Britannica
Sources used in this answer
How did Claudius Ptolemy contribute to the study of optics?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Ptolemy
Ptolemy's theory of the solar system.
Claudius Ptolemy made significant contributions to the study of optics through his treatise Optica, written toward the end of his life. His work is particularly noted for its commitment to empirical analysis, which distinguished him from many of his contemporaries.1
Key contributions include:
- Reflection: While other Greek writers relied on philosophical arguments, Ptolemy established the principle that an object and its mirror image make equal angles to a mirror by physically measuring angles of incidence and reflection using a graduated disk.12
- Refraction: He conducted experiments to measure how lines of sight are refracted when passing between materials of different densities, such as air, water, and glass.1
Although Ptolemy’s experimental approach was advanced for his time, he did not successfully identify the exact mathematical relationship between the angles of incidence and refraction, known today as Snell’s law.1