We did an experiment to find out how water is heated as a result of sunlight. We had a bowl of water which we heated with a copper plate on the water surface, through which we sent a sinusoidal current. We didn't use a lamp, because water doesn't absorb visible light very well and since our bowl is not very deep, the effect wouldn't be as pronounced with a lamp. In the bowl we had a number of temperature sensors at varying depths. We found that, with increasing depth, the output of the sensors had decreasing amplitudes and increasing phase shifts: http://img15.imageshack.us/img15/1381/wstr3.png [Broken] We are now looking for a real world example where this effect occurs as well. Our teacher said the deeper layers of the ocean might be applicable, because convection won't be a factor there (we only want to see how the sunlight heats the water) and the water doesn't move much. If you put a number of temperature sensors in a deeper layer of the ocean, would you get a similar result as the one in the above graph?