As an expert in the field of material science with a focus on electrical properties, I can provide a comprehensive answer to your question regarding the electrical conductivity of air.

Air, which is primarily composed of nitrogen (about 78%) and oxygen (about 21%) along with trace amounts of other gases, is generally considered to be an insulator. This means that under normal conditions, air does not allow electricity to pass through it easily. The reason for this is that air is a non-polar molecule and does not have free electrons that can move and carry an electric charge, which is a characteristic of conductors.

However, it's important to note that the insulating properties of air can be influenced by several factors. For instance, humidity can significantly impact air's ability to act as an insulator. Moist air can conduct electricity better than dry air because water vapor is a polar molecule and can facilitate the movement of ions. This is why high humidity can lead to increased electrical conductivity in the air.

Another factor that can affect air's electrical properties is the presence of impurities or contaminants. For example, air that is polluted with particulates or chemicals can have altered electrical properties. In some cases, these impurities can increase the conductivity of air, although this is not a common scenario.

Now, let's discuss the phenomenon of dielectric breakdown. Dielectric breakdown occurs when the electric field strength exceeds the dielectric strength of a material. In the case of air, this means that if the voltage is high enough, the insulating properties of air can be overcome, and air can become a conductor. This is what happens during a lightning strike, where the electric field in a thundercloud becomes strong enough to ionize the surrounding air, creating a conductive path for the electrical discharge.

It's also worth mentioning that air can be a conductor of heat. Heat can be transferred through air via three primary mechanisms: conduction, convection, and radiation. While air is a relatively poor conductor of heat compared to metals, it can still transfer heat, albeit less efficiently.

In summary, under normal conditions, air is an insulator and does not conduct electricity well. However, its insulating properties can be compromised by factors such as humidity and impurities. At very high voltages, air can undergo dielectric breakdown and become a conductor. Additionally, air can conduct heat, albeit not as efficiently as metals.

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Air is certainly not a conductor of electricity (or heat) in the sense metals are. In fact, dry air is a good dielectric (insulator.) At very high voltages, there is dielectric breakdown, and we have sparks and conduction through air.read more >>