Opisometer Geology this concave glass mirror at

this concave glass mirror at 100mm focal length runs at f/1 for vivid real-image demos and converging-reflection work

and field magnet for direct observation as students trace how current produces rotation in a closed magnetic circuit

Polished hardwood test tube rack with a traditional two-tier design

Relay-based NAND-gate module on a demonstration base

and cochlear detail for auditory teaching

Opisometer Geology this concave glass mirror atOpisometer with a knurled wheel on a threaded spindle, rolling along curved lines on maps, charts, and drawings to convert winding distance into straight line length for geography coursework.