In cooking, a gas stove is a cooker which uses natural gas as a fuel source.
The first gas stoves were developed already in the 1820s, but these remained isolated experiments. (James Sharp patented a gas stove in Northampton, England in 1826 and opened a gas stove factory in 1836.) At the World Fair in London in 1851, a gas stove was shown, but only in the 1880s did this technology start to become a commercial success. The main factor for this delay was the slow growth of the gas pipe network.
The first gas stoves were rather unwieldy, but soon the oven was integrated into the base and the size reduced to fit in better with the rest of the kitchen furniture. In the 1910s, producers started to enamel their gas stoves for easier cleaning. A high-end gas stove called the AGA cooker was invented in 1922 by Swedish Nobel prize winner Gustaf Dalén. It is considered to be the most efficient design and is a much sought after kitchen "must have" in certain circles—despite the hefty price tag.
Gas stoves today use two basic types of ignition sources, standing pilot and electric. A stove with a standing pilot has a small, continuously burning gas flame (called a [pilot flame]) under the cooktop. The flame is between the front and back burners. When the stove is turned on, this flame lights the gas flowing out of the burners. The advantage of the standing pilot system is that it is simple and completely independent of any outside power source. A minor drawback is that the flames continuously consume fuel even when the stove is not in use. Early gas ovens did not have a pilot. One had to light these manually with a match. If one accidentally left the gas on with the oven door closed, gas would fill the oven and eventually the room. A small spark, such as an arc from a light switch being turned on, could ignite the gas, triggering a violent explosion. To prevent these types of accidents, oven manufacturers developed and installed a safety valve in the oven. The safety valve uses a pilot flame to ignite the main burner when the oven is turned on. The pilot flame heats a thermocouple that sends a signal to the valve to stay open. If a draft blows out the pilot flame or it goes out due to loss of gas pressure, the thermocouple cools and signals the valve to close, shutting off the gas to the oven.
Electric ignition stoves use electric sparks to ignite the surface burners. This is the "clicking sound" you hear just before the burner actually lights. If the power fails, surface burners must be manually match-lit. Electric ignition for ovens uses a "hot surface" or "glow bar" ignitor. Basically it is a heating element that heats up to gas's ignition temperature. A sensor detects when the glow bar is hot enough and opens the gas valve.