Cut the wooden tube to a length of 12 to 18 inches. If you are comparing the different sounds from different length clarinets for your project, cut several tubes of different lengths.
Mark on the tube with a pencil where you want the finger holes to be. Finger holes should be at least 1 inch apart. Draw six holes per tube.
Cut out the circles you drew for the holes by moving the blade on the utility knife up and down and at an angle around the hole until you can pop out the hole or shake it out with the tube turned upside down. Sand the hole smooth with a small piece of sandpaper.
Make a slit in the top of the clarinet for the mouthpiece. Cut the slit from the top down into the tube about 2 inches deep. This will serve as your reed.
Sand the slit smooth with some sandpaper by inserting the sandpaper in the slit and pulling it back and forth.
Place the clarinet into your mouth and blow on the mouthpiece end. The air passing over the slit you cut will cause the tube to vibrate and produce sound.
Cut different length slits in each clarinet you make and compare the sounds for both differences in the length of the clarinet and difference in the length of the slit. Make notes in a science journal on how the different sizes of clarinets, slits and number of finger holes affect the sound produced.