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.
Famous quotes containing the word cold:
“For half a mile from the shore it was one mass of white breakers, which, with the wind, made such a din that we could hardly hear ourselves speak.... This was the stormiest sea that we witnessed,more tumultuous, my companion affirmed, than the rapids of Niagara, and, of course, on a far greater scale. It was the ocean in a gale, a clear, cold day, with only one sail in sight, which labored much, as if it were anxiously seeking a harbor.... It was the roaring sea, thalassa exeessa.”
—Henry David Thoreau (18171862)
“My salad days,
When I was green in judgment, cold in blood,
To say as I said then!”
—William Shakespeare (15641616)
“If her horny feet protrude, they come
To show how cold she is, and dumb.”
—Wallace Stevens (18791955)