Fresnellinse

Stations-ID: D056

Instructions:

Lenses can also be very flat! This one will magnify, demagnify, distort and turn the world upside down.

• Where do you and your partner have to stand to see each other through the lens?
• Stand on both sides of the lens with a partner, looking at each other.
• At which point can your partner see you clearly, at which point not?
• What happens when your partner walks slowly away from the lens?
• Look at the lenses in the window. Do they all look the same or different?

Both the French Georges-Louis-Leclerc de Buffon (1707-1788) and Marie Jean Antoine Nicolas Caritat, Marquis de Condorcet (1743-1794) as well as the Scottish kaleidoscope inventor Sir David Brewster (1781-1868) had already considered a thin and light lens shape made of concentric glass rings. The physician and engineer Augustin-Jean Fresnel (1788-1827), who was appointed by the French government as secretary of a specially founded beacon authority, came up with the idea of using such lenses for the improvement of beacon optics. The first “Fresnel apparatus” was not put into operation until Fresnel’s death in the year 1832.