Heat transfer in solids occurs by:

**The reasoning** Heat transfer in solids happens through **conduction** — the process where thermal energy passes from molecule to molecule through direct contact. Picture it like this: when you heat one end of a metal spoon, the molecules there vibrate faster. They bump into neighboring molecules, making *them* vibrate faster too. This chain reaction continues until heat spreads through the entire solid. The molecules don't actually move from place to place; they just pass energy along while staying in position. This is why solids, especially metals, are good conductors — their tightly packed particles transfer energy efficiently. **Why the wrong options tempt you** - **Convection** requires fluid movement (liquids/gases flowing), but solid particles are fixed in place, so no bulk movement occurs. - **Radiation** transfers heat through electromagnetic waves (like the sun warming your skin), which *can* happen with solids but isn't the *primary* method inside them. - **Evaporation** is a cooling process involving liquids changing to gas — nothing to do with heat moving through solids. **Quick takeaway** In solids, particles can't flow, so heat travels by the domino effect of vibrating molecules — that's conduction.