thermal energy

Physical

2022

We explain what thermal energy is, how it is obtained and what its characteristics are. Also, what is caloric energy.

The many uses of heat energy include protecting us from the cold and cooking food.

What is thermical energy?

Thermal energy or heat energy is the degree of Energy internal contained in a thermodynamic system in equilibrium (a body, a set of particles, a molecule, etc.) and that is proportional to its temperature absolute.

In other words, thermal energy is what generates the movement internal and random particles of a body (that is, it is equivalent to the Kinetic energy), which increases or decreases by energy transfer, usually in the form of heat or from job.

The temperature of a system and its ability to generate work (movement, etc.) depends on its thermal energy. This is because, as with all forms of energy, it can be transformed, transmitted, or conserved to some degree.

This implies that thermal energy is also responsible for the states of matter aggregation, since at higher energy levels, greater agitation of the constituent particles of the matter and less chance of sharing limited space.

The particles of a liquid are more energetic than those of a solid, and those of a gas much more than those of a liquid. For this reason, we can generally heat (that is, introduce thermal energy) a solid and take it to the liquid state, and continue heating it to bring it to a gaseous state.

The loss or gain of thermal energy is what defines the heating or cooling of a body or a system. However, the following concepts should not be confused:

  • Temperature. It is the average kinetic energy of the particles in a body or system.
  • Heat. It is the transfer of internal energy from one body or system to another, as a product of a difference in temperature.
  • Thermal energy. It is the total energy of the molecules within a body or system.

Characteristics of thermal energy

Thermal energy can be transmitted from one system to another.

As all thermodynamic systems tend to thermal equilibrium with its environment, this energy must be able to be transmitted from one body to another or from one body to another. environment, and it does so through three essential mechanisms:

  • Driving. The transfer of energy occurs through contact between bodies, without exchange of matter.
  • Convection. The transfer of energy occurs through the movement of a fluid (liquids or gases). If, for example, two fluids are mixed, the one with a higher temperature will transfer heat to the other, by convection.
  • Radiation. Energy is transferred without the need for physical contact and by means of electromagnetic waves. For example, the sun transmits thermal energy by radiation.

How is thermal energy obtained?

A hot drink comforts us because it introduces thermal energy into our system.

Thermal energy can be obtained in multiple ways, through different sources that deliver heat. Thus, for example, heating in winter is a source of thermal energy that gives up heat and that our body absorbs to keep warm.

The heat provided by the heating comes from the transformation of electric power in thermal energy, that is, sources of this type of energy can be powered by other forms of energy. For example, thermal energy can be obtained from chemical reactions, especially those of oxide-reduction or combustion.

When we light a fire, when we feed and digest food, or when we mix certain acids and certain metals, we are giving rise to a chemical reaction (or biochemistry, in our body) that allows us to increase our internal energy and, therefore, our thermal energy.

Advantages and disadvantages of thermal energy

The management of thermal energy is a great advantage for the humanity, since it gives us the possibility of controlling the temperature of our body and the space we inhabit, and it guarantees comfort or even survival in hostile climatic environments.

But at the same time, thermal energy can lead to uncontrolled scenarios, in which heat triggers combustion reactions that can produce disasterssuch as fires, suffocations, or unforeseen chemical reactions.

Examples of thermal energy

Heating adds heat energy to the air in a room.

Some examples of thermal energy:

  • The heat of the Sun, irradiated to the space around him and that we receive together with his light every day.
  • The heat we add to food when we cook greatly increases its thermal energy and produces chemical changes in its composition that allow us to digest it more easily.
  • A heater on adds thermal energy to the environment of a room, and that our body absorbs from the air, and we perceive it as heat.
  • When we light a match, we fire a exothermic reaction, that is, a reaction that increases the thermal energy of the system, at least during the weather it takes time for phosphorus to be consumed.
  • Some physical phenomena that generate heat, such as friction, increase the thermal energy of a system.

Thermal energy and heat energy

In general terms, we speak of thermal and caloric energy without further distinction, since both terms are basically synonyms.

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