and 40,000 cycles per second) The current causes the coil to generate a magnetic field that extends some distance from the coil, and that alternates at the same rate If a pot made from a magnetic material — cast iron, steel, stainless steel of the proper crystal structure (ferritic) — is placed near the coil, then the alternating magnetic field induces an alternating electrical current in the pot That is, it causes electrons to move in the pot, and that movement rapidly generates heat Induction heating has two notable advantages over burners and radiant elements Like microwave heating, it’s more efficient, because all the energy goes into the object to be heated, not into the surrounding air And only the pot and its contents get very hot The ceramic surface above the induction coil is heated only indirectly by the pot, because its electrons aren’t free to be moved by the magnetic field Baking: Air Convection and Radiation When we bake a food, we surround it with a hot enclosure, the oven, and rely on a combination of radiation from the walls and hot-air convection to heat the food Baking easily dehydrates the surface of foods, and so will brown them well provided the oven temperature is high enough Typical baking temperatures are well above the boiling point, from 300 to 500ºF/150–250ºC), and yet baking is nowhere near as efficient a means of heat transfer as is boiling A potato can be boiled in less time than it takes to be baked at a much hotter temperature This is so because neither radiation nor air convection at 500ºF transfers heat very rapidly to food Oven air is less than a thousandth as dense as water, so the collisions between hot molecules and food are much less frequent in the oven than in the ... Baking: Air Convection and Radiation When we bake a food, we surround it with a hot enclosure, the oven, and rely on a combination of radiation from the walls and hot-air convection to heat the food. .. easily dehydrates the surface of foods, and so will brown them well provided the oven temperature is high enough Typical baking temperatures are well above the boiling point, from 300 to 500ºF/150–250ºC), and yet baking... transfers heat very rapidly to food Oven air is less than a thousandth as dense as water, so the collisions between hot molecules and food are much less frequent in the oven than in the