Tightening the strings on a guitar increases the tensile force on the string. This force limits the amount of movement the string can make when you pluck it, and as such, the distance it vibrates decreases (which translates into a higher frequency of vibration).

How does tightening a string change its frequency?

Tightening the string gives it a higher frequency while loosening it lowers the frequency. ... The density of a string will also affect its frequency. Remember that dense molecules vibrate at slower speeds. The more dense the string is, the slower it will vibrate, and the lower its frequency will be.

How does the tightness of a string affect pitch?

Applying too much tension to a string tightly can raise it to the pitch of the next note, while loosening it can easily lower it the same amount. Increasing the tension raises the pitch. The length of a string is also important. When a string is supported at two points and plucked, it vibrates and produces sound.