Hard... or soft? That's the watery wrangle on which listener Jo asked us to weigh in. She said: "my question is about drinking water. We drink gallons of the stuff in a lifetime, but which is better for us, hard or soft? My skin and hair prefer it soft, but what about teeth and bones? And which do our kidneys prefer?" Adam Murphy got the answer with the help of University of Cambridge chemist Ljiljana Fruk... Like this podcast? Please help us by supporting the Naked Scientists