MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY
Water hardness test. Temporary hard water becomes cloudy when boiled, which is what has happened to the water here. Temporarily hard water is caused by dissolved calcium carbonate that precipitates out of solution when the water is boiled. This is in contrast to the calcium and magnesium sulphates or chlorides found in permanently hard water, that are unaffected by boiling.
Model release not required. Property release not required.