10 Examples of Electrical Conductors and Insulators

Things That Don't Conduct Electricity and Things That Do

Illustration depicting examples of 5 electrical conductors and 5 electrical insulators


Do you know how electrical conductors and insulators work? In case you don't, let's review just what conductors and insulators are.

Conductors vs. Insulators

Simply put, electrical conductors are materials that conduct electricity, while insulators do not. How does that work? Whether a substance conducts electricity depends on how easily electrons can move through it. For example, protons don't move because, while they would carry an electrical charge, they are bound to other protons and neutrons in atomic nuclei. Valence electrons are like outer planets orbiting a star. They're attracted enough to stay in position, but it doesn't always take a lot of energy to knock them out of place. Metals readily lose and gain electrons, so they top the list of conductors.

Organic molecules are mostly insulators, in part because they're held together by covalent (shared electron) bonds and also because hydrogen bonding helps stabilize many molecules. Most materials are neither good conductors nor good insulators. They don't readily conduct, but if enough energy is supplied, the electrons will move.

Some materials in pure form are insulators but will conduct if they are doped with small quantities of another element or if they contain impurities. For example, most ceramics are excellent insulators, but if you dope them, you can create a superconductor. Pure water is an insulator, while dirty water conducts weakly and saltwater—with its free-floating ions—conducts well.

10 Electrical Conductors

The best electrical conductor, under conditions of ordinary temperature and pressure, is the metallic element silver. It's not always an ideal choice as a material, however, due to its cost and because it tarnishes. The oxide layer known as tarnish is not conductive. Similarly, rust, verdigris, and other oxide layers reduce conductivity. The following are examples of effective electrical conductors:

  1. Silver
  2. Gold
  3. Copper
  4. Aluminum
  5. Mercury
  6. Steel
  7. Iron
  8. Seawater
  9. Concrete
  10. Mercury

More conductors:

  • Platinum
  • Brass
  • Bronze
  • Graphite
  • Dirty water
  • Lemon juice

10 Electrical Insulators

  1. Rubber
  2. Glass
  3. Pure water
  4. Oil
  5. Air
  6. Diamond
  7. Dry wood
  8. Dry cotton
  9. Plastic
  10. Asphalt

More insulators:

  • Fiberglass
  • Dry paper
  • Porcelain
  • Ceramics
  • Quartz

Other Factors That Influence Conductivity

It's worth noting the shape and size of a material affect its conductivity. For example, a thick piece of matter will conduct better than a thin piece of the same size and length. If you take two pieces of a material of the same thickness, but one is shorter than the other, the shorter one will conduct better. This is because the shorter piece has less resistance, in much the same way that it's easier to force water through a short pipe than a long one.

Temperature also affects conductivity. As temperature increases, atoms and their electrons gain energy. Some insulators (e.g., glass) are poor conductors when cool, yet good conductors when hot. Most metals are better conductors when cool and less efficient conductors when hot. Some good conductors become superconductors at extremely low temperatures.

Although electrons flow through a conductive material, they don't damage the atoms or cause wear, as would the friction of water in a canyon, for example. Moving electrons do experience resistance or cause friction, however. The flow of electrical current can lead to the heating of a conductive material.