This unit has five components linked sequentially: 1. Students should research the human generated sources that have contributed to the increase in the acidity of rain. At the conclusion of their research, students should understand the scope of the problem and be able to list and explain at least three areas where rain with low pH impacts humans and the natural world. In classroom discussion, students should be able to articulate their findings and discuss the validity of sources located as well as future implications if the problem remains unresolved. 2. In the second lesson, students should be able to work in a group to determine the portion of the phenomena (effects on aquatic systems, manmade structures, plants, etc.…) they would like to study and develop a plan to test their hypothesis with the appropriate controls. The plan should be presented to the class for critique prior to implementation. If the class is unable to locate areas of weakness, the instructor should ask questions intended to guide the class in the correct direction to produce relatively valid results. However, the students are responsible for their experimental design so they should be allowed to implement the experiment even if they are unable to correct problems perceived by the instructor - the students, as a group, should take ownership. During the course of study, students may be able to correct problems as they begin to run their experiment. If the problem cannot be corrected, the students should repeat the experiment or report the problem and how a researcher in the future might correct the problem to obtain more accurate results. 3. Lesson 3 requires that students implement their plan using available materials and following all laboratory safety procedures. 4. At the conclusion of their experiment, students will produce a formal lab write up using the word processing program of their choice. Student groups should divide the workload (the sections of the report) so that everyone contributes. One chart and one graph is required and must be produced on the computer as well. The instructor may want to require a rough draft to check student understanding of the process depending on the experience level of the class in producing the formal report. 5. After rough drafts are complete, students should share their results with the class. A discussion of results should be facilitated by the instructor. Students should help each other determine areas for further research.

Results of scientific inquiry--new knowledge and methods--emerge from different types of investigations and public communication among scientists. In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge. In addition, the methods and procedures that scientists used to obtain evidence must be clearly reported to enhance opportunities for further investigation.

Students should know how to participate effectively in discussion.

With their experiment in front of them, each group should share both their experimental design and their results with the class. The teacher will only facilitate the discussion and students should be encouraged to comment. Students should suggest other ways to test their phenomena and provide recommendations for further study.

The assessment for this day is informal. After students suggest further study, the instructor can assess understanding. The instructor may also choose to pose new problems to determine if students could suggest an experiment for a different, but related, situation. For example, many individuals talk to their plants believing that the human voice increases growth. How could that be tested? Some people believe that plants contain chemicals that tell them which way is up while others believe that environmental cues - such as the sun - determine in which direction the sprout will grow. How could that be tested?

Students will share their experiment with the class and participate in discussion while other students share. Students should be able to suggest further study and identify methods to test related phenomena.