The following image shows the information about the solar panel to heat water. According to the image, the steps include sun rays, cool water in, transparent top, water pipe, box, and warm water out. According to this graph, the first step is cold water coming in through the inlet as the blue arrow shows, following the second step, which is sun rays coming down on the transparent top of the square box. You can see from this graph that the third step is the heat energy of sun rays heating cool water in the water pipe. The final step is the warm water out from the box through the outlet, as the red arrow shows. In conclusion, this graph is very informative.