[ELI5] How does a rice cooker “know” the timing to switch from cook to warm when there’s no more water in it?

Question

[ELI5] How does a rice cooker “know” the timing to switch from cook to warm when there’s no more water in it?

In: 825

Answer 1

There is an alloy that has the property of losing its magnetism when heated to a certain temperature. There is a magnetic latch that holds the spring loaded contactor closed, (if you look under the pot part of a rice cooker there is a springy plunger which works with the lever/button you use to start the cooker to bring the magnet in contact with the latch.) When all of the water is boiled away/absorbed by the rice the temperature of the cooker climbs above the temperature where magnetism is lost and catch is released breaking the circuit. When it cools down it regains its magnetism. It is really an amazing, simple, lucky gadget.