Jason Bradwell's 365/366 Photo a Day Blog

How does ironing work? The heat loosens the bonds between the long-chain polymer molecules in the fibers of the material. While the molecules are hot, the fibers are straightened by the weight of the iron, and they hold their new shape as they cool. Some fabrics, such as cotton, require the addition of water to loosen the intermolecular bonds.

Metal pans filled with charcoal were used for smoothing fabrics in China in the 1st century BC. In the late nineteenth and early twentieth centuries, irons were heated by fuels such as kerosene, alcohol, whale oil, natural gas, acetylene, or even gasoline.

The invention of the resistively heated electric iron is credited to Henry W. Seely in 1882. These had no easy way to control their temperature, and the first thermostatically controlled electric iron appeared in the 1920s. Later, steam was used to iron clothing, with credit for the invention going to Thomas Sears.