Question

1. When you boil water in an aluminum kettle, the kettle is safe and sound despite the

fire. But once the water in the kettle dries up, the kettle burns out quickly. Try to
analyze this phenomenon from the point of view of heat transfer.

Answer 1

When you boil water in an aluminum kettle, the heat transfer from the fire to the kettle is primarily through conduction. The heat flows from the flame, through the metal of the kettle, and into the water. As long as the water is present, it absorbs a significant amount of the heat, preventing the temperature of the kettle from rising too high.

However, once the water boils off and the kettle is empty, the heat transfer from the flame to the kettle becomes less efficient. The metal of the kettle begins to heat up rapidly, and the temperature of the kettle increases significantly. As the temperature of the metal increases, the metal becomes more prone to burning and can eventually become damaged or even catch fire.