Background
The sole purpose of the tea kettle is to boil water. Water for coffee and for many cooking uses does not have to be boiled, but fresh, cool water that is brought fully to a boil is essential for tasty tea. Although it is associated with making tea, the kettle's contents make excellent instant drinks or soups that are also best with boiling water or to produce steam for remedying colds.

History
Tea itself has been processed into three different forms in its history, making specific utensils essential. In its beginnings in China, tea was processed in blocks or cakes that had to be boiled after roasting and shredding; this required a tea kettle. The Japanese method was more refined; powdered tea was whipped in porcelain bowls with bamboo whisks. Leaf-tea (the most common form in the Western World for about 200 years) consists of different methods of picking and processing tea leaves. This tea requires steeping in boiling water, so leaves are put in pots filled with boiling water from the tea kettle. Block, powdered, and leaf tea must all be steeped in boiling water.

The tea kettle evolved from the cooking kettle that was hung on a hook on an iron post in the cooking fire. The hook was turned to move the kettle over the fire, and a "tilter" helped to pour water from the kettle. Kettles were made of iron, one of the first metals to be mined and processed.

In Japan, the iron cooking tea kettle became a small, rounded bowl with two short arms or loops (one on either side of the bowl) for pulling it off the hearth and a lid. A classic example of a bowl-type iron kettle dates from 1517. As methods of casting iron became more sophisticated, the outsides of these kettles were decorated, and the two arms became a spout and better handle. Iron casters who made tea kettles were highly respected.

Beautifully decorated examples of Japanese iron tea kettles with the spouted tea kettle shape known today date from the late nineteenth century. Iron kettles could withstand cooking fires, but serving ware emerged from the porcelain industry. Kettles obviously existed before tea pots because pots copied the shape, spout, and handle.

In Russia, water is heated in a samovar (literally, self-boiler), which is not a tea pot but an elaborate tea kettle made of metal with a central chimney for containing fire and boiling water in the surrounding vessel. Russians learned about the samovar from Persians during border disputes and trade efforts. A strong concentrate of tea is kept in a tea pot and warmed constantly on top of the samovar. Concentrate is poured into tea cups, and boiling water from a spigot on the samovar fills the cups and dilutes the concentrate.

The English began making tea pots of unglazed earthenware in the mid-seventeenth century, but silver became a popular material in the early 1700s. The first known silver tea pot is dated 1670, but, by the turn of the century, all tea servingware was made of silver including kettles. Silver kettles are still made today, but they have been surpassed in importance by aluminum and stainless steel for both stove-top and electric types.

In both England and the United States, the tea kettle's development was closely linked to the evolution of the stove. When stoves replaced cooking fires, the kettle was pulled from the fire and given a place on the stove. Most kettles are shaped like modified globes with flat bottoms to sit on stove plates. Kettles became ornaments for kitchens when they were manufactured with different metals like copper and decorated with interesting handles and enamel.

Electrifying the kettle followed in the early twentieth century. Although the first kettles were seated on individual electric coils, heating elements were soon built in and more refined models appeared.
Source: Gillian Holmes "Electric Tea Kettle". How Products are Made. Volume 7 (1999). FindArticles.com. 03 Jun. 2008. http://findarticles.com/p/articles/mi_gx5205/is_1999/ai_n19125052