ice point

The ice point is the freezing point of water, which is 0° Celsius or 273.15 kelvins at standard atmospheric pressure. Ice is the solid form of water, produced when water vapor or liquid water freezes below 0°C (32°F).12

Water exhibits unusual density behavior: it becomes denser as it cools down to 4°C (39.2°F). Below this temperature, water expands and becomes less dense as it approaches its freezing point. This is why ice floats on water, allowing aquatic life to survive in colder temperatures.23

Phase changes, like freezing or melting, involve the absorption or release of energy, known as latent heat. Some substances, like dry ice (solid carbon dioxide), can convert directly from a solid to a gas without becoming liquid, a process called sublimation.4567