Why No Perfect Insulators? Exploring Electrical Resistance

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In summary, the conversation discusses the concept of perfect insulators and why they do not exist in practice. The individual asking the question is surprised by this idea, as they believed materials like plastic and wood completely resisted the flow of electricity. However, it is explained that at high enough voltages, even these materials can become conductors. The conversation also mentions the phenomenon of electrical breakdown and provides a link for further information.
  • #1
RobinSky
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I just some how fell into a wiki article about http://en.wikipedia.org/wiki/Insulator_%28electrical%29" and then read the following statement:

A true insulator is a material that does not respond to an electric field and completely resists the flow of electric charge. In practice, however, perfect insulators do not exist.

The question is, why is it that there are no perfect insulators? I thought things like plast, wood, didn't allow electricity to flow through at all, but of course physics does it again, turns your head completely upside down! :rolleyes:

Could anyone explain this? I tried to google it but didn't find anything relevant.
 
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  • #2
For one thing valence electrons eventually break loose at high enough voltages...that is, the medium becomes a conductor.

A simple example is how a spark plug or lightning ionizes air which is a pretty good insulator (it must be since I don't get shocked sitting here at my computer with 120 volt ac nearby!)

Check here for some interesting background:

http://en.wikipedia.org/wiki/Electrical_breakdown

Some interesting photographs...
 
  • #3
Ahha! I had no idea, thanks for the reply! :)
 

1. Why can't we find a perfect insulator?

There is no such thing as a perfect insulator because all materials have some level of electrical resistance. Even materials that are considered "good" insulators, such as rubber or glass, still have some level of resistance to electrical current.

2. What causes electrical resistance in insulators?

Electrical resistance in insulators is caused by the movement of electrons. In insulating materials, the electrons are tightly bound to their atoms and are not able to move freely, which creates resistance to the flow of electricity.

3. Can insulators be made more resistant?

Yes, insulators can be made more resistant by using materials with higher resistivity, such as ceramics or polymers. Additionally, the thickness of the insulating material can also affect its resistance, with thicker materials typically having higher resistance.

4. Why is electrical resistance important in insulators?

Electrical resistance in insulators is important because it helps to prevent the flow of electricity. This is essential for safety reasons, as it helps to prevent electrical shocks and fires. Insulators also play a crucial role in electronic devices by controlling the flow of electricity and preventing short circuits.

5. Are there any materials that have zero resistance?

Yes, there are some materials that have zero resistance, known as superconductors. These materials have the ability to conduct electricity without any loss of energy due to resistance. However, superconductors only exhibit this behavior at very low temperatures, making them impractical for everyday use.

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