Electrostatic Friction Rod Kit, 3 Cloths and 3 Rods Type_Round End Wooden-framed abacus with two steel

Wooden-framed abacus with two steel wires of 20 beads each on a 13

5 inches producing 50-60 dots per second via a vibrating striker

this microphone amplifier connects a microphone input to both an integrated speaker and an oscilloscope-driving amplified signal for waveform study

Electronic Stability Program Module - Item # AT-5202

Polished 8cm brass sphere on an ebonite-insulated metal base

Electrostatic Friction Rod Kit, 3 Cloths and 3 Rods Type_Round End Wooden-framed abacus with two steelElectrostatic friction rod kit pairing wool, cotton, and silk cloths with glass, ebonite, and acrylic rods for triboelectric charge generation experiments in series.