An oven is a thermally insulated chamber used for the heating, toasting, baking, broiling or drying of a substance, and most commonly used for cooking. The source of heat in a conventional oven is stationery and rises up from the bottom.
A convection oven however is an oven that has fans to circulate air around food, using the convection mechanism to cook food faster than a conventional oven. Convection ovens also do not need to preheat like conventional ovens do.
Microwave ovens heat food using microwaves, a form of electromagnetic radiation similar to radio waves. ... The microwaves reflect off the metal interior of the oven and cause the water molecules in food to vibrate. This vibration results in friction between molecules, which produces heat that cooks the food.