Physics
posted by Alex .
James Joule once attempted to measure the increase in temperature of the water in a waterfall resulting from its decrease in gravitational potential energy. How high would the waterfall have to be for the temperature at the bottom to be 1°C higher than at the top?

Well hey there. Using the equation for potential energy: mass x gravity x height and the knowledge that it takes 1 calorie (4.186 Joules) to raise the temperature of one gram of water 1 degree Celsius we can solve for the height.
(0.001 kg) x (9.8 m/s^2) x (h) = 4.186 J