Range is an appliance that provides heat for cooking. A range has a cooktop with several heating areas, and one or two ovens. Ranges are sometimes referred to as cookers or stoves, though the word stove properly means an apparatus used for heating. In the United Kingdom and some other countries, the cooktop is called the hob. There are two chief kinds of ranges: (1) electric ranges and (2) gas ranges. For information about microwave ovens, see the article on Microwave oven.
Electric ranges
have heating units, in which an electric current generates heat. Most electric ranges have four circular heating units on the cooktop and one or more units in each oven. In some ranges, a smooth ceramic surface covers the cooktop units.
Most heating units have an outer surface that consists of a metal tube in two parts. Each part has a spiral shape and encloses a coil of wire. Electric current passes through the coil and heats the coil and the metal tube. An insulating material prevents electric current in the coil from reaching the surface of the tube.
A magnetic induction cooktop works only with pans made of magnetic materials, such as iron and steel. The cooktop passes alternating current through metal coils to create an area of magnetic force called a magnetic field. The magnetic field creates a current in the pan, heating the pan—and so the food—but not the cooktop.
The amount of heat produced by a heating unit can be regulated easily. Some cooktop units have controls that regulate which one of two possible voltages of electric current is supplied to the coil. The coil becomes hotter at the higher voltage. Controls may also regulate whether both of the coils heat up or whether only one heats up. Another kind of cooktop unit control turns the current on and off at intervals that vary with the heat desired. The longer the current flows through the unit, the higher the heat. Some cooktop units and most oven units are regulated by thermostats (see Thermostat ).
Some modern ovens are convection, or hot-air, ovens. In such ovens, blowers circulate hot air around the food. Convection ovens cook faster, more evenly, and at a lower temperature than regular ovens.
Other modern ovens called halogen ovens heat food with halogen lamps, a type of light bulb that produces great light and heat. Still others use a combination of halogen heat and short radio waves called microwaves.
Gas ranges
have burners on the cooktop and in each oven. A burner mixes air with natural gas, synthetic natural gas, or LP-gas (liquefied petroleum gas). The resulting mixture flows through small holes in the burner. The mixture is ignited by a spark produced by a built-in electric device or a pilot light near the burner. A pilot light is a small flame that burns continuously.
The heat that is produced by a burner depends mainly on the amount of gas flowing to it. A valve regulates the gas flow to each burner. Hand-operated valves control most cooktop burners. Thermostats operate the valves of most oven burners and some cooktop burners.
History.
The first practical cooking stove was designed in the 1790’s by Benjamin Thompson, Count Rumford, a British statesman and inventor. This stove, a boxlike brick structure, had holes in the top to hold pots. Before that time, many people used fireplaces for cooking as well as for heating.
During the 1830’s, advances in ironmaking and transportation made cast iron widely available. As a result, iron cookstoves became popular. Most of these early stoves burned wood. In 1855, Robert W. Bunsen, a German chemist, invented the first practical gas burner. In the 1860’s, ranges based on Bunsen’s burner became popular in cities that had gas piped into homes for use in gaslights. People who lived in rural areas began to use gas ranges after 1910, when gas became available in pressurized containers.
Electric ranges were first sold in 1909. The early electric ranges cooked slowly, and few people bought them. After the modern cooking unit was developed in 1930, electric ranges became popular. Microwave ovens appeared in the mid-1950’s. In the early 1980’s, convection ovens began to gain popularity.
