Gravesande Ring and Ball Apparatus Type_Apron housed in a vinyl-covered zinc

housed in a vinyl-covered zinc steel case with a fold-out winding handle for field work

and lead threading onto string or rod for mass-dependent pendulum period comparisons

tracing hot-air flow between the twin flues

Two-ohm wire-wound fixed resistor in an ABS module with 4mm sockets

this replacement key matches the goggle sanitizer cabinet lock for classroom stockroom maintenance

Gravesande Ring and Ball Apparatus Type_Apron housed in a vinyl-covered zincCaptive 19mm brass ball on a rod mounted Gravesande ring, passing freely through the ring at room temperature but halted by the ring after flame heating expands the metal.