Actually temperature implies the physical motion of the molecules in liquid/gas OR the electrons in lattice, which interchanges with the infrared photons during collision in lattice or within the molecules. Two systems are called to be at the same temperature when the speed of generation and consumption of the IR photons is same.
Now in the case of latent heat energy, the generation of IR photons from the lattice and the next phase, let us say liquid remains the same. This happens because in the state transition the consumption and production of IR photons is not the same because a part of the electrons kinetic energy is lost in breaking the lattice bonds. That energy is never recovered. In fact under the right conditions a phase change can be a cooling thing, like evaporation pots.
When ice is heated from -5 degree C to 0 degree C the kinetic energy (movements) of the molecules gradually increase, then from 0 degree C (ice) to 0 degree C (water) the intermolecular bonds are broken by the heat. When the first bond breaks, simultaneously why kinetic energy (movements) of the molecules does not increase (i.e. temperature does not change)? Why after all the molecular bonds are broken, the kinetic energy (movement) of the molecules again increases raising the temperature (i.e. after absorbing latent heat)?
Thanks parag for still following the question stream. This was the original question. Kindly share your views.
Barid Baran Lahiri
Indira Gandhi Centre for Atomic Research
United Institute of Technology
Krishnananda G Shastri
Karnatak University, Dharwad
IK Elektronik R&D
Sajjad Ahmed Memon
Nuclear Institute of Medicine & Radiotherapy (NIMRA)
Jagdishprasad Jhabarmal Tibrewala University
Institut de recherche et de développement en agroenvironnement
National Institute of Technology, Durgapur