PASCO EM-8661-220V Ring Launcher - Manual (Page 3)

R i n g L a u n c h e r E M - 8 6 6 1 - 2 2 0 V
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Using the Induction Bulb (part of the optional
EM-8662 Ring Launcher Accessory)
The Induction Bulb in the optional EM-8662 Ring Launcher
Accessory allows you to show how voltage induced from the
copper coil on the launcher can light the bulb.
Hold the plastic base of the induction bulb over the iron rod so
that the copper coil on the plastic base is near the copper coil on
the Ring Launcher. While holding the induction bulb near the
copper coil, use the other hand to briefly hold down the Launch
Switch.
• The small light bulb will light up..
Background
The alternating current (AC) power source generates an alternat-
ing current in the copper coil of the launcher. The changing cur-
rent induces an alternating electromagnetic field. When a
conducting ring is on the Ring Launcher, the alternating electro-
magnetic field induces a current in the ring. The current in the
ring generates another electromagnetic field, opposed to the one
generated by the launcher. The magnetic repulsion between the
two fields pushes the ring upward.
Closed metal rings are conductors of electricity, and therefore
respond to the changing electromagnetic field. In the Split Alu-
minum Ring (part of the optional EM-8662 Ring Launcher
Accessory), the ring cannot conduct an electric current. The cir-
cuit is “open”. Without current, no electromagnetic repulsion
occurs, and the split aluminum ring is not pushed upward.
Experimental Variations and Notes
If desired, you can place the Ring Launcher in a horizontal or
angular launching position. Use the Rod Clamp on the back of
the launcher to mount the launcher on a support rod.
To show how the properties of the iron rod enhance the electro-
magnetic repulsion, attempt to launch a ring with the iron rod
removed. You will notice that the height of the launched ring is
about one half of the height reached when the iron rod is inserted
into the copper coil.
Try launching multiple rings simultaneously. The experimental
model changes, challenging students to think more deeply about
the concepts. The inductive effects occur within the closed rings,
and all other rings are pushed up by the induced rings.
Credit to the Originators of the Classroom
“Jumping Ring”
The PASCO EM-8661 Ring Launcher is modeled after the class-
room “jumping ring” designed by Carl S. Schneider and John P.
Ertel, Physics Department, United States Naval Academy,
Annapolis, Maryland, USA.
An article describing their design is available in the American
Journal of Physics, 66 (8), August 1998, pages 686 to 692.
Induction Bulb with the Ring Launcher
Copper
Coil
Induction
Bulb
Launch
Switch