Soymilk is a kind of colloid, which has a characteristic that it is easy to sink when it meets electrolytes, just like river water is also a kind of colloid. When the river flows to the seaside, it meets the electrolyte of seawater, and the sediment in the river will sink, forming a delta for many years. When soymilk meets electrolytes such as gypsum, some tiny particles in it will sink and form tofu after pressure forming. Therefore, there is no chemistry in the process of ordering tofu with brine.

There are many similar examples in daily life. It seems that blood is also a colloid, and ferric chloride is an electrolyte in the hemostatic plaster. When the hemostatic plaster is contacted with the remarks on the wound, the blood will coagulate and block the wound, thus achieving the hemostatic effect.