A negatively-charged amber rod is brought close to the knob of a leaf electroscope. Positive charge is induced in the knob and negative charge in the leaves of the electroscope. grounding the knob of the electroscope leaves a net positive charge on it. This can be shown by approaching the electroscope with the negative amber rod. This demonstration can also be done with a Braun Electroscope.
Location: Room 4-309B, Shelf A4