An electric fan is one of the simplest circuits that you can make. All it requires is a motor, a power supply and a fan blade.As long as you get the voltage and amperage right and there is nothing wrong with your motor, your electric fan should work for years without any trouble. Use a battery pack if you want to make a quick science project. Use a plug-in power supply for a more permanent fan.
Buy fan blades and a motor. Make sure that the fan blades have a hole in them which is the same size as the electric motor. Alternately, you can buy a kit including a fan, electric motor, power supply and housing such as the one linked to below.
Get a power supply with the right voltage and amperage for the motor. For a small electric hand fan, a battery holder such as the one linked to below should do the job. Alternately, you can buy an electric adapter that plugs into the wall.
Test the motor. Touch the positive lead to the positive lead of the motor, and the negative to the negative. Switch on the power supply.
Put the electric fan blade on the motor. Simply push the shaft through the hole in the blade. Use a drop of super glue to secure it.
Hook the power supply to the motor. Solder the positive lead to the positive terminal and the negative lead to the negative terminal.
Switch the circuit on. Plug it in or put in the batteries, and turn the switch to "On" if your power supply has a switch. The fan should start turning immediately.