In: Mechanical Engineering
Conduction in liquids:
During conduction, heat always transfers from the hotter body to
the colder body. Temperature is a reflection of the average kinetic
energy of the particles of a substance. As the temperature
increases, the kinetic energy of the fluid particles also
increases. This causes the particles to vibrate. During this
vibrations of particles, the warmer and faster particles collide
into cooler and slower particles. When this occurs, energy is moved
from the warmer particles that have more energy to the cooler
particles that have less energy. This process continues until the
system attains equilibrium and both objects have the same
temperature.
Conduction in gases:
Conduction in gases is mainly due to the molecular momentum and thermal diffusion which is caused by collisions between the particles. Hotter particles have high kinetic energy and they move in random directions during this movement they collide with cooler particles and lose some energy and hence transfer some heat to cooler particles and they slow down. This process continues umtill all the particles attain same temperature.