Inverted images and focal points of concave mirrors (Shen Kuo)
Imagen invertida y foco de los espejos cóncavos (Shen Kuo)
- Date
- 1088 · confidence high
- Place
- Runzhou (Zhenjiang), Jiangsu, China
- Credited to
- Shen Kuo
- Field
- Communication
What was discovered
In the Dream Pool Essays, Shen Kuo explains that the inverted image of a pagoda through a hole, or in a concave mirror, results from rays crossing at one point, and describes the focus of concave mirrors. He also discusses why magic mirrors transmit their pattern.
It continues the Mohist tradition; the merit is the geometrical explanation of ray crossing and focus in one framework, not the discovery of the inverted image, which was already known.
What it led to
- analysis of magic mirrors through surface curvature
- the Chinese tradition of mirror and pinhole geometrical optics
- diffusion of the Essays as a scientific encyclopedia