Conduction occurs when you set a pan containing food right on a heating element. An egg cooking in a hot frying pan is a good example of conduction at work. This method is the most efficient single way of using electric heat for cooking.
Convection Depends on Air
Convection warms food in pans that are not actually touching the heating element. It uses the hot air around the element to carry heat to the pan.
Your oven in your range works by convection. Most houses are warmed in winter in the same way. The heat produced in a furnace warms the air as it circulates through. This air in turn keeps your body warm.
Radiation is Like the Sun
Radiation heating is more difficult to explain. It results when heat or energy waves strike an object and are converted into heat. The energy we receive from the sun is a good example. When you are wearing dark clothes on a chilly day, you may become uncomfortably hot. The sunshine warms you even though the air around you has not been heated. Radiant energy has a way of being absorbed by dark objects and reflected by light colored or shiny surfaces. Did you ever notice how snow melts faster on a black top road than it does on a concrete road?
The electric heat lamp is one of the most familiar sources of radiant heat. Other examples are panels and cables that are built into the walls and ceilings of homes to provide heat.