Materials List: Build a Charge Detector

Each student needs:

  • a square of aluminum foil (about 10 cm by 10 cm)
  • a wide-mouth glass or plastic jar (ask students to bring from home)
  • thin cardboard, larger than the jar opening (ask students to bring cereal boxes from home)
  • silver foil from a candy bar (ask students to bring from home)
  • a pair of scissors
  • a balloon
  • rigid, bare wire (10-15 cm) or unbend a paper clip
  • scotch tape
  • pairs of items, such as wool and nylon, from the Triboelectric Series Reference Sheet (see Figure 1)
  • Charge Detector Graphing Worksheet (optional math component)

For the entire class to use:

  • few cups or bowls of warm water for soaking candy bar wrappers that have a paper backing
  • a few pieces of wool (available at fabric stores)
  • a few large sewing needles (to poke holes into the cardboard)
  • small pliers (may be necessary to bend the wire)
  • a few bar magnets (optional, for the activity introduction)

A table lists 15 objects (silicone rubber to steel to glass) ranked from negative to positive; each object is described as either a conductor or an insulator.
Figure 1. A Chart of Triboelectric Series — a ranking of materials' ability to hold or give up electrons. This list includes both conductors and insulators.
Copyright © Xochitl Zamora Thompson, ITL Program and Laboratory, University of Colorado at Boulder, 2002.