Replacement Pith Balls for Electroscope, 10-Pack Subcategory_Pressure and Gas Laws and aluminum at a shared

and aluminum at a shared 0

Manually-operated seismograph model that traces shock waves onto a pulled paper strip

and 4-pole armature configurations on the same motor frame by swapping interchangeable enameled-copper armatures past a permanent bar magnet on a disc commutator

Optically-worked glass double convex lens with a 150mm focal length and 1

Replacement Pith Balls for Electroscope, 10-Pack Subcategory_Pressure and Gas Laws and aluminum at a sharedSpare pack of ten low mass pith balls sized for the standard pith ball electroscope, supplying replacements when the originals lose loft or split during repeated charging cycles.