schlie|ren

schlie|ren «SHLIHR uhn», noun, adjective.

–n.pl.

1. irregular, dark or light streaks occurring in igneous rock because of varying proportions of the minerals present.

2. Physics. a) areas in a medium where refraction varies as a result of differences in density. b) the shadows cast on a screen when light is refracted by these areas so that it cannot hit the screen.

–adj.

1. of or having to do with schlieren: »

Focused shadowgraphs were taken through windows. They are known as schlieren photographs and show the shock waves about the model (Science News Letter).

2. using schlieren to study substances or their behavior in motion, to indicate irregularities, as in glass, heat convection, or shock wave patterns: »

This schlieren system is probably best known from its use in photographing the shock waves formed by air passing at great speeds over airplane models in wind tunnels (Science News Letter).

╂[< German Schlieren < Schlier marl, or perhaps < Schliere slime]