How a Curling Iron Works

The Electrical Power Source

Curling irons need electricity. The source of electricity can be a cord plugged in to the wall or a battery in the curling iron that is charged via a wall charger.

The Thermostat & Heating Element

When the curling iron is turned on, electricity passes through coils of metal in the heating element. The metal in this element is a very poor conductor of electricity, so instead of transferring the electricity efficiently, it creates heat. The curling iron's thermostat is used to set the iron's temperature by interrupting the flow of electricity once a specified temperature has been reached.

The Heat Resistant Handle

To keep the curling iron's user from being burned, a curling iron has a heat resistant handle. This handle is usually made of a heat resistant plastic with a buffer between the handle and the barrel to minimize heat transfer.

The Barrel

The barrel of the curling iron is the rounded area around which the hair is wound. It covers the heating elements. It is insulated from the heating element to prevent shocks. The barrel usually has a shiny, slick surface designed not to snag hair. The size of the curls created by the curling iron is defined by the diameter of the barrel. Some curling irons come with interchangeable barrels to allow for varying sizes of curls.

The Clip

Most curling irons have a spring loaded clip that runs the length of the barrel. This clip holds the hair in place as while the shape of the hair strands is changed by the heat of the iron.

How Hair is Curled

A strand of hair is essentially a long string of protein. When heated, its shape is easily changed. As the hair wrapped around the barrel of the curling iron warms up, its shape changes to that of the barrel. It retains the new shape of the barrel over a period of time, but eventually returns to its natural shape.