Water is one of the most amazing things on the Earth. Without it, there would be no life and our planet would be a completely different place. Until now, it is considered as water exists in one liquid phase. But now, this consideration going to be changed.

Researchers have now discovered that water exists in not one, but two distinct liquid phases. Each liquid phase has big differences in structure and density. Scientists from Stockholm University in Sweden have provided evidence that the liquid water is not a single phase. In fact, it is just a fluctuation between two forms, high and low density.

Lars G.M. Pettersson, one of the scientist said, “The new results give very strong support to a picture where water at room temperature can’t decide in which of the two forms it should be, high or low density, which results in local fluctuations between the two.”

“In a nutshell: Water is not a complicated liquid, but two simple liquids with a complicated relationship.”

Scientists Show Water Exists in Two Different Liquids
Pictured is an artist’s impression of the two forms of ultra-viscous liquid water with different density. On the background is depicted the x-ray speckle pattern taken from actual data of high-density amorphous ice, which is produced by pressurizing water at very low temperatures.
Credit: Mattias Karlén

Water exists in three distinct phases: liquid water, solid ice, and water vapor. It can also exist as a strange plasma-like state. During the study, scientists have identified 70 properties of liquid water that are entirely unique from all other liquid substances.

The phenomenon is that long been debated, there is more than one liquid phase of water. Scientists already know that ice can exist in distinct high and low-density forms. But ice also exists in another form known as amorphous ice that consists disordered molecules. Amorphous ice is likely the most common type of solid water. It also can flip between distinct high and low-density versions.

Due to this, scientists thought liquid water could do the same thing. Scientists used two different types of X-ray imaging to track the movement and distance between H2O molecules as water transitioned from an amorphous, glassy, frozen liquid state, to a viscous liquid, and even more viscous liquid with lower density. They saw two distinct liquid phases.

One of the researchers, Anders Nilsson said, “The new remarkable property is that we find that water can exist as two different liquids at low temperatures where ice crystallization is slow.”

Importantly, the research adds another important piece to the puzzle that’s beginning to gradually reveal just how strange and fascinating this ubiquitous molecule really is.

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