|MadSci Network: Other|
When the rice crispies are made, superheated steam is used to expand them. When cooled to room temperature, the pressure inside the crispies is slightly higher than outside. The pressure is maintained by thin rigid walls of the pockets in the crispies. When the rice crispies come in contact with liquid such as milk, the cell walls rupture suddenly because the liquid soaks the walls and makes them weak. The popping sound is from the rupture of cell walls.
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