Why is there lime scale?
The formation of hard lime scale at the container walls by the CaCO3 content of water is a consequence of the scarcity of nucleation centers in ordinary water. When the concentration of the CaCO3 exceeds the solubility, the solidification can begin only at appropriate starting points most of the time at foreign matter. If no foreign matter is present in the form of particles in the liquid, solidification can start only at the walls of the container. Ordinary water tends to surround any foreign particulate with complexes of 100 to 200 water molecules each. The water molecules agglomerate around every foreign particle in ordinary water. They form cages around them which makes them ineffective as nuclei. Then, the container walls are the only non-water substances available. The resulting crystals are of the dendritic mode. They are characterized by few starting points attached firmly to the wall and extended systems of crystals clinging to one another and to the wall around the starting p
