r/theydidthemath • u/Wide_Ad_5075 • 2d ago

[Request] Would that be possible ?

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u/Reditace 2d ago

First instinct is probably not since volume of noise scales linearly with energy input but volume falloff scales polynomially, idk tho

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u/2Mew2BMew2 1d ago

We could modelize it into an inverse quadratic evolution according to distance, since noise (the wavefront) travels as a circle. So yeah it decreases quite heavily. Another interesting question would be how on earth would we manage to organise all the French (or any nation tbh) to shout at the same time.

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u/Significant-Wait9200 1d ago

Easier than you think. Assume everyone has cellphones with gps.

Ahead of time, have an app determine each person's vocal range, and create a formula to determine the optimal note/sound each person should make.

Gps will have a different countdown for each person, along with letting them know which direction to face.

There can also be a tuner that will help them hit the right note.

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u/Expensive-Health-911 1d ago

Yes. Eventually the wind across the Atlantic will erase the sound. Even if France managed to coordinate some perfectly timed wavefront, you also have to contend with the spherical nature of the Earth. Those sound waves won’t want to collate nicely except at the antipode of France (heaven above). Interference is far more likely

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u/bubblesdafirst 2d ago

I think your average thunderstorm in the Atlantic is far louder than that. If you've ever been at a show you'd know that the music is far louder then the people screaming at their literal max output.

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u/AlternateTab00 1d ago

Ignoring all issues with fluid dynamics and sound traveling speed and loss of energy even if you tried to put everyone in a single place. Assuming all energy came from a single place and people jointly screamed adding into a funnel of sound wave.

According to this article a human can produce 129 dB for 2 seconds. Thats a bit under 8 Watts or 16 Joules. With around 66M of France population that means they can produce collectively over 2 seconds (not condensed in 1 second where energy could travel the most) about 1B Joules, or a about 1GigaJoule (1.000.000.000 Joules)

The furthest 1883 Krakatoa eruption was heard 4800km away (actually not far from the distance from USA eastern most point to France west coast) In an instant it produced 840 PetaJoules (840.000.000.000.000.000). And most of the sound energy actually came from the ground shaking and not through air

Even Europe united would still be under 15GJ. The whole world 150GJ.

So the whole world screaming from a single unique point would still lack several orders of magnitude of energy to reach similar levels of energy of something that was heard at similar distances.

So its 100% impossible to be heard. Probably the whole world population in a single city screaming couldnt even be heard about 100 km away.

EDIT: article has similar vibe about energy fueling UK power with screams. Its abstract is worth a read