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Redistributing charge through contact

Walk across a carpet in dry weather and touch a metal doorknob, and a tiny spark jumps from your finger. Rubbing two materials together does not create electricity from nothing; instead, contact transfers electrons from one surface to the other, leaving one positively charged and the other negatively charged.

3–5 min

Questions you could explore

  • How can transferring electrons leave one material positive and the other negative?
  • What does charge conservation require of the pair?

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