Climate - truthful information about climate, related activism and politics.

Thanks for correcting.

There seems to be contradictory information on the subject.

Aluminum foil is proven to melt on induction cookers (see attached photo). But that's because foil is thin.

https://commons.wikimedia.org/wiki/File:Foil_on_induction_cooktop.jpg

A photo I suggest taking a look at: induction heater burning aluminum foil. Taken from the publication "Practical Course on School Experiments for Future Physics teachers".

...as for thick aluminum cookware, or copper cookware, I was not implying that they would overheat themselves, I was implying that the induction cooker would overheat its coil attempting to work with them, because they conduct current better than the coil. But perhaps that's prevented by protection circuits or a process I haven't taken into account. I can't test since I don't have an induction cooker at home.

EM-fields induce current in copper and aluminum perfectly fine, no ferromagnetism is needed. You can build a coreless transformer for example, ordinary tranformers simply benefit from having a core (the core is separated into thin layers to reduce heating). Copper and aluminum simply conduct current very well, so appreciable heat does not appear at everyday levels of field strength and current. Steel and cast iron, having considerable resistance, heat up in a similar field, conducting similar amounts of current. There's a potential gap in my understanding of the process, however - perhaps I'm failing to take into account the frequency of a cooking field in an induction cooker. The frequency determines whether current wants to travel in the depth of the conductor or on the surface of the conductor.

Simple experiments that I can recommend:

• take a circuar magnet and let it drop along a copper pipe -> you will observe that it drops slowly, braking itself by inducing current in copper

• spin a rotor with magnets next to a plate of copper -> you will observe mechanical resistance to spinning, because it induces current in copper

I can also recommend an interesting Wikipedia article: https://en.wikipedia.org/wiki/Eddy_current

Quoting from the article (emphasis mine):

For example, a nearby conductive surface will exert a drag force on a moving magnet that opposes its motion, due to eddy currents induced in the surface by the moving magnetic field. This effect is employed in eddy current brakes which are used to stop rotating power tools quickly when they are turned off. The current flowing through the resistance of the conductor also dissipates energy as heat in the material. Thus eddy currents are a cause of energy loss in alternating current (AC) inductors, transformers, electric motors and generators, and other AC machinery, requiring special construction such as laminated magnetic cores or ferrite cores to minimize them. Eddy currents are also used to heat objects in induction heating furnaces and equipment, and to detect cracks and flaws in metal parts using eddy-current testing instruments.

I also recommend this source and will quote them below:

Induction heating utilizes electromagnetic fields to heat conductive materials without any direct contact. Aluminum, although non-magnetic, heats effectively because of its high electrical conductivity. However, it produces weaker eddy currents in comparison to ferrous metals.