Here's why:
* Heat and Molecular Motion: Solids have tightly packed molecules that vibrate in place. Heat energy increases the vibration of these molecules.
* Breaking Bonds: As the molecules vibrate more, they break free from the strong bonds holding them together in a solid structure.
* Transition to Liquid: This increased freedom of movement allows the molecules to flow past each other, which is the defining characteristic of a liquid.
Example: Think about ice cubes. When you add heat (from your hand or the room temperature), the ice melts into liquid water.
Important Note: While heat is the primary factor, the specific melting point of a substance also plays a role. Each substance has a specific temperature at which it transitions from solid to liquid.
