Investigation: electrostatic attraction and repulsion

Aim: to show that like charges repel and unlike charges attract, and that charging occurs by electron transfer.

• Apparatus: plastic rod, glass rod, silk and wool cloth, suspended pith balls or a retort stand.
• Method: charge each rod by rubbing, then bring it near suspended charged and neutral objects.
• Observation: like charges push apart; unlike charges pull together; neutral objects are attracted by induction.
• Rubbing transfers electrons — it never creates charge.

• Induction — charge separation in a neutral object near a charged one.
• Electron transfer — the mechanism of charging by friction.