Here's why:

* Conduction is the transfer of heat through direct contact between substances.

* Metals are excellent conductors because they have free electrons that can easily move throughout their structure.

* When one end of a metal object is heated, the electrons in that region gain kinetic energy and start moving faster.

* These energized electrons collide with neighboring electrons, transferring energy and causing them to move faster as well.

* This process continues down the object, resulting in the transfer of heat.

In short, the free electrons in metals are the main players in heat conduction.

While other particles like atoms and molecules can also contribute to heat transfer in some materials, their contribution is typically less significant than that of electrons in metals.