Pendulum----Principle of isochronism
Fuse----Excessive current will cause heat to increase and burn the wire
Air valve of the pressure cooker --- - Avoid excessive pressure in the pot, open the lid
Steam the steamed buns and add alkali - sodium carbonate, Na2CO3, heat to generate CO2, making steamed buns "greasy"
Lightning rod-- --Spike discharge, which guides electricity from clouds downward to prevent it from hitting buildings