0The melodica is a free-reed instrument similar to the pump organ and harmonica. It has a musical keyboard on top, and is played by blowing air through a mouthpiece that fits into a hole in the side of the instrument. Pressing a key opens a hole, allowing air to flow through a reed. The keyboard usually covers two or three octaves. Melodicas are small, light, and portable. They are popular in music education, especially in Asia.