Leonardo da Vinci sketched a tribometer to compare the friction of surfaces.
A tribometer is an instrument used to study friction and related properties between contacting materials. Leonardo’s notebooks contain experiments and diagrams that investigate how friction changes with load, contact area, and surface conditions. His work is often cited as an early systematic contribution to tribology, the science of friction, lubrication, and wear.
Leonardo did not use the modern word “tribometer,” which was coined later. The label is applied by historians and engineers to describe the function of his experimental apparatus. This is why the instrument should not be confused with a barometer, which measures atmospheric pressure, or an odometer, which measures distance traveled.
His friction studies were part of a much wider interest in mechanics. By recording observations and comparing variables, Leonardo moved beyond purely artistic sketches toward repeatable engineering investigation.