Heat is understood from the transit of energy between bodies and can be measured in calories (cal) or joules (j). The temperature is measured in degrees Celsius (ºC), Fahrenheit (ºF) or Kelvin (K) and is related to the level of agitation of molecules.
There are two concepts of thermology, an area of Physics. In it, the concept of heat represents heat energy, the ability of a body, of higher temperature, to transmit part of that energy to others, of lower temperature.
While the concept of temperature, properly speaking, represents the agitation of the molecules or atoms of a substance. The hotter, the greater the movement of atoms and molecules, the colder, the less this movement.
|Characteristics||Transit of molecular kinetic energy from the warmest to the coldest bodies.||Level of agitation of molecules and atoms in relation to the thermal state.|
|How is it to measure?||Calculation of the transit of thermal energy between bodies or systems.||Thermometers measure the temperature generated from the movement of molecules and atoms.|
|Units of measure||· lime (calorie)
· J (Joule)
|· ºC (degrees Celsius)
· ºF (degrees Fahrenheit)
· K (Kelvin)
When someone says “he is hot”, it is a mistake. No one or anything can have heat. Heat is neither possessed nor stored, what the person means refers to a thermal sensation related to the high temperature of the environment.
What is heat?
Heat means the transfer of energy from a warmer system or body to a colder one. The bodies tend to thermal balance. That is, when two or more bodies have different temperatures, that temperature tends to equalize and balance.
For this, the body with the highest temperature gives energy to the one with the lowest. In this way, there is a tendency for both bodies to reach the same temperature, entering thermal equilibrium.
Heat can spread through conduction, convection or irradiation. The first two require physical contact between the bodies, the second acts through the propagation of heat by electromagnetic waves, without requiring contact.
- Driving. When we heat the end of an iron bar, the heat is conducted and, in a short time, the entire bar will be heated.
- Convection. A pan with water on the stove creates convection zones, the warmer water rises creating a movement, heating all the liquid.
- Irradiation. The sun, even without being in contact with the Earth, radiates heat in the form of electromagnetic waves. These waves travel through space and are responsible for the temperature of the planet.
The transfer of thermal energy can be measured in Joule (J) or in calorie (lime). Each calorie represents 4.1868 Joules of energy (1cal = 4.1868J).
These same measures are found in foods and represent the amount of energy they have when we eat them.
What is temperature?
Temperature is a concept in physics that determines the (kinetic) energy of molecules. This energy has an influence on the thermal state of a body (or system).
Within a system, the higher the kinetic energy of the molecules, the higher their temperature. The same goes for the opposite: the smaller the movement of molecules, the colder the system.
For the measurement of temperature, the thermometer is generally used. Thermometers have mercury and their degree of expansion causes the level to indicate the temperature.
These values can be presented in three different scales: Celsius, Fahrenheit and Kelvin. These measurements are based on the melting point (0ºC) and boiling point (100ºC) of water. Therefore, 0ºC = 32ºF = 273K and 100ºC = 212ºF = 373K.
Heat and temperature in Physics
The area of Physics that studies the relationship between thermal energy is called Thermology.
It calculates the transit of thermal energy between systems and the temperature required to change the state of each substance.
Thermology uses the concepts of heat and temperature as the basis for several thermal relationships. For example:
- Specific heat
- Sensitive heat
- Latent heat
- Thermal capacity
- Thermal balance
- Heat flow