Forced Resonance of Sound
How many harmonics can be created in a straw?
Try this
Use the Tone Generator at around 800 Hz. Submerge one end of a large straw (such as a “Giant Pixie Stick” straw) into a cup of water so that you can easily modify the length of the closed-end tube. Place the smartphone speaker near the end of the open part of the tube. What length of tube is necessary to generate resonance? Why?
Challenge yourself
- How many harmonics can be created in a straw with only one tone?
- What happens to the necessary length of tube as the frequency of the Tone Generator is increased/decreased?