Simpler alternative to resonant water columns. No need for water and its inevitable mess. A tuning fork is struck and held at the end of an open-ended hollow resonance tube. While listening to the tuning fork, students slide the expandable column until the tuning fork sound is at its loudest. At this point, the air column is in resonance with the tuning fork. The length of the tube during resonance has a relationship to the wave frequency of the tuning fork. Students then use their measurements to determine the wavelength, frequency, and velocity of the sound waves. Excellent hands-on wave measuring activities. Includes tuning fork, expandable resonance tube, end tube plug, complete background information and instructions.