system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5, how do rice cookers know when the rice is done?
gpt
As the water/rice mixture is heated, that heat energy increases the temperature of the mixture until it reaches 100 C. At that point, the additional energy will convert the water to steam and the temperature will remain at 100 C. Once all the water boils away (which is when the rice is done), the energy will then start to raise the temperature of the cooked rice above 100 C. So the rice cooker just needs to sense when the temperature goes above 100 C and shut off. This is usually done with a metal strip that expands/bends as it heats, and when it reaches a temperature a little over 100 C, the metal strip bends enough to close a circuit and shut off the heat.