experiment consists of a clear plexiglass tube of water with a speaker
mounted over the tube. The level of the water can be adjusted by moving
the reservoir on the right. As the water level changes the size of the
air column that vibrates with the sound of the speaker changes. The quarter
and three quarter wavelength resonance points for a pipe closed at one
end can be clearly heard and the speed of sound calculated based on knowing
the input frequency and the length of the tube at resonace.