switch-zoomMake yourself a grab bag of fun things to test: copper pieces (nails or pipe pieces), zinc washers, pipe cleaners, Mylar, aluminum foil, pennies, nickels, keys, film canisters, paper clips, load stones (magnetic rock), other rocks, and just about anything else in the back of your desk drawer.


Certain materials conduct electricity better than others. Silver, for example, is one of the best electrical conductors on the planet, followed closely by copper and gold. Most scientists use gold contacts because, unlike silver and copper, gold does not tarnish (oxidize) as easily. Gold is a soft metal and wears away much more easily than others, but since most circuits are built for the short term (less than 50 years of use), the loss of material is unnoticeable.
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Modify your basic LED circuit into a Conductivity Circuit by removing one clip lead from the battery and inserting a third clip lead to the battery terminal. The two free ends are your new clips to put things in from the grab bag. Try zippers, metal buttons, barrettes, water from a fountain, the fountain itself, bike racks, locks, doorknobs, unpainted benches… you get the idea!


Here’s what you need:


  • 2 AA batteries
  • AA battery case
  • 3 alligator wires
  • LEDs (any you choose is fine)
  • paper clip
  • penny
  • other metal objects around your house (zippers, chairs, etc…)


Why does metal conduct electricity?

Why does metal, not plastic, conduct electricity? Imagine you have a garden hose with water flowing through it. The hose is like the metal wire, and the water is like the electric current. Trying to run electricity through plastic is like filling your hose with cement. It’s just the nature of the material.



 


Download Student Worksheet & Exercises


Exercises


  1.       Name six materials that are electrically conductive.
  2.        What kinds of materials are conductors and insulators?
  3.      Can you convert an insulator into a conductor? How?
  4.        Name four instances when insulators are a bad idea to have around.
  5.      When are insulators essential to have?

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