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Purpose To demonstrate the effect of static electricity.
Materials comb aluminum foil scissors
Procedure
Cut ten tiny pieces of aluminum foil and lay them on a table.
Quickly move the comb through your hair. Your hair must be clean, dry, and oil-free.
Hold the teeth of the comb above the foil pieces. Do not touch the aluminum.
Results The aluminum foil pieces move toward the comb. The metal actually moves through the air to reach the comb.
Why? Aluminum foil is made of atoms, which are composed of positive parts called protons and negative parts called electrons. The protons are in the center of the atom (the nucleus) and the electrons spin around the outside of the nucleus. The comb rubs electrons off your hair and becomes negatively charged. As the comb approaches the metal pieces, the negative electrons in the metal move away from the comb, leaving more positive charges on the surface of the metal. Like charges repel each other and unlike charges attract. The attraction between the negatively charged comb and the positive area on the metal is strong enough to overcome the downward pull of gravity, and the metal pieces move through the air to stick to the comb.
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