Draw an indicator line around the top of the bowl (you will fill the bowl with water to this line). If you plan to leave the experiment set up for several days, the indicator line will help you see the amount of evaporation.
Spread out the absorbent paper over an area just larger than the size of the aquarium.
Fill the bowl with water to the indicator line, and add a drop of food coloring to the water so that it is easier to see the water as it moves through the aquarium. Put the bowl at one end of the paper.
Place three thermometers on the paper, one near each end and one in the center. Turn the empty aquarium upside down over the paper. Make sure the aquarium covers the bowl and three thermometers.
Shine a bright light down through the glass directly over the bowl of water. Brighter bulbs lead to better results. The light bulb end represents the equator end and the opposite end represents Earth's pole.
Leave the light shining over the water bowl overnight.