a. Why soil is important
b. Clay, sand and silt
c. pH
d. Erosion (rill, sheet, wind)
e. How to operate a microscope
f. Micro-organisms (if creek water was observed)
g. Soil color
h. Soil texture
i. Soil grain size
j. Soil horizons
k. How to prepare a wet slide

Write the previous topics on the board and allow each group of four to pick one topic (or two if you feel that there is time). Give students time (based on your own judgment) to come up with a way to present their topic. This could be a good time for students to improve their skills in working together and in organization. Suggestions for improving their presentation may/could be:

1. Using chalk board to draw illustrations or diagrams Using old soil samples to demonstrate the different textures in front of the class

2. Explaining erosion by directly correlating it to rainfall, then correlate rainfall with altered
   pH ranges.