Hair Dryer

A hair dryer is a handy appliance using which, wet hair can be dried instantly. Any hair dryer has two switches and among them one is used for the purpose of switching on and switching off the device, whereas second switch is used for regulating the airflow rate. Some hair dryers have one more additional switch to regulate airflow temperature.

Function of Hair Dryer

A hair dryer blows hot air on to the surface of hair to evaporate water molecules from it. The heated air evolved from hair dryer changes the temperature of surrounding air. Since warm air has low moisture than room temperature’s air, water evaporates from warm place to room temperature air. In this way, a hair dryer works, and dries hair quickly.

To dry hair, mainly a hair dryer requires two parts to produce the blow of hot air. Those are

• a heating element and
• a simple motor-driven fan

Hair driers make use of the heating element and the motor-driven fan to convert electric energy to heat energy. The entire mechanism is quite simple.

• After plugging the hair dryer and switching it on, current conducts via the hair dryer.
• First the heating element gets power from circuit.
• Then the current forces the electric motor to spin in, which in turn causes spin to fan.
• The air current produced by fan is passed over the hair dryer barrel by the heating element.
• After the air flows via heating element, the produced heat humidifies the air by forced convection.
• Then the hot air comes from edge of the barrel.

Heating a Hair Dryer

In most of the hair dryer, a coiled nichrome wire is used as heating element, which is wrapped with mica boards.

This material is a combination of chromium and nickel. This alloy is used as heating element in almost all household appliances from hair dryers to toasters. This material has two important features.

• It is very poor conductor of electricity in comparison to copper wire. So, resistance of this wire is very high to become hot because complete current can’t flow from it.
• Even if it is heated, it doesn’t get oxidized easily. In case of other metals like iron, they get quickly oxidized if temperature is increased.

The air current developed from fan is forced via the heating element by the hair dryer‘s shape. Whenever the air enters the barrel, it is very cooler rather than the nichrome coil, so heat travels from wire to air. Similar to compressed air by convection and fan, it is substituted by a cooler and the rotation is repeated again.

How Air Blows by Hair Dryer Becomes Hot?

The origin of hot air in a hair drier is electricity and a heating element. Whenever a hair dryer is turned on, current passes from supply to hair dryer heating element and heats it up. The heating element heats up very quickly due to its material property. Then air blows from a fan designed inside the hair dryer, and air coming from hair dryer mixes with heat generated by heating element and comes out. In this way, due to the heat evolved in the hair dryer, it becomes hot.

Here’s a cool video that demonstrates how to make a hairdryer work