EXPERIMENTS:  Test Tube Flute

Blow across the top of a test tube until you hear a sound.  Now pour different amounts of water in and notice how the sound changes!  What’s happening:  the water changes the way the sound vibrates in the test tube, resulting in different pitches! 

Repeat this experiment by putting different amounts of water in glasses that are the same size.  Strike the side of each glass lightly with a metal utensil.  Notice the differences in pitch.

This is physics!