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Water’s lower density in its solid form is due to the way hydrogen bonds are oriented as it freezes: the water molecules are pushed farther apart compared to liquid water. With most other liquids, solidification when the temperature drops includes the lowering of kinetic energy between molecules, allowing them to pack even more tightly than in liquid form and giving the solid a greater density than the liquid.

The lower density of ice, illustrated and pictured in [link] , an anomaly, causes it to float at the surface of liquid water, such as in an iceberg or in the ice cubes in a glass of ice water. In lakes and ponds, ice will form on the surface of the water creating an insulating barrier that protects the animals and plant life in the pond from freezing. Without this layer of insulating ice, plants and animals living in the pond would freeze in the solid block of ice and could not survive. The detrimental effect of freezing on living organisms is caused by the expansion of ice relative to liquid water. The ice crystals that form upon freezing rupture the delicate membranes essential for the function of living cells, irreversibly damaging them. Cells can only survive freezing if the water in them is temporarily replaced by another liquid like glycerol.

Ice floes float on ocean water near a mountain range that rises out of the water.
Hydrogen bonding makes ice less dense than liquid water. The (a) lattice structure of ice makes it less dense than the freely flowing molecules of liquid water, enabling it to (b) float on water. (credit a: modification of work by Jane Whitney, image created using Visual Molecular Dynamics (VMD) software W. Humphrey W., A. Dalke, and K. Schulten, “VMD—Visual Molecular Dynamics,” Journal of Molecular Graphics 14 (1996): 33-38. ; credit b: modification of work by Carlos Ponte)

Click here to see a 3-D animation of the structure of an ice lattice. (Image credit: Jane Whitney. Image created using Visual Molecular Dynamics VMD software. W. Humphrey W., A. Dalke, and K. Schulten, “VMD—Visual Molecular Dynamics,” Journal of Molecular Graphics 14 (1996): 33-38. )

Water’s high heat capacity

Water’s high heat capacity is a property caused by hydrogen bonding among water molecules. Water has the highest specific heat capacity    of any liquids. Specific heat is defined as the amount of heat one gram of a substance must absorb or lose to change its temperature by one degree Celsius. For water, this amount is one calorie    . It therefore takes water a long time to heat and long time to cool. In fact, the specific heat capacity of water is about five times more than that of sand. This explains why the land cools faster than the sea. Due to its high heat capacity, water is used by warm blooded animals to more evenly disperse heat in their bodies: it acts in a similar manner to a car’s cooling system, transporting heat from warm places to cool places, causing the body to maintain a more even temperature.

Water’s heat of vaporization

Water also has a high heat of vaporization , the amount of energy required to change one gram of a liquid substance to a gas. A considerable amount of heat energy (586 cal) is required to accomplish this change in water. This process occurs on the surface of water. As liquid water heats up, hydrogen bonding makes it difficult to separate the liquid water molecules from each other, which is required for it to enter its gaseous phase (steam). As a result, water acts as a heat sink or heat reservoir and requires much more heat to boil than does a liquid such as ethanol (grain alcohol), whose hydrogen bonding with other ethanol molecules is weaker than water’s hydrogen bonding. Eventually, as water reaches its boiling point of 100° Celsius (212° Fahrenheit), the heat is able to break the hydrogen bonds between the water molecules, and the kinetic energy (motion) between the water molecules allows them to escape from the liquid as a gas. Even when below its boiling point, water’s individual molecules acquire enough energy from other water molecules such that some surface water molecules can escape and vaporize: this process is known as evaporation    .

Questions & Answers

what are some functions of the DNA
Seth Reply
What is biodiversity
Chati Reply
the diversity of plants and animals life in a particula habitat
Harry
Biodiversity is the variety of organisms in their common groups
Osei
what is glycolisis
David Reply
glycolisis is the breakdown of glucose
Yazi
the answer is incomplete the breakdown of glucose to what
David
what is biodiversity?
Hope Reply
What is biodiversity
Chati
what is taxonomy
Patience Reply
Taxonomy is a branch of biology that deals with the description, identification, nomenclature, and classification of organisms
Farco
what is nomenclature
John
nomenclature is the scientific naming of organisms
Bigenis
state the structural differences between the termites
Massa
what causes the DNA results of an offspring
venius Reply
how are proteins digested?
Trox Reply
how are proteins digested
Kaka
guys what is locomotion?
Misheal Reply
what is anatomy
Mohamed Reply
no idea
Benard
Anatomy is the branch of science that deals with the study of internal and external structures of an organism
Bigenis
Anatomy is the branch of science that deals with the study of the internal structure of an organism
Nana
what is locomotion?
Misheal
no idea
John
Locomotion may simply mean the movement of an organism from one point to another without permanent displacement of the organidm it'self
Bigenis
simply, its the ability to move
MissMeriiit
Thanks guys
Misheal
I have gotten it
Dickens
locomotion as an art student is the ability to move from on place to another
John
muscles that are concerned with locomotion
John
Anatomy deals with the study of internal structures of an organism
Osei
The ability of cells or organisms to move and propel itself from place to place. supplement. locomotion in biology pertains to the various movements of organisms (single-celled or multicellular organisms) to propel themselves from one place to another.
garnhial
Anatomy is the branch of biology concerned with structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structure organization of living things - human anatomy is one of the essential basic sciences that are applied in medicine
garnhial
what is multicellular organisms
Massa
multicellular organisms these are living things which have more than one cell
John
what are the theory if cells
Julius Reply
What's the function of epiglottis
Ugo Reply
What Is The Other Name For Intestinal Juice?
Justin Reply
what is the largestest planet of the universe
rick Reply
what are the types of cell
Bernard Reply
prokaryotic and eukaryotic
Yazi
prokaryotic cell and eukaryotic cell
Grace
what is the protein found in the blood?
Tobias Reply
globin
Joelia
Globin
globulins
EZRA
globulins
SASMITA
globulins
Grace
globulin
David

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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