Plano-Cylindrical Concave Lens, -17 Diopter, 50 x 50mm Material_Borosilicate Glass stamped (Zn) to identify it

stamped (Zn) to identify it against the rest of the metal-cube series

illustrating the biogeochemical cycles that link them

6 inches for clean pinhole-imaging and diffraction studies

curving visibly under heat as the two metals expand at different rates

this five-piece weight set bundles machined steel shafts from 50 to 1000 grams on a wooden storage block

Plano-Cylindrical Concave Lens, -17 Diopter, 50 x 50mm Material_Borosilicate Glass stamped (Zn) to identify itPlano cylindrical concave lens at 50 by 50mm with 17 diopter power, the cylindrical concave curvature spreading light along a single axis for line focus and divergence demos.