HEAT Transfer: Heat is transferred from one place to another in substance due to temperature difference. Three modes of Transmission of heatConductionConvectionRadiationHeat dissipates from one place to another by molecular vibrationHeat is transfer from one place to another by transfer of moleculesIt transfers heat in the form of electromagnetic waveConduction is relevant to solid only.Convection happens in liquid or gasesIt can heat any form of material.Need MEDIUM to transfer heatNeed medium to transfer heatNo need of mediumGood Conductor- The objects which transfer heat easily. Ex- metals, human body etcBad Conductor- The objects which do not transfer heat easily. Ex- Wood, Air, etc.Thermal INSULATOR- No heat is transferred by any means.Ex- Abonite, asbestos etc.When molecules are heated they HEADED upward and upper molecules go downward and this cyclic process continues. Boiling of fluidHeat travels in terms of energy packets or wavesThe heat absorbed by body gain energy Radiations of Sun EVAPORATION: In this process, the liquid form a substance tends to convert in the gaseous phase on the uppermost surface due to heat and pressure.Condensation: In this process, the gaseous phase of an object tends to convert into liquid form due to pressure and temperature.EXPLANATION: Once the lower molecules of pot get heated comes at the top.And the upper molecules are heavy therefore goes down due to gravity.This cyclic process continues heating occurs.While heating the water Convection takes place.