Accession No
2759
Brief Description
6 diffraction gratings, c.1920
Origin
Maker
Class
optical
Earliest Date
1920
Latest Date
1920
Inscription Date
Material
glass; paper (cardboard)
Dimensions
each plate 81 x 107mm overall box length 278mm; breadth 215mm; height 32mm
Special Collection
Provenance
Donated, 15/08/1981. belonged to A.C. Mengies
Inscription
Description Notes
6 reflection gratings ruled on glass, packed in 2 cardboard boxes.
Condition
References
Events
Description
Diffraction grating
Grimaldi (an Italian physicist) saw that the edges of shadows are not completely sharp, but have fringes. Only later, in 1785, when multiple edges were placed next to one another to form a grating, was the full importance of this observation elucidated.
A diffraction grating consists of very closely spaced lines on a reflecting surface (the line ruling process must be very precise). The lines disperse light into component wavelengths (much like a prism does) and this is useful for precise determination of the magnitude of wavelengths.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:43650
Images (Click to view full size):
