secchi disc

views updated Jun 11 2018

secchi disc A disc used in a simple method for measuring the transparency of water. The disc is 20 cm across and divided into alternate black and white quadrants. It is lowered into water on a line until the difference between the black and white areas just ceases to be visible, at which point the depth is recorded. The secchi disc provides a convenient method for comparing the transparency of water at different sites. The disc was invented by the Italian Jesuit and eminent astrophysicist Angelo Secchi (1818–78).

secchi disc

views updated May 14 2018

secchi disc A disc used in a simple method for measuring the transparency of water. The disc is 20 cm across, and divided into alternate black and white quadrants. It is lowered into water on a line until the difference between the black and white areas just ceases to be visible, at which point the depth is recorded. The secchi disc provides a convenient method for comparing the transparencies of water at different sites.

Secchi disc

views updated May 08 2018

Secchi disc A device used in a simple method for measuring the transparency of water. The disc is 20 cm across, and divided into alternate black and white quadrants. It is lowered into the water on a line until the difference between the black and white areas just ceases to be visible, and this depth is recorded. The Secchi disc provides a convenient method for comparing the transparencies of water at different times.

More From encyclopedia.com