#Physics - How does an induction stove top work?

Question

I just bought an induction stove top. I don't understand how it works! The pot gets hot but the stove top doesn't?

Answer

The cook top emits a magnetic field which excites the atoms of the pot and heats them up.

Analysis

There are a few ways we can make something (like a cooking pot) get hot:

• Conduction - When we use an electric stove (the ones that have the coil of metal that gets hot and the pot gets set on top of), there is a direct transfer of heat from the metal coil to the pot. This is conduction.
• Convection - When a stove, whether electric or gas, heats the air around it and then that hot air heats up the pot, that's convection.

And then there are less practical ways:

• Friction - When you rub your hands together long enough and hard enough, they'll heat up. And so if we were to rub the pot long enough and hard enough, it'll heat up. One of the downsides is that to achieve cooking temperatures, whatever it is that we're rubbing the pan with (our hands perhaps), it'll be at the cooking temperature too for however long we're cooking. Since that isn't practical at all, we have some other methods.
• Radiation - A nuclear reactor gets hot because the fuel (often uranium) experiences nuclear fission - in other words it releases energy as the uranium atoms break into smaller and smaller atoms. A pot could be bombarded with charged particles, say for instance at your local nuclear reactor, and heat it up.

To Induction. Induction uses a magnetic field in the cook top to excite the atoms in the pot. The pot has to be able to conduct electricity, which is why only certain types of cookware will work with the stovetop. For instance, stainless steel and cast iron will work but copper and aluminum won't).

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Questions and comments always welcome!