Leonardo da Vinci's

Leonardo da Vinci’s “air bubble paradox,” which refers to bubbles spiraling their way to the water’s surface instead of rising in a straight line, had remained unanswered.
There are thousands of mysteries that humanity has not been able to solve, not even through science, one of them was an experiment carried out by Leonardo da Vinci more than five centuries ago, which has now been solved by two researchers.

Leonardo da Vinci’s “air bubble paradox,” which refers to air bubbles moving in a spiral or zigzag on their way to the surface of the water, rather than rising in a straight line, had remained unanswered. , until now.

For centuries, scientists have tried to explain why this happens, without success. But a few days ago, researchers from the University of Seville (Spain) and the University of Bristol (England) claimed to have a scientific answer to this phenomenon.
Professors Miguel Ángel Herrada, from the University of Seville, and Jens G. Eggers, from the University of Bristol, have discovered a mechanism to explain the unstable movement of bubbles that rise in water, in research published in the Proceedings of the National Academy of Sciences (PNAS).

“The authors of this new work have developed a numerical discretization technique to accurately characterize the air-water interface of the bubble, which allows them to simulate its movement and explore its stability,” explains the University of Seville in a statement.

The research explains that their simulations fit perfectly with high-precision measurements of unstable bubble motion and show that bubbles deviate from a straight trajectory in water when their spherical radius exceeds 0.926 millimeters, a result within 2 % of the experimental values obtained with ultrapure water in the 90s.

The explanation expected for 500 years

What the scientists discovered is that when the air bubbles reach a certain radius they are forced to follow new and unstable trajectories. This occurs due to the interaction between the flow of water and the subtle disintegration of its forms.
The researchers propose a mechanism for bubble track instability in which periodic tilting of the bubble changes its curvature, affecting upward velocity and causing a wobble in the bubble’s track, tilting the left side up. of the bubble whose curvature has increased.

“Then, as the fluid moves faster and the fluid pressure drops around the high-curvature surface, the pressure imbalance returns the bubble to its original position, restarting the periodic cycle,” the authors explain in the study. .

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