How Does a Kettle Work?

Written by sylvia cini | 13/05/2017
How Does a Kettle Work?
James Watt, inventor of the modern steam engine, was inspired by the tea kettle. (Thomas Northcut/Photodisc/Getty Images)

Understanding how your kitchen tools and appliances function makes it easier to take care of minor repairs and problems on your own -- without paying a repairman or suffering the embarrassment of asking for help. The tea kettle, also called a whistling kettle or whistling pot, is a kitchen staple that is simple but misunderstood.


Tea kettles are tightly sealed containers that hold water while it heats. Although they might seem equivalent to pots and saucepans, the shape of kettles sets them apart. These cooking vessels are designed with broad bases and narrow openings at the top; this maximises the size of the surface in contact with the stove and prevents hot air from escaping during the cooking process. Kettles designed for use with loose tea leaves may have a removable mesh basket for steeping.


Most tea pots are designed for conductive heating, the direct transfer of heat from an area of high temperature to low, namely the hob to the tea kettle. Any material that is capable of withstanding heat without losing shape or transferring foreign particles into boiling water can be used to make a tea kettle. Most kettles are made from a lightweight metal such as aluminium. Some speciality kettles are made of stone or cast iron. Flat-top stoves, which heat through induction, are generally compatible with the same cookware as a coil hob. However, specialised flat-top cookware offers superior performance.


Kettles whistle when the gas inside tries to escape. When you heat the water in the pot, some of the liquid is converted from a liquid into a gas. These gas particles, charged with energy, move around the kettle quickly and take up more space than the water particles. As more water is converted into a gas, the particles are forced up the spout through a series of disks, causing a whistle. The tone of this whistle is determined by the length of the spout and the size of the holes in the disks -- larger holes result in a lower tone.


To repair a loose handle on a hob kettle, use a compatible screwdriver and tighten the screw located at the top of the handle. Hold the handle in place as you rotate the screwdriver clockwise. Fix dents in a metal kettle by gently tapping them out. Fill the pot with rolled kitchen towels to stabilise the interior wall. Then turn the pot so that the bump is facing upward, cover your hammer with a towel and strike the side. If the dent is on the inside of the kettle, reverse the operation, inserting the hammer into the pot and tapping outwards. Remove the kettle handle to make it easier to manoeuvre.

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