Publisher: PASCO scientific.
Cited passages: Basic Electrostatics System, instruction manual 012-07227G, printed pp. 4–5 and 14–15, Procedure 1A steps 3–8: handle charge, withdrawal, contact and disk retest; Basic Electrostatics System, instruction manual 012-07227G, printed pp. 9–10, 13–15, Figure 1.1 and Procedure 1A.