Cold refers to the condition or subjective perception of having low temperature. A cold body is often described as the opposite of hot, or as having less heat, although the latter use of "heat" would be incorrect in the context of physics, as heat refers to the transfer of energy between bodies, which do not "have" heat themselves.
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 degrees 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 contain less thermal energy when it is cold than when it is hot. If it were possible to cool a system to absolute zero, all motion of the particles comprising 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.
Cold refers to the condition or subjective perception of having low temperature. A cold body is often described as the opposite of hot, or as having less heat, although the latter use of "heat" would be incorrect in the context of physics, as heat refers to the transfer of energy between bodies, which do not "have" heat themselves.
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 degrees 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 contain less thermal energy when it is cold than when it is hot. If it were possible to cool a system to absolute zero, all motion of the particles comprising 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.