Gas versus Electric

• Gas ovens and stoves work by burning natural gas. When the gas is turned on, an electric igniter creates sparks until the gas catches on fire. The spent gas flows out of a tube from the back of the oven to the outdoors. An electric oven uses electric elements called resistors. When electricity flows through a resistor, the electric energy is turned into heat energy. This causes the resistor to heat up, providing the energy to heat the food.
  
  

Transferring the Heat

• The heat on the stove top flows directly into the bottom of the pan through conduction, but the situation is different inside the oven. The burners or electric elements make heat, but they can't distribute that heat directly to the food. Some of it shines out as infrared radiation, which is absorbed by the food, but the rest of it has to be conducted by the air to the food. Since air doesn't conduct heat very well, this can be a slow process.
  
  To speed things up, convection ovens incorporate a fan. This fan circulates the air inside, bringing the heat to the food more efficiently and cooking the meal more quickly.
  
  

Novel Heating Techniques

• Quartz halogen cook tops work in a manner quite different than other electronic heating technologies. The hot halogen element is insulated within quartz crystal. The halogen heats to an extremely high temperature very quickly, but heat doesn't come out of it. Instead, infrared heat radiation flows out. Infrared radiation is released by nearly everything in the universe, and is capable of heating solid objects it comes into contact with. When the high-intensity infrared radiation comes into contact with the bottom of a pan, it heats up the pan, cooking the food within.
  
  Even stranger are magnetic induction burners. These produce a high-frequency electro-magnetic signal that creates a rapidly switching electric current in metal pans placed on top of the burners. Because the electric current flips directions so fast, it creates a lot of resistance in the pan, which causes the pan to heat up.