How does a toaster work?
Inside a toaster are thick wires arranged in panels that heat up and toast your food. When you push down the lever that lowers your bread, it catches on a hook inside, turning on the heater. While your bread turns brown and crispy, a special metal switch inside the toaster gets hot, too, and bends. After a certain amount of time it bends so much that it pushes on a bar that releases the lever from the hook, and the toasting stops. This action also releases a spring, which pushes the lever up again—and your toast pops up.