The electrical motor and fan inside a hairdryer (also called blow dryer) are designed to generate a powerful flow of air to dry your hair. This air passes over a heating coil that warms the air, speeding up the evaporation of water on your hair’s surface. Hair dryers come with a variety of attachments including diffusers, airflow concentrators and comb nozzles that help to focus the flow of hot air onto particular sections of your hair to achieve specific styling effects.
The bare coiled nichrome wire that forms the heating element in most modern hair dryers is a poor conductor of electricity, and it doesn’t oxidize quickly at high temperatures. As the air passes through the long barrel of the dryer, it heats up and overheats, but the hot air is blown out by the fan and replaced with cooler air. In some models, the heating element is coated with fancier materials like crushed tourmaline to make it more efficient.
As the heat from the heating coil travels down the hair dryer, it evaporates any remaining water in your hair’s surface and makes them a little less wavy or frizzy. The hot air also raises the temperature of the surrounding air, which can cause more moisture to move out from your hair and into the air. To prevent overheating and fires, the circuit that supplies power to the heating element often includes a bimetallic strip made of two sheets of metal that expand at different rates. When one sheet of metal reaches a critical temperature, it trips a switch to cut off power to the hair dryer. hairdryer