Traditional cookers, such as gas burning ones or electrical coils, use heat transfer to heat the pots and pans on the stove, and thus your food.
Induction heaters are a little different. They use induction heating to directly heat the cooking vessel itself. To work the cooking vessel needs to be made out of ferromagnetic metal. If the cooking vessel isn’t constructed of ferromagnetic metal then an interface disc can be used.
An induction cooker has a coil of copper wire under the cooking platform. By passing an alternating electric current through the coil, an oscillating magnetic field is produced. The magnetic field induces an electric current in the cooking pot. The electric current combined with the resistance of the pot creates heat, which is used to heat the food. Although the current is high to create the necessary heat, the voltage is low to keep it safe.
So that’s the science; now what are the advantages I hear you cry? If you let me finish, I will tell you.
In comparison to traditional electric cookers, induction cookers are more energy-efficient and faster. It also has the advantages that gas cookers have, as you can control the heating energy instantaneously. As it is only the cooking vessel that is heated, no energy is wasted, unlike electrical heaters that heat their elements constantly and require time to heat up and cool down. Again due to this method of heating the pot directly, no heat energy is loss to the surrounds.
If you have children or clumsy hands around your kitchen, then an induction cooker is useful as it is much safer to use (in terms of accidental burning). Because it only heats the pot you are safe from accidentally burning yourself on an exposed surface. Traditional electric cookers can be dangerous in this regard because the surface can remain hot long after the cooker has been turned off, posing the risk of accidental burning.
Most any cookware can be used with an induction cooker, especially if you have an interface disc for use with non-ferromagnetic cookware. Some cookware will be marked with labels to show its compatibility with electric, gas and induction cookers. As a general rule of thumb, induction cookers will work great with any pot/pan that has a high ferrous metal content in its base. So for example, cast iron pans will work great without an issues.
Stainless steel pans will work well if the stainless steel is magnetic grade stainless steel. Basically if a magnet sticks to the pan, you’re in luck. There are a limited number of ‘all-metal’ induction cookers that will work with all metals, but at a lower efficiency.