Try this at home!

Charged comb attracting a coke can

St. Mary's H.S. Physics YouTube Channel

School blocks YouTube? Use the file below.





Grounded, neutral objects
gain or lose electrons by induction.



Case III - Negative rod/neutral object

[ Flash ]


Electrons are repelled down into the ground. Object becomes positive





Case IV - Positive rod / neutral object


[ Flash ]



Neutral object becomes negative as electrons are drawn up from the ground





Case V – Induction w/ grounded electroscope

St. Mary's Physics YouTube Channel



1. A negative rod is brought near,
top touched, finger removed, rod removed.

2. A negative rod is brought near,
top touched, rod removed, finger removed.






Electroscope grounded







When Ground Removed,
Electroscope Maintains Charge 


Electroscope Charge?






Electrons left Electroscope




What would the charge on the the electroscope be if a positive rod were used?









(with grounding)
Rod Makes Electroscope
- +
+ -




Rod Makes Electroscope
- -
+ +







©Tony Mangiacapre., - All Rights Reserved [Home]

Established 1995

Use any material on this site (w/ attribution)