 Instru ctio n M anu al012-11233AReplacement Gravity BallsAP-8219800-772-8700 www.pasco.com*012-11233*IntroductionThe AP-8219 Replacement Gravity Balls set isdesigned to replace the large lead masses in theAP-8215 Gravitational Torsion Balance.The Replacement Gravity Balls set consists of twolarge tungsten spheres (1.5 kilogram each), and twoadapter rings. The rings allow the tungsten spheresto rest on the Large Mass Swivel Support of theGravitational Torsion Balance (see Figure 1).The tungsten Large Mass has a radius of 27.6 milli-meters. This value is used in the calculation of G,the universal gravitational constant.AssemblyPlace an Adapter Ring into the hole at one end ofthe Large Mass Swivel Support on the GravitationalTorsion Balance. Repeat for the other adapter ring.Carefully place the Large Masses onto the AdapterRings on both ends of the Large Mass Swivel Sup-port.The Adapter Ring allows the center of mass of theLarge Mass to be in alignment with the center ofmass of the Small Mass that is inside the Gravita-tional Torsion Balance case.Adapter ringsTungsten spheresIncluded:Large Mass, Gravitational Torsion Balance (2)Adapter Ring (2)Required: ModelGravitational Torsion Balance AP-8215Attach toEarth Ground.GRAVITATIONALTORSION BALANCEAP-8215Large MassAdapter RingLarge MassSwivel SupportGravitationalTorsion BalanceFigure 1: Large Mass and Adapter RIng

PASCO AP-8219 Instruction Manual