Jäätuminen

Jäätyminen refers to the process of freezing, specifically the phase transition of a liquid into a solid. In the context of water, this occurs when its temperature drops to its freezing point, which is 0 degrees Celsius (32 degrees Fahrenheit) at standard atmospheric pressure. During this transition, the molecules of the liquid lose kinetic energy and slow down. As they cool further, attractive intermolecular forces become strong enough to overcome the molecular motion, causing the molecules to arrange themselves into a more ordered, crystalline structure. For water, this structure is ice.

The freezing point of a substance can be influenced by external factors such as pressure and the presence of dissolved impurities. For example, adding salt to water lowers its freezing point, a principle utilized in de-icing roads. Conversely, increasing pressure generally raises the freezing point of most substances, though water is an exception where increased pressure lowers its freezing point slightly.

The process of jäätyminen releases latent heat of fusion, meaning that even as the substance is transitioning from liquid to solid, it continues to emit energy at a constant temperature until the entire substance has solidified. This phenomenon is important in various natural processes, such as the formation of ice in cold climates and its impact on weather patterns. In industrial applications, controlled freezing is used for preservation, material processing, and in refrigeration technologies. The opposite process, melting or thawing, is the transition from solid to liquid.