3 ms·

Apologies for the ADHD induced tangent. Has anyone else noticed that regular little party balloons seem to have a passive noise cancelling effect? If you brin

by jcims 2y ago

Apologies for the ADHD induced tangent. Has anyone else noticed that regular little party balloons seem to have a passive noise cancelling effect? If you bring them close to your ear there's a zone of 'dead air' when they are maybe an inch away. My theory was that there's something in passing through the rubber envelope that creates a phase delay or inversion, but it could just all be in my head lol.

hinkley 2y ago
Balloon hats for autistic and sensitive people.
jareklupinski 2y ago
im curious about replicating this
elicash 2y ago
Do you see a difference regardless of helium or air? I assume from your description that it has to be inflated to work.
- bithive123 2y ago
  Helium is apparently great for soundproofing: https://www.youtube.com/watch?v=jxOzpPJbnTI https://www.youtube.com/watch?v=jxOzpPJbnTI (a great demonstration of sound suppressing properties of helium) I am a light sleeper and would love to use it somehow in my bedroom, but keeping it contained is tricky.
tasty_freeze 2y ago
It seems like the effect would be very frequency specific.
tastyfreeze 2y ago
Having filled a room with balloons, this is very noticeable. It also make heating the room difficult.
- roflmaostc 2y ago
  heating difficult? Why would that be?
  - tastyfreeze 2y ago
    Pretty much kills convection. Each balloon is like an insulation cell.
- tasty_freeze 2y ago
  Holy cow, I read your comment and thought, "Wait, I didn't write that!" Nice to meet you, doppleganger.
benplumley 2y ago
Could it be an interaction between static electricity from the balloon and tiny elements in the ear?
codazoda 2y ago
My wife makes balloon arches and I've never noticed but this sounds fascinating. Maybe I'll get her to work, for "science". :P Note: Her balloons are not typically helium filled, so the other users question about air/helium might make a difference.
Tade0 2y ago
The latex from which the balloon is made is a decent soundproofing material, so what you're hearing is likely just that.
LikelyClueless 2y ago
it maybe acting as an acoustic lens. https://www.youtube.com/watch?v=RLBmWF9Xo10 https://www.youtube.com/watch?v=RLBmWF9Xo10 edit: Steve Mould's video "I Made a Lens, But for Sound" demonstrates how balloons filled with gasses of different density than the surrounding air, act as a lens on sound waves. Helium filled balloons will scatter sound because the helium is less dense than air. He shows how a balloon filled with carbon dioxide can focus the sound.
- kurthr 2y ago
  At the old Exploratorium in the Palace of Fine Arts there was an exhibit that had a large 3-4m balloon filled with something heavy (Argon or maybe SF6?) and two points on the floor at the foci of the balloon. You could whisper at one focus and hear it easily at the other. I think it has been replaced with a more durable pair of concrete parabolic reflectors with similar effects.
- jcims 2y ago
  Oh dang! I bet that's it! Nice find, thank you!
- 0xbadcafebee 2y ago
  Somebody wrote a paper on it in 2008: https://physics.byu.edu/docs/publication/644 https://physics.byu.edu/docs/publication/644 A balloon filled with a gas that has a different sound speed than that of air has been used as an acoustic lens. One purpose of the lens is to show refraction of sound waves in an analogy to geometric optics. We discuss the physics of the balloon lens demonstration. To determine the validity of a gas-filled balloon as a classroom demonstration of an acoustic lens and to understand the corresponding phenomena, its physics is considered analytically, numerically, and experimentally. Our results show that although a geometric analogy is a good first-order approximation, scattering theory is required to fully understand the observed phenomena. Thus this demonstration can be adapted to a wide range of students, from those learning the basic principles of refraction to advanced students studying scattering Here's Harvard demonstrating it too: https://sciencedemonstrations.fas.harvard.edu/presentations/refraction-sound https://sciencedemonstrations.fas.harvard.edu/presentations/...
deleted 2y ago
[deleted]
Brian_K_White 2y ago
Do other smooth surface spherical objects have the same effect? Sound reflects off smooth surfaces. The ballon is probably just acting like any simple physical obstruction, because the surface does a lot all by itself even if theres almost no substance. The air inside the ballon is also at a different density than outside, without helium, because of the elastic tension in the rubber. The air inside is always slightly compressed vs outside. I have no idea how much the two densities must differ to make the accoustic lense effect. I din't think it's this, just everyone seemed to be overlooking that even plain air will also have a different density.
- chipsa 2y ago
  Density does not affect the speed of sound of a gas. Temperature and molar mass does. So increasing the pressure of a given composition of gas won’t change anything, assuming you can bring the temp back down. Helium is obviously a different molar mass. But also dry air vs moist air can have an effect.
deleted 2y ago
[deleted]
metalman 2y ago
just the humidity level in the gas used to fill a balloon is going to have a significant effect on its properties, human breath will have more c02 that air and s higher humidity. Any canned pressurised gas, will be pure with zero humidity. Heating exchange works through convection cells, the greater the number and the smaller they are, the lower covective heat transfer will happen, so filling a room with balloons, and you have made foam, and at that point the acoustical properties must be pronounced fun stuff The activity of silk working as a sound absorber is its property of bieng one of(the) best heat conductive substances, and as a basic fact, all sound is eventualy turned into heat The silk is presumably working to convert the mechanicsl motioninduced by sound into heat, quickly disapating it and releasing it to the air.
amarcheschi 2y ago
Definitely

by jcims 2y ago

hinkley 2y ago

Balloon hats for autistic and sensitive people.

jareklupinski 2y ago

im curious about replicating this

elicash 2y ago

Do you see a difference regardless of helium or air? I assume from your description that it has to be inflated to work.

bithive123 2y ago
Helium is apparently great for soundproofing: https://www.youtube.com/watch?v=jxOzpPJbnTI https://www.youtube.com/watch?v=jxOzpPJbnTI (a great demonstration of sound suppressing properties of helium) I am a light sleeper and would love to use it somehow in my bedroom, but keeping it contained is tricky.

tasty_freeze 2y ago

It seems like the effect would be very frequency specific.

tastyfreeze 2y ago

Having filled a room with balloons, this is very noticeable. It also make heating the room difficult.

roflmaostc 2y ago
heating difficult? Why would that be?
- tastyfreeze 2y ago
  Pretty much kills convection. Each balloon is like an insulation cell.
tasty_freeze 2y ago
Holy cow, I read your comment and thought, "Wait, I didn't write that!" Nice to meet you, doppleganger.

benplumley 2y ago

Could it be an interaction between static electricity from the balloon and tiny elements in the ear?

codazoda 2y ago

My wife makes balloon arches and I've never noticed but this sounds fascinating. Maybe I'll get her to work, for "science". :P Note: Her balloons are not typically helium filled, so the other users question about air/helium might make a difference.

Tade0 2y ago

The latex from which the balloon is made is a decent soundproofing material, so what you're hearing is likely just that.

LikelyClueless 2y ago

it maybe acting as an acoustic lens. https://www.youtube.com/watch?v=RLBmWF9Xo10 https://www.youtube.com/watch?v=RLBmWF9Xo10 edit: Steve Mould's video "I Made a Lens, But for Sound" demonstrates how balloons filled with gasses of different density than the surrounding air, act as a lens on sound waves. Helium filled balloons will scatter sound because the helium is less dense than air. He shows how a balloon filled with carbon dioxide can focus the sound.

kurthr 2y ago
At the old Exploratorium in the Palace of Fine Arts there was an exhibit that had a large 3-4m balloon filled with something heavy (Argon or maybe SF6?) and two points on the floor at the foci of the balloon. You could whisper at one focus and hear it easily at the other. I think it has been replaced with a more durable pair of concrete parabolic reflectors with similar effects.
jcims 2y ago
Oh dang! I bet that's it! Nice find, thank you!
0xbadcafebee 2y ago
Somebody wrote a paper on it in 2008: https://physics.byu.edu/docs/publication/644 https://physics.byu.edu/docs/publication/644 A balloon filled with a gas that has a different sound speed than that of air has been used as an acoustic lens. One purpose of the lens is to show refraction of sound waves in an analogy to geometric optics. We discuss the physics of the balloon lens demonstration. To determine the validity of a gas-filled balloon as a classroom demonstration of an acoustic lens and to understand the corresponding phenomena, its physics is considered analytically, numerically, and experimentally. Our results show that although a geometric analogy is a good first-order approximation, scattering theory is required to fully understand the observed phenomena. Thus this demonstration can be adapted to a wide range of students, from those learning the basic principles of refraction to advanced students studying scattering Here's Harvard demonstrating it too: https://sciencedemonstrations.fas.harvard.edu/presentations/refraction-sound https://sciencedemonstrations.fas.harvard.edu/presentations/...

deleted 2y ago

[deleted]

Brian_K_White 2y ago

Do other smooth surface spherical objects have the same effect? Sound reflects off smooth surfaces. The ballon is probably just acting like any simple physical obstruction, because the surface does a lot all by itself even if theres almost no substance. The air inside the ballon is also at a different density than outside, without helium, because of the elastic tension in the rubber. The air inside is always slightly compressed vs outside. I have no idea how much the two densities must differ to make the accoustic lense effect. I din't think it's this, just everyone seemed to be overlooking that even plain air will also have a different density.

chipsa 2y ago
Density does not affect the speed of sound of a gas. Temperature and molar mass does. So increasing the pressure of a given composition of gas won’t change anything, assuming you can bring the temp back down. Helium is obviously a different molar mass. But also dry air vs moist air can have an effect.

deleted 2y ago

[deleted]

metalman 2y ago

just the humidity level in the gas used to fill a balloon is going to have a significant effect on its properties, human breath will have more c02 that air and s higher humidity. Any canned pressurised gas, will be pure with zero humidity. Heating exchange works through convection cells, the greater the number and the smaller they are, the lower covective heat transfer will happen, so filling a room with balloons, and you have made foam, and at that point the acoustical properties must be pronounced fun stuff The activity of silk working as a sound absorber is its property of bieng one of(the) best heat conductive substances, and as a basic fact, all sound is eventualy turned into heat The silk is presumably working to convert the mechanicsl motioninduced by sound into heat, quickly disapating it and releasing it to the air.

amarcheschi 2y ago

Definitely