight." Compton's Interactive Encyclopedia. Copyright © 1994, 1995, 1996, 1997 The Learning Company, Inc. "Seawater is usually some 3.5 percent heavier than fresh water because it contains about 35 pounds of salts in each 1,000 pounds of water" 1035 kg/m3
Windows to the Universe team. Density of Ocean Water. Boulder, CO: ©2000-01 University Corporation of Atmospheric Research (UCAR), ©1995-1999, 2000 The Regents of the University of Michigan. "Density of ocean water at the sea surface is about 1027 kg/m3." 1027 kg/m3
"Ocean - Density and Pressure." Encyclopedia Britannica., USA, 1965. "For the reason as stated under salinity, it is customary to report the density os seawater in equivalent to "grams per litre excess over one kilogram,"designated by the symbol σ. In this notation, the specific gravity of 1.025 is expressed as σ of 25." 1025 kg/m3
Introduction to Hydrolog. Department of Geography, Okanagan University College., 11 June 2001. "The density of seawater at the surface of the ocean varies from 1,020 to 1,029 kilograms per cubic meter." 1020–1029 kg/m3

The density of an object is the ratio of its mass to its volume. Density can also be expressed as specific gravity, which is the ratio of the density of a material to the density of water. Where the density of water in SI units is 1000 kilogram per cubic meter.

The density of seawater varies with temperature and salinity of the water. As temperature increases, density decreases. As salinity of the water increasaes, density also increases. Although the density of seawater varies at different points in the ocean, a good estimate of its density at the ocean's surface is 1025 kilogram per cubic meter. Its specific gravity is therefore 1.025.

Edward LaValley -- 2002

Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Glencoe Earth Science. Ohio: McGraw Hill, 2002: 395. "Because of salinity and temperature variations, the density of seawater ranges from about 1.02 g/cm3 to 1.03 g/cm3." 1030 kg/m3
Van Nostrand's, Scientific Encyclopedia 7th edition. Canada, 1989: 2046. "While density of pure water at 4 degrees Celsius is equal to 1, the density of seawater ranges over somewhat higher values, which vary with proximity to shores, rivers, etc., as well as with geographic location & depth. Representative average values are 1.026–1.028," 1026–1028 kg/m3
Gross, Grant, M. Oceanography 6th edition. Ohio, 1994: 51. "At 30 degrees Celsius, a change in salinity from 34 0/00 to 35 0/00 changes the density from 1.021 to 1.022." 1021–1022 kg/m3
Handbook of Chemistry and Physics 48th edition. Ohio, 1967-1968: F-3. "Density of Various Liquids
Sea Water … 1.025 g/cm3"
1025 kg/m3
Jim Manning. How do we measure the density of sea water? Woods Hole Oceanographic Institute, 2001. Since freshwater weighs about 1000 kilograms per cubic meter and seawater weighs about 1.026 times that, we say that the typical seawater density is 1026 kg/m3." 1026 kg/m3

Seawater has been the source of life It is where the first living and breathing organisms set fins on planet Earth. Most of the Earth's surface, approximately 70%, is covered with seawater. Scientists believed the Earth has been covered by water since shortly after the beginning of its existence.

Two of the most important variables in seawater are temperature and salinity (the concentration of dissolved salts). The two quantities work in conjunction to control the density of seawater. Since the composition of seawater is affected mainly by the addition of dissolved salts brought to it by the rivers, volcanic eruptions, erosion of rocks, and many other ways, the composition differs from one region to the next.

The physical properties of seawater to be quite different from those of freshwater. The presence of various salts make seawater undrinkable The total dissolved salts in seawater are approximately 34.4 g/L, some 300 times that of river water. The main dissolved constituents in seawater include sodium and chloride. Since salt ions are heavier than water molecules, seawater is denser than freshwater. The density of seawater ranges from 1020 to 1030 kg/m3 while the density of freshwater is about 1000 kg/m3. Variations in salinity also cause the freezing point of seawater to be somewhat lower than that of freshwater. (Freshwater freezes at zero degrees Celsius.) Since salt ions interfere with the formation of hydrogen bonds, seawater does not have a fixed freezing point.

Today, we have inventions that can turn seawater into freshwater, and from that we can actually drink it without being afraid that we have too much salt in your body. So drink up (freshwater).

Edwin Cartagena -- 2002