Optically Worked Double Concave Glass Lens, 38mm Diameter Focal Length:50mm this silk square gives friction

this silk square gives friction rods a strong positive charge for triboelectric and electrostatic demonstrations

SUPERIOR TOLERANCES || With superior chemical durability & heat/cold tolerance

configurable across many ratios for transformer-action demonstrations

Refill kit provides replacement materials for AP Biology investigation #6 cellular respiration with pre-measured chemicals and documentation

biuret reagent

Optically Worked Double Concave Glass Lens, 38mm Diameter Focal Length:50mm this silk square gives frictionGround and polished glass surfaces produce ray tracing quality images for demonstrating virtual image formation through diverging lenses.