Cold refers to the condition or subjective perception of having low temperature, the opposite of hot.
A lower bound to temperature is the absolute zero, defined as 0 K on the Kelvin scale, an absolute thermodynamic temperature scale. This corresponds to −273.15 °C on the Celsius scale, −459.67 °F on the Fahrenheit scale, and 0 °R on the Rankine scale.
Since temperature relates to the thermal energy held by an object or a sample of matter, which is the kinetic energy of the random motion of the particle constituents of matter, an object will have less thermal energy when it is colder and more when it is hotter. If it were possible to cool a system to absolute zero, all motion of the particles in a sample of matter would cease and they would be at complete rest in this classical sense. The object would be described as having zero thermal energy. Microscopically in the description of quantum mechanics, however, matter still has zero-point energy even at absolute zero, because of the uncertainty principle.
Other articles related to "cold":
... rocket incident was a few minutes of post-Cold War nuclear tension that took place nearly four years after the end of the Cold War ... The 1995 incident occurred in the post-Cold War era, where many Russians were very suspicious of the United States and NATO ...
... Aluminum cranks may be cast, hot forged or cold forged ("cold" in this context means the billet from which the crank is to be made is heated to a specified temperature well below the melting point, not room ... Cold forging gives the metal additional strength, and the cranks can therefore be made lighter without increasing the risk of breakage ...
... moderately warm in the valleys and foothills, moderately cold in the lower mountains and cold in the higher elevations ... from subtropical, found on the plains, to cold in the nearby mountains ...
... has been successfully hybridized with the cold-hardy Hibiscus moscheutos and several other North American Hibiscus species, producing cold-hardy hybrids (see cold-hardy ... this hobby, which is practiced with these tropical plants worldwide, including indoors in cold climates ...
... thought to be unmyelinated C-fibres (low conduction velocity), while those responding to cold have both C-fibers and thinly myelinated A delta fibers (faster ... For cold receptors their firing rate increases during cooling and decreases during warming ... Some cold receptors also respond with a brief action potential discharge to high temperatures, i.e ...
Famous quotes containing the word cold:
“Is this a holy thing to see
In a rich and fruitful land,
Babes reduced to misery,
Fed with cold and usurous hand?”
—William Blake (17571827)
“When all is said and done, friendship is the only trustworthy fabric of the affections. So-called love is a delirious inhuman state of mind: when hot it substitutes indulgence for fair play; when cold it is cruel, but friendship is warmth in cold, firm ground in a bog.”
—Miles Franklin (18791954)
“A mans social and spiritual discipline must answer to his corporeal. He must lean on a friend who has a hard breast, as he would lie on a hard bed. He must drink cold water for his only beverage. So he must not hear sweetened and colored words, but pure and refreshing truths. He must daily bathe in truth cold as spring water, not warmed by the sympathy of friends.”
—Henry David Thoreau (18171862)