Concept:Heat is transferred in conduction by free electrons within a material.
Explanation:When a material is heated, its particles gain kinetic energy and vibrate more rapidly.
These vibrations are passed from one particle to the next, but the main carrier of heat is the free electrons.
In metals, free electrons move quickly through the lattice and carry thermal energy from hotter regions to cooler regions.
This is why materials with many free electrons, such as metals, are excellent conductors of heat.
Therefore, at the molecular level, conduction involves the movement of free electrons rather than free atoms, molecules, or solids.
Answer:Free electrons.