Question

what happens after the process of convection current when all particles are heated?

Answer 1

Is the movement of thermal energy through a material without the particles in the material moving.

Glass, wood and plastic are all poor conductors of heat.

Heat is the kinetic energy of particles as they vibrate. If we heat the particles at one end of a material the particles at that end vibrate more (have more kinetic energy) and bump into the neighbouring particles which causes them to vibrate more. They collide with their neighbours and so the energy is passes from one particle to another through the material.