Here's why:
* Conduction is the transfer of heat through direct contact between molecules.
* When two objects touch, their molecules collide and transfer energy.
* The hotter object has molecules with higher kinetic energy, and they transfer some of this energy to the molecules of the colder object.
* If the objects are not touching, there's no direct contact between their molecules, and conduction cannot happen.
Example:
Imagine holding a hot cup of coffee. The heat from the coffee is transferred to your hand through conduction because your hand is in direct contact with the cup.
