The principle of electric blowing is the thermal effect of current. An electric current generates heat through a heating element having a relatively high resistance. Then the fan blows the wind out. Therefore, it is normal for the hair dryer to get hot.
The hair dryer was invented at the end of 19. Modern hair dryer is a mechanical device, which speeds up the airflow by electric means, thus generating wind power and raising the air temperature. Hair dryers are mainly used for hair drying and styling, but they can also be used for local drying, heating and physical therapy in laboratories, physical therapy rooms, industrial production and artistic design.