We explain what thermal energy is, how it is obtained and what its characteristics are. Also, what is heat energy.
What is thermal energy?
Thermal energy or caloric energy is the degree of internal energy contained in a thermodynamic system in equilibrium (a body, a set of particles, a molecule, etc.) and which is proportional to its absolute temperature.
In other words, thermal energy is what generates the internal and random movement of the particles of a body (that is, it is equivalent to kinetic energy), which increases or decreases by energy transfer, usually in the form of heat. or work.
The temperature of a system and its ability to generate work (motion, etc.) depend on its thermal energy. This is because, as with all forms of energy, can be transformed, transmitted or preserved up to a point.
This implies that thermal energy also is responsible for the states of aggregation of matter since the higher the energy levels, the greater the agitation of the constituent particles of the matter and the less possibility of them sharing a 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. Therefore, we can generally heat (that is, introduce thermal energy) a solid and bring it to the liquid state, and continue heating it to bring it to the 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 of a body or system.
- Heat. It is the transfer of internal energy from one body or system to another, as a product of a temperature difference.
- thermal energy. It is the total energy of the molecules within a body or system.
See also: Thermodynamics
Characteristics of thermal energy
As All thermodynamic systems tend to achieve thermal equilibrium with their surroundings this energy must be able to be transmitted from one body to another or from a body to the 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 the highest temperature will transfer heat to the other, by convection.
- Radiation. Energy is transferred without the need for physical contact and through electromagnetic waves. For example, the sun transmits thermal energy by radiation.
How is thermal energy obtained?
Thermal energy can be obtained in multiple ways, through different sources that deliver heat. So, for example, A heater in winter is a source of thermal energy that gives off heat and that our body absorbs to stay warm.
The heat provided by the heating comes from the electrical energy transformation in thermal energy, that is, the sources of this type of energy can be fed by other forms of energy. For example, thermal energy can be obtained from chemical reactions, especially oxidation-reduction or combustion.
When we light a bonfire, when we eat and digest food or when we mix certain acids and certain metals, we are giving rise to a chemical (or biochemical, in our body) reaction 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 humanity, since it gives us the possibility of control the temperature of our body and space that we inhabit, and guarantees our comfort or even survival in hostile climatic environments.
But at the same time, the thermal energy can lead to uncontrolled scenarios in which heat triggers combustion reactions that can produce disasters, such as fires, suffocation or unforeseen chemical reactions.
Examples of thermal energy
Some examples of thermal energy:
- The heat of the Sun, radiated into the space around it and that we receive along with its light every day.
- The heat we add to food when cooking greatly increases its thermal energy and produces chemical changes in its composition that allow us to digest it more easily.
- An on heating adds thermal energy to the environment of a room, which our body absorbs from the air, and we perceive it as heat.
- When we light a match, we trigger an exothermic reaction, that is, a reaction that increases the thermal energy of the system, at least during the time it takes for the match 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.
Continue with: Calorie
References
- “Thermal energy” in Wikipedia.
- “Thermal energy” in the Ministry of Education of Spain.
- “What is thermal energy?” at Khan Academy.
- “Thermal energy and temperature” in ICT Resources.
- “Thermal energy” in The Encyclopaedia Britannica.
