| − | [[Water]] that has certain dissolved [[ion|ions]] in it, predominately [[calcium]] ions.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> | + | '''Hard water''' is [[water]] which has certain dissolved [[ion|ions]] in it, predominately [[calcium]] ions.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> |