The properties of materials.

click fraud protection

study of thermal phenomena required the introduction of the concept of physicists specific heat.Despite his fickle and dependent on many factors, this value allows you to facilitate the calculations not only in the course of the experiments, but also in the practical production activities.

physical meaning of specific heat, which in SI measured in joules per kilograms-Kelvin, is the amount of heat (thermal energy) required to compound mass in one kilogram changed its temperature by one Kelvin (degrees).

The magnitude of the specific heat affects the actual temperature of the substance.Water heated to 20 ° C to 60 ° C, it has different values ​​characterizing this indicator.For the main substances in the experimental studies was calculated their specific heat.The formula was derived to determine the relationship between several variables.The mathematical expression combines multiple physical quantities.The first is a very specific heat capacity, which for ease of study taken for a constant value under standard conditions.Sometimes it is calculated for certain conditions, for example, water vapor (water heated to a temperature of 373 Kelvin or 100 ° C).This is followed by a value that indicates the amount of heat produced (gave) a substance by heating (cooling) is heated (cooled) substances, the temperature difference before and after the process.

Specific heat is important when choosing a particular substance as a building material for use in a variety of refrigeration systems and heating systems.It has long been observed that materials having the same mass, are used for heating the different quantity of heat energy.Aluminium coatings, for example to obtain uniform supply of heat from the natural solar radiation, and will heat up more strongly than the same structures made of wood or ordinary plaster.

considering concrete with a specific heat of 1000 J / kg-K, one can conclude that the heating of one kilogram of the material per kelvin require energy of 1000 J. Wood to obtain the same effect using twice more heat than thethe same mass of gas concrete.It affects not only the microclimatic comfort of the premises, but also on the different rates of temperature elongation designs.

particular interest in terms of the heat exchange process is ordinary water.For example, it can be clearly traced, that the indicator "specific heat capacity" of each substance plays a huge influence his physical state.Continuing the example of water, revealed an interesting pattern.At 0 ° C in the liquid state it has a specific heat of 4.218, and increasing the temperature to 40 ° C has 4,178 kJ / (kg * K).But the ice temperature at step 0 ° C heat capacity drops to the level of 2.11 kJ / (kg * K).

Water is a liquid with the highest specific heat.For the next jump by one degree, it absorbs or gives a large volume of heat than any other substance.This water is used as needed to provide an artificial heat.

For the convenience of calculation of the specific heat table except the column with the calculated figures for one kilogram, has an additional column with the expressions of the characteristics of one liter (or dm3) of the substance.Using the data tables, engineers and designers make the selection of the most appropriate materials for the realization of their plans and ideas.With the advent of new materials with unique properties it has expanded the range to choose from, but even a simple and accessible material is sometimes able to make them compete.