Specific heat of fusion is very interesting

It is a well-known fact that a substance can be in one of the states - gaseous, liquid, solid. And can move from one to another. The simplest example - a piece of ice melts, turns into liquid and then into steam. In all this process of transformation of a solid into a vapor, the melting stage is very interesting and one of its parameters is the specific heat of fusion.

Our experience shows that any substance can be melted. The whole history of civilization testifies to this. The discovery of the melting of matter was one of the greatest inventions in the development of mankind. But melting is not an easy process. At its carrying out there are many questions, and one of them about how much coal (peat, firewood, gas) is needed to melt a piece of iron or copper. And here again we have to turn to the concept of "specific heat of fusion".

If we recall how melting is going on, we can distinguish several stages. Take lead as an example. At the first stage, lead is heated, the temperature rises to 327 degrees Celsius (melting point). After melting has begun, for a long time nothing happens.

The temperature of the lead, despite the heat supplied to it, remains constant and holds until the whole process is completed. And only after this, with continued heating, the temperature begins to rise again. From the observed picture, some conclusions follow. For a solid, all molecules are in a certain order and are rigidly bound to neighboring molecules.

In order for them to move freely to another place, links with neighboring molecules must be broken, which is what happens in the melting process. For this, the body needs to transfer a certain heat rate, called heat of fusion. For each substance, a different amount of heat is required. The reason is due to such a property of the substance as the specific heat of melting, which is defined as the amount of heat spent on melting one kilogram of matter. The unit of measurement is Joule / kilogram.

As already mentioned, for each material this value is different. The specific heat of lead melting differs from the same value for ice. And here comes a very curious moment. The specific heat of melting of steel averages 85 kJ / kg, while for water (ice) the same parameter averages 335 kJ / kg. At ice, the high value of this parameter can be considered a great gift from nature.

Because of this, all snow, ice does not melt instantly, but everything happens for a long time. Otherwise, the snow would melt very quickly, and the floods would be more water and destructive. In addition, such unique properties of water contribute to the stabilization of the climate on the planet.

There are tables with data on the specific heat of fusion of individual materials. Knowing this value, you calculate how much heat you need to melt the material, and determine how much fuel you need to carry out the melting. If the body is heated to the melting point, then the heat is only needed for melting, and if its temperature is below the melting point, then the heat is needed to heat the material to the melting temperature.

Such calculations are extremely useful in the industry for calculating production costs.

By the way, when the molten substance cools, the process - crystallization - is reversed. In this case, when the substance cools, the broken bonds between the molecules are restored and heat is released.

Considering the process of melting of matter and the phenomena occurring at the same time, such a concept as the specific heat of melting was defined. Comparison of this indicator for different substances is made, it is determined how the high value of this parameter in ice has a beneficial effect on the climate of the planet.