®
I n s t r u c t i o n M a n u a l
0 12 - 1 12 3 3 A
Replacement Gravity Balls
AP-8219
800-772-8700
www.pasco.com
*012-11233*
Introduction
The AP-8219 Replacement Gravity Balls set is
designed to replace the large lead masses in the
AP-8215 Gravitational Torsion Balance.
The Replacement Gravity Balls set consists of two
large tungsten spheres (1.5 kilogram each), and two
adapter rings. The rings allow the tungsten spheres
to rest on the Large Mass Swivel Support of the
Gravitational 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.
Assembly
Place an Adapter Ring into the hole at one end of
the Large Mass Swivel Support on the Gravitational
Torsion Balance. Repeat for the other adapter ring.
Carefully place the Large Masses onto the Adapter
Rings on both ends of the Large Mass Swivel Sup-
port.
The Adapter Ring allows the center of mass of the
Large Mass to be in alignment with the center of
mass of the Small Mass that is inside the Gravita-
tional Torsion Balance case.
Adapter rings
Tungsten spheres
Included:
Large Mass, Gravitational Torsion Balance (2)
Adapter Ring (2)
Required:
Model
Gravitational Torsion Balance
AP-8215
Att
a
ch to
E
a
rth
Gro
u
nd.
GRA
VIT
ATIONAL
TORSION B
ALANCE
AP
-
8
21
5
Large Mass
Adapter Ring
Large Mass
Swivel Support
Gravitational
Torsion Balance
Figure 1: Large Mass and Adapter RIng