The Guardian: Researchers led by Emmanuel Virot of CNRS in Paris believe that they have an explanation for the popping sounds of popcorn. They combined high-speed cameras and audio recordings of popping kernels to show that the pop is not from the cracking of the kernel shells. Instead, the shape of the kernel serves as an acoustic resonator and causes the release of pressurized vapors to create the audible pop. A similar effect causes the pop of champagne corks. The team also found that the kernels pop when the vapor reaches 180 °C and that the "jump" of the pop occurs when starch in the kernel expands into the fluffy leaves that give popped corn its appearance.
