Double Concave Glass Lens, 50mm Diameter, 100mm Focal Length, 8mm Thick Geology supporting variable audio modulation 1Hz-1kHz

supporting variable audio modulation 1Hz-1kHz plus a 250kHz square wave for speed-of-light measurement work

producing oxygen's characteristic emission lines for spectroscope viewing of atomic-emission and quantum-energy levels

producing a spread of spring constants for Hooke's-Law and mass-spring comparison work in introductory mechanics

Two-hundred-fifty-gram push-pull balance in an acrylic tubular body

Double Concave Glass Lens, 50mm Diameter, 100mm Focal Length, 8mm Thick Geology supporting variable audio modulation 1Hz-1kHzGlass double concave lens at 50mm diameter and 100mm focal length, an 8mm thick blank delivering the same diverging behavior at lower mass for ray box and small mount setups.