Meaning of Latent Heat

Meaning of Latent Heat

If we focus on the field of physics, heat is the energy that is transferred from one body to another, capable of generating a change of state and the dilation of these bodies. Latent, for its part, is that which is hidden or seems inactive.

According to abbreviationfinder, the notion of latent heat refers to heat that, when received by a body, does not increase its temperature, but is used to produce a change of state.

It is important to note that temperature is the physical quantity that is responsible for expressing the level of heat. In the case of latent heat, therefore, it is energy that does not increase that magnitude in the body.

It can be said that latent heat is the energy that a body or substance requires to change its state. A substance in a liquid state, for example, needs a certain latent heat to pass into a gaseous phase. In this context, latent heat can be called heat of evaporation. In a similar sense, a solid substance requires latent heat to pass into a liquid state: the heat of fusion.

As the heat does not translate into a change in temperature while the change of state is taking place, it appears to be hidden. That is why we speak of latent heat, since heat is added to the substance without changing its temperature.

The use of this concept to describe the phenomenon that is observed when a body or a substance changes state without the applied heat affecting its temperature derives from a remote time in which scientists believed that heat was a fluid substance, and the they called caloric.

This responds to a model called caloric theory, which served at the time to explain the behaviors and physical features of heat for a long time, understanding it as a fluid, which was said to permeate matter and was the cause of its heat.

When heat is applied to a substance that does not register a change of state but its temperature does increase, experts refer to sensible heat. It is worth mentioning that this is the way in which we understand heat in everyday speech, since we only attend to the variation in temperature.

With regard to sensible heat, most of the experiments carried out suggest that to affect the temperature of a given body we need to apply an amount of heat directly proportional to its mass and to the delta of temperatures that we intend to reach.

To continue with the explanation of the concept of latent heat, let’s take, for example, an experiment through which we apply heat to an ice cube; Since the latter is at a temperature below 0 ° C, where the water had to change from a liquid to a solid state in the first place for us to obtain the piece of ice, we must reach that threshold and cross it if we want to see the reverse process.

From the moment we reach 0 ° C and until the ice cube has completely melted, its temperature will not change. The reason for this interruption in the increase in heat is due to the principle stated in the first paragraphs: latent heat is not used to affect the temperature of the body, but to produce its fusion.

As expected, once the piece of ice has melted, the temperature of the water will begin to rise until it reaches the next point of change of state, which in this case is 100 ° C, where again the temperature will remain stable. until all the substance evaporates.

Latent Heat