Gas stoves are usually fueled by an external natural gas line that's connected to the stove by a series of pipes. These natural gas lines run underground and into the home. The gas in these lines is pressurized. When the stove is turned on, the gas line is unblocked and the fuel is allowed to flow into the stove's pipes and toward the burner. When the gas reaches a certain point in the stove's pipes, it mixes with air. This air is what allows the stove to produce a blue, easily controlled flame.
Fueling the Stove
Igniting the Fuel
After the natural gas mixes with air, it continues on its journey toward the burner. Along the way, a smaller pipe branches off of the main stove pipe. This smaller pipe leads to the ignition source in the stove. In older stoves, this ignition source is a pilot light, which is a small gas-fueled flame that remains lit at all times. In newer gas stoves, the ignition source is an electric spark igniter, which produces the clicking sound heard when the stove burner is set to "light."
Heading to the Burner
The ignition source lights the gas in the smaller pipe. This flaming gas travels back down the smaller pipe to the main pipe, igniting the gas there. The flame in the main gas pipe travels to the burner, where it's emitted through the holes around the burner base. When the flame is adjusted using the controls on the stove, the amount of gas allowed into the main pipe changes, varying the height and strength of the flame.