Energy transformation - Thermal energy

Thermal energy (heat energy) is one of the seven main form of the energy.
This is the total kinetic energy of atoms and molecules that are constantly in motion. Thermal energy causes faster moving that breaks bonds between molecules.

Even the most coldest places in the Earth or in the Space has very small but measurable heat energy.

It's important to remember that the heat and temperature are different things. Heat is not a temperature.

Temperature is a value, number related to the average kinetic energy. The absolutely temperature is measured in Kelvin degree. The most famous scales for temperature measurement are Fahrenheit (F) and Celsius (C).
Heat is energy and it is measure in Joule.

To understand the difference between heat and temperature:
If you put the iron nail into the fire it will became hot and hot because the temperature of the nail is raising. So many of people think is right to say the nail is hot, because there is a lot of heat in it.
It looks reasonable, but the right thing is to say that there is a lot of energy in the nail (because of the raising temperature).

If you try to touch the hot nail you will be burnt. Why? Because when you touch the nail the energy of the nail is transfer to you hand.

Transfer of thermal energy
Thermal energy is always transferring from a place with high temperature to a place with low temperature. So we can say that the direction of the thermal energy transferring is from warmer place to a colder one.

The main ways for transfer of thermal energy are:
  • conduction
  • convection
  • radiation

Conduction - when we have a direct contact between at least two objects with a different temperature. The warmer objects transfer energy to the colder object and because of that it occur: the temperature of the colder object became to raise when at the same time the temperature of the warmer object became to decrease. The process is continue until the energy of these objects became equal, i.e. when their temperatures are equal.

Convection is the process of transferring the thermal energy trough the movement of a gas or liquid (fluid).
For example: if you turn on the electric fan oven the temperature in the room is increasing.

Radiation is the process of heat transfer by radiant energy that travels through by electromagnetic waves.
This is the way by which the Earth receive heat from the Sun.

Heat is the main reason to observe occurrences as:
  • Vaporization - when the state of the object is change the state from a liquid state to a gas state - for example when water changes it's state from a running water to a vapor.
  • Condensation - is when the object change the state from a gas state to a liquid state - for example when water change its state from a vapor to a drinking water.
  • Freezing is a change from liquid to solid - for example when the water change it's state from drinking water to an ice.
  • Melting is the process of changing the object state from solid to liquid. For example when water change its state from ice to drinking water.