Refraction

Refraction is a phenomenon that takes place when light passes through elements characterized by different physical and chemical properties, for example, when passing from air into water. In this passage, the light ray changes trajectory, even while remaining within the same plane.

In order to analyze this phenomenon and to see how rays of sunlight penetrate into the sphere of air around the earth, as he himself wrote, Leonardo proposed an experiment: one takes two balls of glass, one twice the size of the other. The two balls are filled with water, and next the smaller glass ball is enclosed within the larger. One can then observe how a light ray penetrating the water-filled glass balls changes direction various times.

In spite of his intuition, Leonardo did not succeed in formulating a law on this.This exhibit offers a schematic representation of the experiment proposed by Leonardo, with the white cylinder indicating the light source and the black cylinder indicating the light ray’s point of arrival.