The musical instrument I made is called a "Drumapluck". It is a combination of a percussion and a string instrument. When you hit the bottom of the can sound waves bounce off the sides and make the sound louder. The rubber bands are the strings. The tone of each rubber band can be changed by loosening or tightening the rubber band. Tightening the rubber band mades it vibrate faster and makes the pitch higher. The sound waves again bounce off the can and resonate and make the sound louder.