is aluminium foil an insulator?? i review on web that aluminium silver paper is conductor but how?? if we fill a warm food in aluminium foil, it dosent allow the food warmth to escape, i.e., its an insulator.... Yet it is used in electric circuits also.... So is the aluminium silver paper an insulator or a conductor??????- tinkle (age 13)india

If you have actually a cheap Digital Voltmeter (DVM) you have the right to do what I simply did- measure the resistance in between contacts to different parts that a item of aluminum foil. The conducts an extremely well. If there's any insulating polymer or oxide ~ above it, the contact I provided easily broke through the to the conducting aluminum.

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As you say, due to the fact that Alconducts electrical power well it will also conduct heat well. For this reason why doesn't a samosa sheathe in aluminum foil cool under quickly? Think of wherein the foil goes. It just wraps around the samosa, the doesn't reach far from it. So the doesn't have a means to conduct heat much away. The foil doesn't lot helpto insulate the food from being cooled by the air, but it does assist in one more way. One main way that common hot food cools is by evaporating water. The foil keeps the water vapor indigenous escaping quickly, slowing under the evaporation and thus slowing down the cooling.

Mike W.

I think the questioner is mixing up the two definitions of the word conductor, i.e., electrical conductor vs. Warm conductor. Al is an electric conductor, in fact, some wires are made that Al. That non-conductivity the heat, i.e., that insulation is because of two reasons: One is, as Mike W. Said, the tight wrapping of Al around the food stop convective warm transfer, i.e., it stop the flow of hot air from within the silver paper to outside. The various other reason is the Al"s reflective (mirror-like) surface mirrors the radiation (heat) ago to inside. In fact, Al blankets occupational this way. See an are blanket - Wikipedia. Heat also may transport by conduction. In this regard, Al is a good conductor, i.e., a bad insulator of warm -- touch an aluminum home window frame in winter and you will certainly feel cold. As to why a great conductor of electrical power is also a an excellent conductor that heat, see: ((((OR)))) ((((OR)))) Mehran (age 65)Arlington Heights, IL

Hi Mehran- Tinkle was ideal to i think that an excellent electrical conductors are also great heat conductors, as described by the Wiedemann-Franz law. You raise part other good points, though.

Thatsame electric conductivity renders the aluminum highly reflective. As you say, that reduces the loss of heat by electromagnetic radiation. I'd forget to encompass that.

As far as the convection goes, due to the fact that the silver paper gets practically as warm as the food, and air have the right to convect previous the foil, ns don't think the foil reduces that warmth loss much.

Still, in between reducing evaporation and also reducing radiation, the silver paper should assist noticeably.

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Mike W.

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