Mind you, you can use edible dry ice, but it is also solid carbon dioxide, and its chemical composition is called "dry ice". "Dry ice" is a better refrigerant than ice. Its cooling temperature is much lower than that of ice, and the low temperature of -78℃ can be produced by using "dry ice". Moreover, after melting, "dry ice" will not become liquid like ice, but directly evaporate into dry carbon dioxide gas with extremely low temperature, so its refrigeration effect is particularly good.