February 1, 2012
A quiet whisper contains less than a nanowatt of power. A human shout is a little more than a microwatt, and when you get 68,000 screaming fans inside Indianapolis’ Lucas Oil Stadium—one of the NFL’s louder indoor stadiums—the Super Bowl represents a big game and an incredible source of sound. And all those shouts add up to real power.
In Sound and Sources of Sound, Anne P. Dowling writes: “The total energy radiated by the combined shouts of the Wembley cup final crowd during an exciting game being about that required to fry one egg!” Really? Well, American football fans probably outdo British soccer fans; anecdotal reports suggest that indoor stadiums can reach up to 117 decibels. Still, the question remains: Does the Super Bowl create enough power to fry up a dozen eggs?
I called Mark Sheplak at the University of Florida. He’s a mechanical engineer who has modeled how much power could be harvested from the acoustic liner of an airplane engine. (He’s found that the take-off of many commercial flights can generate the same amount of noise as roughly equal all the human shouts in the world, and this intense concentration of waste noise can be enough to power on-board acoustic monitoring systems.) “I don’t know if there would be enough sound in a stadium to get anything,” he says. “It would have to be really, really loud.”
Before we go much further, it’s also worth pointing out that an egg is a heterogeneous substance. “The various kinds of proteins do not all coagulate at the same temperature,” Herve This writes in Kitchen Mysteries. “One forms at 61°C another at 70°C, and so on….” The combination of cook time and temperature ultimately yields different textures and viscosities (which César Vega writes about extensively in the new book The Kitchen as Laboratory). For the sake of simplicity, let’s forget about any energy lost in cooking—heating a pan or allowing flames to escape around a pan—and take a wild guess at the power required to heat the yolk of a chicken egg to 85°C at sea level. (Engineers and food scientists, please feel free to weigh in). Let’s call it 30 watts to fry an egg: Five minutes of intense screaming.
The bigger problem here is that all these screaming fans are spread out over 1.8 million square feet and, to cook an egg, you would need to concentrate and harvest those sounds and convert them to heat. “You’re usually not terribly efficient,” Sheplak told me, “usually less than one percent efficiency of harvesting that energy. You need to be in a situation where it’s really loud. You can’t have a perpetual motion machine.”
So what might sound like a deafening cacophony during Sunday’s game might actually amount to only a single fried egg, if that. Perhaps thinking about how sports fans might actually cook an egg with their vocal cords demonstrates something else entirely: the pervasive use of the “fried egg” as a scientific analogy.
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