A guitar is six strings wired across a long-neck wooden box with a hole in its body. Strings are stretched straight along the neck, with each end reeled onto a peg and space in between every adjacent pair which decide the tone of the string. The diameters of every string is different. It is more and more long for the diameters from the first string to the sixth. The string which is thick control the low pitch and the slender one control the high pitch. When you stir the string. There will be some standing waves in the strings. The waves go through the string to the body of the guitar. The wooden part vibrate and then we will hear the sounds. The changement of the place you place your hands on and the technique of your another hand produce many difference of the sounds.

The guitar has a fretted neck - across the width of the neck. There are small ridges spaced out from the top of the neck down to the bridge. Frets are used to position your fingers to find the desired note.

As the technology progress, many people use electric guitars. This kind of guitars is based on the the vibration of the strings changing to electroacoustic and then adding many different effects.