The Physics Behind Every Kernel Pop - Popcorn Cannon A popcorn cannon, also known as a Chinese popcorn machine, uses pressure and rapid depressurization to pop entire batches of kernels almost instantly. Inside the sealed chamber, corn kernels are heated while the internal pressure climbs far above normal atmospheric levels. This high pressure raises the boiling point of water, so even as the kernels reach temperatures well above 100 degrees Celsius, the water inside them cannot boil or form ste