How does cooling a liquid cause it to freeze into a solid?

Cooling a liquid causes it to transition into a solid by reducing the kinetic energy of its constituent particles (atoms, molecules, or ions). As the liquid cools, these particles move more slowly, allowing attractive forces between them to overcome their thermal energy.1

At the freezing point, the particles reach a density and energy state where they begin to arrange themselves into a rigid, ordered structure, often forming a crystal lattice. This process typically begins with nucleation, where a small cluster of particles forms a stable seed that facilitates further growth. During this phase change, the substance releases its heat of fusion—the energy that must be removed from the liquid to allow the particles to settle into a solid state.1234

While most substances form crystalline solids, rapid cooling can sometimes bypass crystallization, leading to the formation of amorphous solids like glass, where the material becomes increasingly viscous until it behaves as a rigid solid.3