Which materials are examples of insulators?

Which materials are examples of insulators?

• A. Glass, Plastic, Wood, Most non-metals
• B. Copper, Silver, Gold
• C. Water, Salt
• D. Air and Water

Answer: (A)

Insulators resist the flow of electricity because their electrons are tightly bound and not free to move. Glass, plastic and wood are classic insulators, so they do not allow charge to pass easily. Most non-metals behave like this too, having high resistance to current. In contrast, metals such as copper, silver and gold have free electrons that move easily, making them good conductors rather than insulators. Water conducts electricity when it contains ions (from impurities or dissolved salt); pure water is only a weak conductor, but it’s not a reliable insulator. Air is a very good insulator, but because water isn’t, a choice that pairs air with water isn’t purely insulative. So the materials that are insulators are glass, plastic, wood, and most non-metals.

Insulators resist the flow of electricity because their electrons are tightly bound and not free to move. Glass, plastic and wood are classic insulators, so they do not allow charge to pass easily. Most non-metals behave like this too, having high resistance to current.

In contrast, metals such as copper, silver and gold have free electrons that move easily, making them good conductors rather than insulators. Water conducts electricity when it contains ions (from impurities or dissolved salt); pure water is only a weak conductor, but it’s not a reliable insulator. Air is a very good insulator, but because water isn’t, a choice that pairs air with water isn’t purely insulative.

So the materials that are insulators are glass, plastic, wood, and most non-metals.