# Why are wide-mouth bottles hard to make sound from? **URL:** \ **Category:** Factual Questions\ **Created:** [September 19, 2024, 8:02pm UTC](https://boards.straightdope.com/t/why-are-wide-mouth-bottles-hard-to-make-sound-from/1007486 "2024-09-19T20:02:54Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [September 19, 2024, 8:02pm UTC](https://boards.straightdope.com/t/why-are-wide-mouth-bottles-hard-to-make-sound-from/1007486/1 "2024-09-19T20:02:54Z")
It’s fairly easy to blow over the top of an empty open pop bottle or similarly shaped container in order to produce a tone. Maybe that’s the bottle’s fundamental. But try to do it with a Gatorade bottle and it’s almost impossible. And by extension, it’s completely impossible to make a tone while blowing over the top of an open bowl. All I can surmise is that the relatively closed top of a pop bottle somehow makes the container resonate better or louder or somehow reinforces that tone. Any audiophile/acousticians out there able to enlighten me? Thanks. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [September 19, 2024, 8:28pm UTC](https://boards.straightdope.com/t/why-are-wide-mouth-bottles-hard-to-make-sound-from/1007486/2 "2024-09-19T20:28:38Z")
The sound is made by the resonant frequency of the opening coupled to pressure fluctuations within the container (i.e. a [Helmholtz resonator](https://en.wikipedia.org/wiki/Helmholtz_resonance)) which is partially dependent upon the area of the opening. > **[Sonorous Science: Making Music with Bottles](https://www.scientificamerican.com/article/sonorous-science-making-music-with-bottles/)** > > A musical physics project from Science Buddies Stranger ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 19, 2024, 8:33pm UTC](https://boards.straightdope.com/t/why-are-wide-mouth-bottles-hard-to-make-sound-from/1007486/3 "2024-09-19T20:33:48Z")
A voluminous bottle with a relatively modest opening is a Helmholtz resonator: > **[Helmholtz resonance](https://en.wikipedia.org/wiki/Helmholtz_resonance)** > > Helmholtz resonance, also known as wind throb, refers to the phenomenon of air resonance in a cavity, an effect named after the German physicist Hermann von Helmholtz. This type of resonance occurs when air is forced in and out of a cavity, causing the air inside to vibrate at a specific natural frequency. The principle is widely observable in everyday life, notably when blowing across the top of a bottle, resulting in a resonant tone. > The concept of Helmholtz resonance is fundamental in various... The bit of air in the area of the opening serves as a mass that vibrates back and forth, and the air in the container is a spring; the two together create a spring/mass system that wants to vibrate at a particular resonant frequency. As the opening gets larger and larger, the situation becomes more like **[a cylinder that’s closed at one end](https://en.wikipedia.org/wiki/Acoustic_resonance#Closed_at_one_end)**. These also have a resonant frequency, but the mechanism is different in that it relies on waves within the cylinder, i.e. the mass and the spring in this mass/spring system are one and the same. The problem comes when the width of such a cylinder is large relative to its length - and I’m afraid I don’t know why that is. You can definitely see it in pipe organ pipes - the ratio of diameter to length is fairly consistent across the entire range of pipe sizes. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [September 19, 2024, 10:10pm UTC](https://boards.straightdope.com/t/why-are-wide-mouth-bottles-hard-to-make-sound-from/1007486/4 "2024-09-19T22:10:10Z")
You can get a similar effect sometimes driving a car on the highway with an open window, but the vibration - driven by the car’s volume, is a very low hertz, more like a throbbing. I would say the OP’s answer is that it’s hard to blow a cosistent stream across a wider opening. Plus with larger containers, the frequency is often subsonic. > [@Machine\_Elf](#): > > A voluminous bottle with a relatively modest opening is a Helmholtz resonator I once demonstrated this to a friend’s child, and interestingly demonstrated it was more dependent on volume. Blow on an empty tall thin small bottle. Note the frequency. Take a full 2L bottle, pour out into the small bottle so it’s full. You now have a squat cavity in the 2L same volume. Blow on the 2L and the frequency sounds the same (to our ears).