Leonardo da Vinci’s 500-year-old ‘paradox’ finally solved: what scientists have found

Physicists have made an important discovery that explains the “wrong” movement of air bubbles in water. IFLScience.

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Over 500 years ago, Leonardo da Vinci watched air bubbles rise in water, and he noticed that some of the bubbles move in a spiral or zigzag pattern instead of rising in a straight line towards the surface. Leonardo da Vinci noticed that only large bubbles, and not small air bubbles, rise to the surface in this way, although the same forces act on each of them. For centuries, no one offered an explanation for this phenomenon, which was called the “Leonardo da Vinci paradox”.

But Miguel Errada of the University of Seville, Spain, and Jens Eggers of the University of Bristol, UK, solved the mystery. A new study has shown that air bubbles can reach a critical size that contributes to their unstable movement due to the interaction between the flow of water around them and small changes in their shape. According to scientists, the bubbles change under the influence of forces from the water, and, in turn, the shape of the bubble changes the nature of the movement.

“Rising air bubbles in water are affected by many intersecting forces, such as the viscosity of the fluid, surface friction, and any contaminants that distort the shape of the bubbles and change the dynamics of the water flowing around them,” Errada says.

The scientists created mathematical models and compared their results with previous experiments conducted in “ultrapure water”. They found that the bubbles periodically tilt, which changes their shape. Thus, one of the sides of the bubble becomes more slippery, so the water flows around it faster. This reduces the pressure on this side and the bubble returns to its original state, but then the transformation cycle is repeated again.

Their simulations showed that bubbles deviate from a straight path in water when their spherical radius exceeds 0.926 millimeters, which is about the size of a pencil tip. Now the authors of the study want to understand more precisely how water pollution affects the results of studying the behavior of air bubbles. Because very clean water was not available in the 16th century, so Leonardo da Vinci had to deal with definitely polluted water.

As already wrote Focusscientists tested the plausibility theory of the Baghdad “battery”. Almost 100 years ago, an earthenware jug was found, which is about 2 thousand years old. And scientists have suggested that this capacity was used as an ancient battery.

Same Focus wrote that scientists discovered life in Leonardo da Vinci’s iconic self-portrait. It turned out that the picture contains something unique and still unknown to science.