Observe carefully the process of heating, boiling and boiling water in the kettle. You will find that the kettle almost stops making noise before boiling.
Before boiling, the kettle almost stops making noise, because when the liquid heats up enough, the bubbles will stop collapsing, making a characteristic noise, will float to the surface, and the liquid will boil.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.