Law of reflection
Ley de la reflexión de la luz
- Date
- c. 300 BCE · confidence medium
- Place
- Alexandria, Egypt
- Credited to
- Euclid; Heron of Alexandria
- People
- 👤 Euclides333 BCE–285 BCE
- Field
- Communication
What was discovered
The angle of incidence equals the angle of reflection and rays travel in straight lines. Euclid states it in his 'Optics' and Heron derives it from the principle that light takes the shortest path, the first variational principle in physics.
Heron (1st century CE) adds the shortest-path explanation in his 'Catoptrics'.
What it led to
- Geometrical optics
- Fermat's principle of least time
- Design of curved mirrors and reflecting telescopes
- Variational principles (Maupertuis, Hamilton)
Built on
- Euclidean axiomatic geometryc. 300 BCE
- Euclidean geometry
- Polished bronze mirrors
Made possible
- On Burning Mirrors: focus of the parabolic mirror (Diocles)c. 200 BCE
- Hero's Catoptrics: reflection follows the shortest pathc. 60
- Ibn Sahl's law of refraction984
- Parabolic mirrors
- Newton's reflecting telescope
- Lighthouses and reflectors