1. The problem statement, all variables and given/known data On his honeymoon, James Joule tested the conversion of mechanical energy into internal energy by measuring temperatures of falling water. If water at the top of a Swiss waterfall has a temperature of 10.0 degrees Celsius and then falls 50.0 m, what maximum temperature at the bottom could Joule expect? 2. Relevant equations change in internal energy = mgh 3. The attempt at a solution I'm sure this question is easy I must be missing something, the change in internal energy is mgh but we have no mass? The answer is (10.0 + 0.117) but I don't see how this was found.