A bain marie also known as a water bath. 3-6 divisions are available. Typically the inner container is immersed about halfway into the working-liquid. The smaller container, filled with the substance to be heated, fits inside the outer container, filled with the working-liquid (usually water), and the whole is heated at, or below, the base, causing the temperature of the materials in both containers to rise as needed. The insulating action of the water helps to keep contents of the inner pot from boiling or scorching.