What is Temperature (definition and Concept)

temperature is one physical magnitude that indicates the internal energy of a body, an object or the environment in general, measured by a thermometer.

Said internal energy is expressed in terms of heat and cold, the former being associated with a higher temperature, while cold is associated with a lower temperature.

The units of measurement for temperature are degrees. Celsius (ºC), degrees Fahrenheit (ºF) and degrees Kelvin (K). Absolute zero (0 K) corresponds to -273.15 ºC.

temperature in physics

In physics, temperature refers to a magnitude used to measure the kinetic energy of a thermodynamic system, which is generated by the movements of the particles that are part of the system. The greater the movement, the temperature increases, while the less movement the temperature tends to decrease.

See also: Kinetic energy and Magnitude.

Difference Between Heat and Temperature

When an object is heated we know that its temperature increases and for this reason these concepts sometimes tend to be confused. However, while heat and temperature are related to each other, they are two different variables.

  • Heat is the total energy of the motion of particles in a body.while temperature is the magnitude that measures that energy.
  • Heat depends on the speed of the particles, their number, their size and their type. The temperature does not depend on those variables.

As an example, two containers of water, one large and one small, are boiled. The boiling point is 100 degrees, therefore both containers will have the same temperature. But in the larger container there is more water, and therefore, there is more movement of particles and more heat than in the smaller container.

See also Heat.

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Melting and boiling temperature

When we refer to the melting point we are talking about the temperature at which matter is in a solid state and then transforms into a liquid state.

In the same way, once matter in a liquid state continues to increase in temperature, it can reach its boiling point, that is, it goes from a liquid state to a gaseous state.

The melting point of water is 0 °C, and its boiling point is 100 °C, so while it is below 0 °C it is in a solid state, in the form of ice, and when it is between 1 °C and 99 °C it is liquid.

See also: Gaseous state and Intensive and extensive properties of matter.

atmospheric temperature

Atmospheric temperature is the level of heat in the air at a given geographical point and is the main variable to consider to define climatic types:

  • macrothermal: high temperatures.
  • mesothermic: temperate climates.
  • Microthermal: low temperatures.

In turn, atmospheric temperature has three categories:

  • Maximum temperature: as its name indicates, it is the highest temperature that the air can register in a period of a day, a month or a year in a given area.
  • Minimum temperature: is the lowest temperature recorded by the air in a day, month or year in a specific geographical area.
  • Medium temperature: is the average of the maximum and minimum temperatures of a place. With these data, monthly, annual or longer average temperatures can be obtained, which allows a more extensive climatic record to be made.

Room temperature

The room temperature is the one that is optimal to stay in a closed place and in balance between cold and heat. Thus, it is considered that a temperature ranging between 15ºC and 23ºC is the most acceptable for humans.

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However, the ambient temperature is not considered a scientific variable, but only a range commonly used to regulate the heat levels of a given space.

Body temperature

Body temperature refers to the increase or decrease of heat in an organism. And to control temperature, each organism has its own thermoregulatory mechanisms, which are biological processes that are activated to increase or decrease temperature, and thus adapt to environmental conditions.

In humans, the normal body temperature is 37 degrees. To maintain it, the body resorts to several thermoregulatory mechanisms, among which vasodilation (decrease in skin temperature) stands out to increase or maintain heat and sweating to lower it.

An increase in temperature indicates the presence of a fever, which acts as the body’s response to an infection or health condition. Whereas a decrease in normal body temperature may indicate hypothermia, which can be caused by very cold ambient temperatures or as a symptom of illness.

ignition temperature

It is the minimum temperature required for a substance or material to start burning when it is close to a heat source. The time that the generated flame can be kept lit once the source is removed is also considered.

To define the ignition temperature, it is required that the heat source has a higher temperature than that of the material that is going to burn.

Softwood, for example, has an ignition temperature that ranges between 310ºC and 350ºC. While gasoline begins to burn at 456ºC.