Facts About Water

Hot Water Freezes Faster Than Cold Water

 At what temperature does water freeze? It would seem – the simplest question that even a child can answer: the freezing point of water at a normal atmospheric pressure of 760 mm Hg is zero degrees Celsius.

Conditions and types of water

Water on planet Earth can take on three main states of aggregation: liquid, solid and gaseous, which can change into different forms and coexist at the same time (icebergs in seawater, water vapor and ice crystals in the clouds in the sky, glaciers and free-flowing rivers ).

Depending On The Characteristics Of Its Origin, Purpose And Composition, Water Can:

  • fresh;
  • mineral;
  • nautical;
  • drink (here we take tap water);
  • to rain;
  • thawed;
  • broke;
  • structured;
  • distilled;
  • deionized.

The presence of hydrogen isotopes makes water:

  • lightweight;
  • heavy (deuterium);
  • super heavy (tritium).

We all know that water can be soft and hard: this indicator is determined by the content of magnesium and calcium cations.

Each of the types and states of water aggregation we have listed has its own freezing and melting temperatures.

Freezing Point Of Water

Why does water freeze? Ordinary water always contains a certain amount of suspended particles of mineral or organic origin. These can be small particles of clay, sand or house dust.

When the ambient temperature drops to certain values, these particles take on the role of centers around which ice crystals begin to form.

Air bubbles can also become crystallization nuclei, as can cracks and damage to the walls of a vessel containing water. The speed of the water crystallization process is largely determined by the number of these centers: the more there are, the faster the liquid freezes.

Under normal conditions (at normal atmospheric pressure), the temperature of the phase transition of water from a liquid to a solid state is 0 degrees Celsius. It is at this temperature that the water freezes in the street.

Why Does Hot Water Freeze Faster Than Cold Water?

Hot water freezes faster than cold water – this phenomenon was noticed by Erasto Mpemba, a student from Tanganyika. His experiments with an ice-making mass showed that the freezing rate of a heated mass is much higher than that of a cold one.

One of the reasons for this interesting phenomenon, called the “Mpemba paradox”, is the higher heat transfer of a hot liquid, as well as the presence in it of a greater number of crystallization nuclei compared to cold water.

Is The Freezing Point Of Water And Altitude Related?

When the pressure changes, often associated with being at different altitudes, the freezing point of water begins to differ radically from the standard characteristic for ordinary conditions.

Crystallization of water at height occurs at the following temperature values:

paradoxically, water freezes at an altitude of 1000 m at 2 degrees Celsius;

at an altitude of 2000 meters this already happens at 4 degrees Celsius.

The highest freezing point of water in the mountains is observed at an altitude of more than 5000 thousand meters (for example, in the Fan Mountains or in the Pamirs).

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