Clicked Gallery

Conductor vs insulator: what's the difference?

Highlighted from a real textbook passage. Explained by Clicked.

Used in a sentence

University Course Reader · STEM

The wire's copper core is a conductor, and the plastic around it is an insulator that stops the current reaching your hand.

The reader highlighted one word in a textbook passage. Clicked broke down the physics term “conductor” into plain English:

Explained in three depths

Same facts, different vibe — Slang mode 😎

The Clicked way

●○○

Overview

A conductor is a material that lets electricity or heat pass through it easily, and an insulator is a material that resists them. Copper conducts and plastic insulates, which is why a wire is copper inside and plastic outside. In a metal, some electrons are free to move through it, and they carry electricity and heat. In an insulator, every electron is held to its own atom, so nothing moves. Free electrons make a conductor, held electrons an insulator.
●○○

Overview

A conductor lets electricity or heat travel through it, and an insulator gets in the way. What sets them apart is loose electrons. Metals have electrons that are free to roam through the material, and those roaming electrons carry current and heat along. Insulators keep every electron pinned to its atom, so nothing gets carried. If the electrons can roam, the material conducts; if they are pinned, it insulates. 😎

A quick take — often all you need.

●●○

Detail

A conductor is a material that lets electricity or heat pass through it easily, and an insulator is a material that resists them. What separates the two is what the electrons in the material are free to do. In a metal such as copper, some electrons are not attached to any one atom and can wander through the whole piece. Connect a battery across it and the loose electrons drift towards the battery's positive end, and that drift is an electric current. In an insulator such as rubber, every electron is held to its atom. Connect a battery across it and every electron stays where it is, so no current flows. The same loose electrons carry heat as well. Put a metal spoon in hot tea and the handle is warm within a minute, because the free electrons pass the energy along the length of it. A wooden spoon in the same tea warms only slowly, and mostly near the wet end. That is why the metals that conduct electricity well also conduct heat well, and why oven gloves and saucepan handles are made of insulators.
●●○

Detail

A conductor lets electricity or heat travel through it, an insulator gets in the way, and the difference is whether the electrons inside can move. Metals have some electrons that are not tied to a particular atom, and those loose electrons carry current and heat wherever the metal goes. In plastic, glass and wood every electron is tied down, so nothing gets carried. That is why a metal gate on a frosty morning feels far colder than the wooden fence beside it, though both are at the same temperature. The gate is no colder; it is better at taking heat out of your hand, because its loose electrons whisk the warmth away, and the wood has no loose electrons to do the same. Touch the metal side of a hot kettle and the same thing happens the other way round, which is why the handle is plastic. Every phone charger and extension cord is that pairing in one object: a copper core to carry the current, wrapped in an insulator so the current stays in the core and away from your hand. The test is loose electrons or none. 😎

Want more? One click digs deeper.

●●●

Analogy

A conductor is a town with a working postal service, and an insulator is a town where the postal workers cannot leave their desks. In the first town, post a letter at one end and it reaches the other, because the workers are free to move and hand it along. In the second, post the letter and it stays in the box. The letters are the energy, electrical or heat, that a material carries. The workers who are free to move are the free electrons of a metal, and the workers stuck at their desks are the electrons that an insulator holds to their atoms. Whether anything gets through depends on whether there is anyone free to carry it, and the same is true of a material and its electrons.
Deepest level reached.
●●●

Analogy

A conductor is an open-plan office, and an insulator is an office where every door is shut. Start a rumour at one end of the open-plan floor and it is at the other end in ten minutes, because people wander from desk to desk and pass it on. Start the same rumour in the office of shut doors and it stays with the person who heard it. The rumour stands for the energy; wandering staff stand for a metal's free electrons; staff behind shut doors stand for the electrons an insulator holds in place. A rumour goes only as far as someone is free to take it, and current and heat go through a material only as far as its electrons can move. 😎
Deepest level reached.

Unfamiliar concept? A real-world example makes it click — fresh analogies on tap.

AI explanations may contain errors · Not professional advice

Formal definition — The same term, explained the usual way

A conductor is a material through which electric charge or heat flows readily, owing to charge carriers, typically free electrons in metals, that can move under an applied electric field or temperature gradient. An insulator is a material in which the electrons are tightly bound, so it presents very high electrical resistance and low thermal conductivity. The distinction is one of degree: conductivity spans more than twenty orders of magnitude between the best metals and the best insulators, and any insulator breaks down and conducts if the applied field is large enough. Semiconductors occupy the intermediate range and can be switched between the two behaviours; a few materials, such as diamond, conduct heat well while insulating electrically.

Want Clicked to explain terms like “conductor” directly in your browser — including on PDFs?

Add to Chrome — Free

50 free Explanations · No credit card required