Artificial Intelligence reveals that water could be two liquids at once

The artificial intelligence allowed for the first time the identification of molecular evidence for a theory that suggests that water could behave like two different liquids at the same time.

The finding was presented in the journal Nature Physics and arises from a study that combined massive simulations with artificial intelligence. The researchers claim that this technology was able to detect patterns that had been impossible to observe for decades.

What artificial intelligence discovered about water

For years, scientists have hypothesized that water exists in two distinct liquid states at the molecular level: one of high density and another of low density.

According to this theory, both structures constantly transform into each other. However, until now, there was no direct evidence to observe this behavior.

Xiao Cheng Zeng, a physical chemist at the City University of Hong Kong and co-author of the study, explained that the so-called two-state hypothesis has sparked scientific interest for decades, although concrete evidence was lacking.

How the research team used artificial intelligence

To tackle the problem, the team turned to an unsupervised deep learning system, an artificial intelligence technique designed to find patterns without prior instructions.

The researchers conducted molecular dynamics simulations using the GROMACS package and analyzed hundreds of thousands of water molecules.

The process generated tens of millions of data points on molecular movements and interactions.

According to Zeng, a task of this nature could have taken nearly a decade using traditional methods, while the analysis with artificial intelligence required approximately a year and a half.

What patterns did artificial intelligence find in water molecules

Artificial intelligence identified variables capable of describing how a water molecule transitions from a denser structure to a less dense one and vice versa.

The researchers observed that the conversion between both states can follow different energy pathways depending on the system's conditions.

In most cases, the transition occurs through a simple pathway with a single energy barrier.

However, near the boundary between both states, molecules can follow a more complex pathway with three different barriers.

Why water exhibits different behaviors than other liquids

The study attempts to explain several particular properties of water that scientists have been investigating for decades.

Among them is the fact that water increases its density when cooled to approximately 4 °C and then begins to expand, a phenomenon that allows ice to float.

It also analyzes characteristics related to viscosity and how it responds to temperature changes.