# This da Vinci Doodle Holds a Secret

## More than 500 years later, we're still learning more about da Vinci's genius.

University of Cambridge/CC-BY-NC-ND 4.0

When you doodle, you're probably drawing something like a square that magically turns into a 3D cube or your boss with devil horns. When Leonardo da Vinci was doodling, he was figuring out some of the fundamental laws of physics.

In a , Professor Ian M. Hutchings of the University of Cambridge argues that a sketch from da Vinci's journals shows that the Renaissance-era polymath was already working out his own ideas about the concepts of friction years earlier than previously thought.

Hutchings argues that the sketches, which had previously been seen as inconsequential, were the first known place that da Vinci began to work out his theory of friction (or "tribology"). Da Vinci is known to have performed some of the first scientific work in figuring out friction, but when he began has remains a mystery.

The page in question is from 1493 and is currently held at the Victoria and Albert Museum in London. The sketch is done in da Vinci's "mirror writing" style, done from right to left. When first examined by a director of the Victoria and Albert Museum in the 1920s, the director dismissed the notations as "irrelevant notes and diagrams in red chalk."

But Hutchings argues that the sketch actually shows blocks on the ground being being pulled by a weight attached to a pulley—the same type of experiment you might do today in a high school physics class.

"The sketches and text show Leonardo understood the fundamentals of friction in 1493," said Professor Hutchings in . "He knew that the force of friction acting between two sliding surfaces is proportional to the load pressing the surfaces together and that friction is independent of the apparent area of between the two surfaces. These are the 'laws of friction' that we nowadays usually credit to a French scientist, Guillaume Amontons, working two hundred years later."

Da Vinici, well-known for his many mechanical sketches and experiments, was fascinated by the laws governing how exactly physical objects moved, with friction obviously playing a huge role in that. "Leonardo's sketches and notes were undoubtedly based on experiments, probably with lubricated s," said Hutchings. "He appreciated that friction depends on the nature of surfaces and the state of lubrication and his use and understanding of the ratios between frictional force and weight was much more nuanced than many have suggested."

Still, while the sketches show a glimpse into the mind of a genius, they had little to do with the actual systemic theory of friction that was developed by the French scientist Guillaume Amontons nearly 200 years later. If only someone had looked at da Vinci's doodles a little closer.

Source: via