Soymilk is a kind of colloid, and it is easy to sink when it meets electrolyte, just like river water is also a kind of colloid. When the river flows to the seaside and meets the electrolyte of seawater, the sediment in the river will sink and form a delta for many years. When soybean milk meets electrolytes such as gypsum, some fine particles will gather and sink, and after pressure molding, tofu will be formed. Therefore, there is no chemical change in the process of ordering tofu with brine.

There are many similar examples in daily life. It seems that blood is also colloid, and ferric chloride is used as electrolyte in the hemostatic patch. When the hemostatic patch comes into contact with the notes on the wound, the blood will coagulate and block the wound, thus achieving the effect of hemostasis.