Electrostatic Friction Rod Kit, includes: -3 fabric cloths (wool, cotton, silk) -3 rods (glass, ebonite, lucite), provides the necessary tools to free both positive and negative charges for exploration into electrostatic forces, 0.4 lbs, 9.8x6.0x1.8in
Double Convex Lens, Highly polished, optically true lens is excellent for physics classroom demonstrations in optics and light refraction, with ground edges, great for physics classrooms, with highest grade, Size: 250 mm focal length, Lens measures 1.5in diameter, 0.2 weight