Supercooled liquids are substances that remain in a liquid state even when cooled below their normal freezing point. This occurs because the molecules do not have enough energy to arrange themselves into a solid structure, despite the lower temperature. Common examples include water and certain types of glass. These liquids can exist in a metastable state, meaning they can remain liquid for extended periods but can suddenly freeze if disturbed or if impurities are introduced. Supercooled liquids are important in various fields, including materials science and cryogenics, as they help researchers understand phase transitions and molecular behavior.