Closed-Closed tube: A closed-closed tube is a musical instrument or resonator that has both ends closed, causing sound waves to reflect off the closed ends.
Open-Open tube:An open-open tube is a musical instrument or resonator that has both ends open, allowing sound waves to travel through it.
Harmonics: Harmonics are multiples of the fundamental frequency produced by vibrating objects. In tubes, harmonics determine different pitches created by altering length or shape.