What Is the Melting Point of Water?

The melting point and freezing point of water may not be the same temperature.
For most purposes, you can consider the melting point of water to be 0°C or 32°F. Pieter Kuiper, Creative Commons License

The melting point of water is not always the same as the freezing point of water! Here is a look at the melting point of water and why it changes.

The melting point of water is the temperature at which it changes from solid ice into liquid water. The solid and liquid phase of water are in equilibrium at this temperature. The melting point depends slightly on pressure, so there is not a single temperature that can be considered to be the melting point of water. However, for practical purposes, the melting point of pure water ice at 1 atmosphere of pressure is very nearly 0 °C, which is 32 °F or 273.15 K.

The melting point and freezing point of water ideally are the same, especially if there are gas bubbles in water, but if the water is free of nucleating points, water can supercool all the way down to −42 °C (−43.6 °F, 231 K) before freezing. So, in some cases, the melting point of water is considerably higher than its freezing point.

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Helmenstine, Anne Marie, Ph.D. "What Is the Melting Point of Water?" ThoughtCo, Feb. 16, 2021, thoughtco.com/what-is-the-melting-point-of-water-609414. Helmenstine, Anne Marie, Ph.D. (2021, February 16). What Is the Melting Point of Water? Retrieved from https://www.thoughtco.com/what-is-the-melting-point-of-water-609414 Helmenstine, Anne Marie, Ph.D. "What Is the Melting Point of Water?" ThoughtCo. https://www.thoughtco.com/what-is-the-melting-point-of-water-609414 (accessed March 28, 2024).