The Technology of Induction Cooktops
At its simplest, an electrical current in the cooktop is used to produce a magnetic field. Placing the pan on the cooktop in the magnetic field induces a circulating electrical current in the base of the pan. The resistance to this current causes the pan to heat up. This system is a more efficient transfer of energy than a gas flame or heated electrical element and so boiling a pan of water, for example, is much quicker. This does not necessarily mean that there are great energy savings.
Is this safe?
To put our minds at rest, let us think of a few things that might go wrong...maybe leaving a small, magnetic piece of metal on the cooktop? Each manufacturer I have looked at has a minimum pan detection size feature - the cooktop burner will not operate unless there is at least a four inch diameter (or similar) pan on the cooktop. How about trying to stir a pot of soup with a spoon made of something metalic? Will it get hot? Will my hand get pulled down to the surface of the cooktop? Again I rely on the manufacturers statements as well as reviews by people who have used the induciotn cooktops. The magnetic field is only induced in the thin slice just above the cooktop where the base of the pan is. The pan gets hot, this heats its contents but not your favorite stirring spoon. What about my iron jewelry? Same as the spoon in the previous example. No, as far as I knwo, you will not be dragged to the cooktop by magnetism and cooked by your jewelry.
I will not and cannot categorically state that it is safe - I am not a scientist or expert in the subject but I will say this: From everything I have read during the course of my research the manufacturers SEEM to have the safety aspect covered. Personally I would quite happily get an induction cooktop. As I said I am no scientist but I understand enough basic physics not to be worried by this technology.