How is the chemical reaction between water and lye utilized in soap making?

The chemical reaction between water and lye in soap making is called saponification. Lye, also known as sodium hydroxide, reacts with fats or oils in the presence of water to create soap and glycerin. This process helps to break down the fats and oils into smaller molecules, which then combine to form soap. Glycerin is a byproduct of this reaction and helps to moisturize the skin.