Bob2 began the afternoon session by introducing Chris (a.k.a. Godzilla or Dr. No). Chris started out by giving us some information on his background in biomedical engineering. He then went on by discussing the water cycle, with the students suggesting all the different places in Nature that water is found. He backtracked from oceans to rivers to tributaries to rain. This lead to the question "Does all the rain run into the river?". No, it doesn't. Some soaks into the ground, and some evaporates. Then it was time for an experiment. Chris lead the students outside. There they poured water on the grass and on the sidewalk. They found that the water on the grass soaked in faster than it did on the sidewalk. In fact, the water on the sidewalk ran off.

The students were then given a worksheet on the different types of surfaces on which the rain could land and asked which of the surfaces would absorb the rain the quickest. Chris then prompted them to run a rainfall model on the web (written, of course, by him). The model determines how much rain soaks in based on cover type, intensity of the storm, hydrologic condition, soil condition, and on the duration of the storm. His next example was of Kool-Aid dissolving in water. He used this to demonstrate that things that get in the water runoff can stay there if they're water-soluble. Bob2 collected the data from the students' results from the board.

The primary example was phosphorus. The phosphorus reappeared in a STELLA model of a lake. This charted the movement of phosphorus through an ecosystem, even including its plankton types and fish. The amount of phosphorus was the limiting factor for the growth of the plankton, and so when there are overwhelming amounts of phosphorus, the plankton population size balloons. When they die, their decay depletes the oxygen supplies of the water, and thus the fish die (a fishkill). The last model was of the water cycle. It showed how the water travelled through the different areas.