Understand the importance and value of fresh water and the need to protect and conserve this valuable resource.
There are enough materials for 15 groups. 
Realize that a variety of factors, including natural ones, contribute to the overall problem of water pollution. 
After completing this lab, students should understand the difference between point source and non-point source pollution and understand the role of nitrates and phosphates in the process of eutrophication. 
They will observe and examine the effects of nitrates, the effects of phosphates, and the effects of a combination of nitrates and phosphates in miniature 'ponds'. 
Teacher's manual and student copy masters are included.