Heat vs. Temperature

By Jaxson

Main Difference

The main difference between Heat and Temperature is that the Heat is a energy transfer process, or its amount (and direction), that is associated with a temperature difference and Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold

  • Heat

    In thermodynamics, heat is energy in transfer to or from a thermodynamic system, by mechanisms other than thermodynamic work or transfer of matter. The mechanisms include conduction, through direct contact of immobile bodies, or through a wall or barrier that is impermeable to matter; or radiation between separated bodies; or friction due to isochoric mechanical or electrical or magnetic or gravitational work done by the surroundings on the system of interest, such as Joule heating due to an electric current driven through the system of interest by an external system, or through a magnetic stirrer. When there is a suitable path between two systems with different temperatures, heat transfer occurs necessarily, immediately, and spontaneously from the hotter to the colder system. Thermal conduction occurs by the stochastic (random) motion of microscopic particles (such as atoms or molecules). In contrast, thermodynamic work is defined by mechanisms that act macroscopically and directly on the system’s whole-body state variables; for example, change of the system’s volume through a piston’s motion with externally measurable force; or change of the system’s internal electric polarization through an externally measurable change in electric field. The definition of heat transfer does not require that the process be in any sense smooth. For example, a bolt of lightning may transfer heat to a body.

    Convective circulation allows one body to heat another, through an intermediate circulating fluid that carries energy from a boundary of one to a boundary of the other; the actual heat transfer is by conduction and radiation between the fluid and the respective bodies. Convective circulation, though spontaneous, does not necessarily and immediately occur simply because of some slight temperature difference; for it to occur in a given arrangement of systems, there is a threshold that must be crossed.

    Like thermodynamic work, heat transfer is a process involving more than one system, not a property of any one system. In thermodynamics, energy transferred as heat (a process function) contributes to change in the system’s cardinal energy variable of state, for example its internal energy, or for example its enthalpy. This is to be distinguished from the ordinary language conception of heat as a property of an isolated system.

    Although heat flows spontaneously from a hotter body to a cooler one, it is possible to construct a heat pump which expends work to transfer energy from a colder body to a hotter body. In contrast, a heat engine reduces an existing temperature difference to supply work to another system. Another thermodynamic type of heat transfer device is an active heat spreader, which expends work to speed up transfer of energy to colder surroundings from a hotter body, for example a computer component.The amount of heat transferred in any process can be defined as the total amount of transferred energy excluding any macroscopic work that was done and any energy contained in matter transferred. For the precise definition of heat, it is necessary that it occur by a path that does not include transfer of matter. As an amount of energy (being transferred), the SI unit of heat is the joule (J). The conventional symbol used to represent the amount of heat transferred in a thermodynamic process is Q. Heat is measured by its effect on the states of interacting bodies, for example, by the amount of ice melted or a change in temperature. The quantification of heat via the temperature change of a body is called calorimetry.

  • Temperature

    Temperature is a physical quantity expressing hot and cold. It is measured with a thermometer calibrated in one or more temperature scales. The most commonly used scales are the Celsius scale (formerly called centigrade) (denoted °C), Fahrenheit scale (denoted °F), and Kelvin scale (denoted K). The kelvin (spelled with a lower-case k) is the unit of temperature in the International System of Units (abbreviated SI), in which temperature is one of the seven fundamental base quantities. The Kelvin scale is widely used in science and technology.

    Theoretically, the coldest a system can be is when its temperature is absolute zero, at which point the thermal motion in matter would be zero. However, an actual physical system or object can never attain a temperature of absolute zero. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, and −459.67 °F on the Fahrenheit scale.

    For an ideal gas, temperature is proportional to the average kinetic energy of the random microscopic motions of the constituent microscopic particles.

    Temperature is important in all fields of natural science, including physics, chemistry, Earth science, medicine, and biology, as well as most aspects of daily life.

  • Heat (noun)

    Thermal energy.

    “This furnace puts out 5000 BTUs of heat.”

    “That engine is really throwing off some heat.”

    “Removal of heat from the liquid caused it to turn into a solid.”

  • Heat (noun)

    The condition or quality of being hot.

    “Stay out of the heat of the sun!”

  • Heat (noun)

    An attribute of a spice that causes a burning sensation in the mouth.

    “The chili sauce gave the dish heat.”

  • Heat (noun)

    A period of intensity, particularly of emotion.


    “It’s easy to make bad decisions in the heat of the moment.”

  • Heat (noun)

    An undesirable amount of attention.

    “The heat from her family after her DUI arrest was unbearable.”

  • Heat (noun)

    The police.

    “The heat! Scram!”

  • Heat (noun)

    One or more firearms.

  • Heat (noun)

    A fastball.

    “The catcher called for the heat, high and tight.”

  • Heat (noun)

    A condition where a mammal is aroused sexually or where it is especially fertile and therefore eager to mate.

    “The male canines were attracted by the female in heat.”

  • Heat (noun)

    A preliminary race, used to determine the participants in a final race

    “The runner had high hopes, but was out of contention after the first heat.”

  • Heat (noun)

    One cycle of bringing metal to maximum temperature and working it until it is too cool to work further.

    “I can make a scroll like that in a single heat.”

  • Heat (noun)

    A hot spell.

    “The children stayed indoors during this year’s summer heat.”

  • Heat (noun)

    Heating system; a system that raises the temperature of a room or building.

    “I’m freezing; could you turn on the heat?”

  • Heat (noun)

    The output of a heating system.

    “During the power outage we had no heat because the controls are electric.”

    “Older folks like more heat than the young.”

  • Heat (noun)

    In omegaverse fan fiction, a cyclical period in which alphas and omegas experience an intense, sometimes irresistible biological urge to mate.

  • Heat (verb)

    To cause an increase in temperature of (an object or space); to cause to become hot often with “up”.

    “I’ll heat up the water.”

  • Heat (verb)

    To become hotter.

    “There’s a pot of soup heating on the stove.”

  • Heat (verb)

    To excite or make hot by action or emotion; to make feverish.

  • Heat (verb)

    To excite ardour in; to rouse to action; to excite to excess; to inflame, as the passions.

  • Heat (verb)

    To arouse, to excite (sexually).

    “The massage heated her up.”

  • Temperature (noun)

    The state or condition of being tempered or moderated.

  • Temperature (noun)

    The balance of humours in the body, or one’s character or outlook as considered determined from this; temperament.

  • Temperature (noun)

    A measure of cold or heat, often measurable with a thermometer.

    “The boiling temperature of pure water is 100 degrees Celsius.”

  • Temperature (noun)

    An elevated body temperature, as present in fever and many illnesses.

    “You have a temperature; I think you should stay home today. You’re sick.”

  • Temperature (noun)

    The temperature(1) of the immediate environment.

    “The temperature dropped nearly 20 degrees; it went from hot to cold.”

  • Temperature (noun)

    A property of macroscopic amounts of matter that serves to gauge the average intensity of the random actual motions of the individually mobile particulate constituents. [http://arxiv.org/pdf/physics/0004055]


Leave a Comment