Sublimation vs Heat Transfer
Sublimation and heat transfer are two topics discussed under energy and state of matter. These concepts are very important in the study of fields such as thermodynamics, matter transition, power generation and power transfer and in almost every mechanical system. A clear understanding in these concepts are required in order to excel in the above fields. In this article, we are going to discuss what sublimation and heat transfer are, their definitions, applications of heat transfer and sublimation, some common examples for heat transfer and sublimation, their similarities and finally the difference between heat transfer and sublimation.
One must first understand the concept of heat, to understand the concept of heat transfer. Thermal energy, also known as heat, is a form of internal energy of a system. Thermal energy is the cause for the temperature of a system. The thermal energy occurs due to the random movements of the molecules of the system. Every system having a temperature above absolute zero has a positive thermal energy. The atoms themselves do not contain any thermal energy. The atoms have kinetic energies. When these atoms collide with each other and the walls of the system, they release thermal energy as photons. Heating such a system will increase the thermal energy of the system. Higher the thermal energy of the system higher will be the randomness of the system. Heat transfer is the movement of heat from one place to another. When two systems, which are thermally contacted, are in different temperatures, heat from the object at the higher temperature will flow to the object with a lower temperature until the temperatures are equal. A temperature gradient is necessary for a spontaneous heat transfer. The rate of heat transfer is measured in watt, whereas the amount of heat is measured in joule. The unit watt is defined as joules per unit time.
What is Sublimation?
When a solid is heated up to the melting point of the solid, it will change its phase to a liquid. When the liquid is further heated up to the boiling point, it will change the state to a gas. This is not the case with sublimation. Sublimation is the process of directly changing the state from solid to gas. This is observed only under special situations in special materials. Pure naphthalene is such a subliming material. Another substance that sublimes is solid carbon dioxide, which is also known as dry ice. Iodine crystals, ice and snow behaves as subliming material under some conditions. The misty gas evolving from an ice cube is the subliming ice.
What is the difference between sublimation and heat transfer?
• Sublimation is a change of the state of matter, whereas heat transfer is a change of state of energy.
• Heat can be converted to other forms of energy and then be transferred, but in sublimation, no such change is possible.
• Sublimation is also a heat transfer from the solid state of matter to gas state of matter.