Differences between revisions 8 and 9
Revision 8 as of 2008-06-19 16:09:06
Size: 1016
Editor: reardon
Revision 9 as of 2013-07-12 18:17:53
Size: 994
Editor: localhost
Comment: converted to 1.6 markup
Deletions are marked like this. Additions are marked like this.
Line 4: Line 4:
Located in [:ElectrostaticsCabinet:Electrostatics Cabinet], A1 Located in [[ElectrostaticsCabinet|Electrostatics Cabinet]], A1
Line 18: Line 18:
attachment:TwoPithBalls5A2020.jpg {{attachment:TwoPithBalls5A2020.jpg}}
Line 21: Line 21:
[:Electrostatics:Electrostatics] [[Electrostatics]]
Line 23: Line 23:
[:Demonstrations:Demonstrations] [[Demonstrations]]
Line 25: Line 25:
[:Instructional:Home] [[Instructional|Home]]

Two Pith Balls 5A20.20

Located in Electrostatics Cabinet, A1

Rub rod with cat fur to charge rod.

Bring rod near two pith balls (pith balls hang from insulating thread).

At first balls are attracted to rod.

When they touch, charge transfers. Now they are repelled by rod, and by each other.

Pith Ball Pitfalls:

Pith balls act as imperfectly conducting spheres. Charge on the surface may or may not be free to move. Balls may stick together even though they have net charges of similar sign, due to induced charge distribution (a fascinating problem in electrostatics beyond the scope of an undergraduate course). Gently tapping, or blowing on, the pith balls may be enough for them to separate, so that induced charge effects become insignificant.





fw: TwoPithBalls (last edited 2013-07-12 18:17:53 by localhost)