valves
valves
valves
valves
valves
valves
Lower. By increasing the length of the air column in the instrument, the wavelength of the sound produced is longer, resulting in a lower pitch.
The pitch is changed on a Trombone by moving the slide or changing your ombisture.
The flute can produce multiple octaves by changing the way air is blown into the instrument and by using different fingerings to change the length of the vibrating air column. This allows the player to produce higher or lower pitches across different octaves.
valves
valves
ruler and tape measure
Length over which the column has no support is taken as unsupported length of the column