The New Complete Book of Food
pressure of air above the surface, the liquid will boil and some of its molecules will vaporize
to a gas that floats off the surface as the liquid evaporates.
At sea level, plain water boils at 212°F (100°C), the temperature at which its molecules
have absorbed enough energy to begin to escape from the surface as steam. If you add salt
to the water before it starts to boil, the water molecules will need to pick up extra energy in
order to overcome the greater attractive forces between the salt and water molecules. Since
the energy comes from heat, adding salt raises the boiling point of the water. Salted water
boils at a higher temperature than plain water does. That is why pasta, rice, and other foods
cook more quickly in boiling salted water than in plain boiling water.How Other Kinds of Processing Affect This Food
Freezing. Water is the only compound that expands when it freezes. A water molecule is
shaped roughly like an open triangle, with an oxygen atom at the center and a hydrogen atom
at the end of either arm. When water is frozen, its molecules move more slowly, and each
hydrogen atom forms a temporary bond to the oxygen atom on a nearby water molecule. The
phenomenon, known as hydrogen bonding, creates a rigid structure in which the molecules
stretch out rather than pack closely together, as normally happens when a substance is cooled.
An ounce of frozen water (ice) takes up more room than an ounce of liquid water.
“Softening.” Home water softeners that filter out “hard” calcium carbonate and replace it
with sodium may increase the sodium content of tap water by as much as 100 mg per quart.Medical Uses and/or Benefits
Maintaining body functions. The body uses water in and around body cells and tissues to
regulate body temperature; create blood, lymph, and body secretions; digest food; dissolve
and circulate nutrients; eliminate waste; and lubricate joints.
Protection against dental cavities. Fluoridated drinking water provides fluoride ions that are
incorporated into the crystalline structure of dental enamel, hardening the tooth surface and
making it more resistant to bacteria such as Mutans streptococcus, a type of bacteria that live
in sticky dental plaque, digesting sugars and excreting acidic material that eats away at the
tooth. To obtain the most protection, the American Dental Association says children should
drink fluoridated water from birth through the eruption of their permanent teeth, around
ages 12 to 13.
Relief from constipation. Water bulks up stool and moves it more quickly and easily through
your body; a glass of warm water first thing in the morning stimulates gastric juices and
exerts a mild laxative effect.
Relief from stuffed nose caused by cold or seasonal (mold, pollen) allergy. Warm beverages
loosen mucous, making it easier to clear your nasal passages.