Standard rice cookers have a heating element and a temperature sensor or thermostat positioned beneath the inner bowl, which is made of metal to conduct and distribute heat evenly. They feature one or more simple control switches to commence the cooking process. Once turned on, the bowl begins to heat up, which in turn begins to transfer the heat to the water in the bowl.
The heat brings the water to a boil and coverts it to steam, at which point the rice begins to absorb the moisture and cook. The machine will automatically set the cook time to the proper amount based upon the amount of rice and water used. Once the rice absorbs all of the water, the temperature will start to rise. Sensing this change, the rice cooker will either automatically shut off or switch to a warming cycle.