The Science Behind Supercooled Water

When water reaches its freezing point, 32 degrees Fahrenheit, it becomes ice… right? Actually, there is a period between water turning from liquid to solid that can happen before your eyes! This super cool transition is known as supercooling water.

Supercooled water is water that remains in its liquid state far below the freezing point. But in order for this to work, the water must be very purified so that the impurities in the water don’t create a place for crystallization to occur. 

Essentially, the arrangement of molecules in water determines its state of matter. When the molecules are not touching and flowing freely, the water is liquid. When the molecules come together and lock into place, it becomes a solid, or ice.

Since this occurs naturally in impure water, we must initiate the nucleation process (the first step of crystallization) to observe the supercooling process. That’s where the fun part comes in! Disturbing the molecules by shaking, pouring, or banging on a surface is the catalyst to the crystallization process.

Are you ready to try to supercool your own water? ThoughtCo. recommends two different methods to try to observe this amazing phenomenon:

Supercool Bottled Water

  1. Place an unopened bottle of purified water (Fiji is a reliable brand) in the freezer undisturbed.
  2. After two and a half hours, carefully remove the supercooled water from the freezer.
  3. Initiate crystallization by either shaking the bottle or opening it and pouring the supercooled water over a piece of ice.

Supercool Water in a Glass

  1. Pour about two tablespoons of purified water into a clean glass.
  2. Place the filled glass into a bowl of ice. Make sure the level of ice is higher than the level of water in the glass!
  3. Sprinkle a few tablespoons of salt onto the ice, carefully as to not get any salt in the water.
  4. Wait 15 minutes for the water to cool below the freezing point, thus becoming supercooled.
  5. Initiate the process by either pouring it over a piece of ice or dropping a piece of ice into the glass. 

The process of supercooling water shows just how amazing H2O is. Watching science occur before our very eyes is a rare occurrence. Water truly is super cool!