Optical Lens Set, 2", 6-Piece, Convex and Concave Base Size_9 x 9" Pith balls suspended both inside

Pith balls suspended both inside and outside a charged metal cylinder make visible proof that electrostatic charge resides only on the outer surface of a conductor

Shatter-resistant acrylic Guinea-and-feather tube at 100cm long and 44mm outer diameter with a stopcock

Higher-current 1000-ohm 0

and sterilization in chemistry and biology laboratories

Optical Lens Set, 2", 6-Piece, Convex and Concave Base Size_9 x 9" Pith balls suspended both insideSPHERICAL Each lens is spherical in shape and measures 2" (50mm) in diameter FOCAL LENGTH VARIETY Converging and diverging focal lengths in 200mm, 300mm and 500mm OPTICALLY WORKED GLASS Made of high quality, optically worked glass. Highly polished with ground edges GREAT FOR PHYSICS CLASSROOMS This optically true lens set is excellent for physics classroom demonstrations in optics and light refraction Set of Six Optically True Concave & Convex Lenses