SLC #17B - Water Pollution 5th Grade Mary Gilstrap, Mrs. Smith & Ms. Brown References: • www.iit.edu/~smile/bi8701.html - This was the source for the lesson plan, which was modified from the outline presented in this website. • The attached worksheet was modified from one created by Meghan Knapp. Benchmarks: SLC 17: Analyze the impact of human activity on the ecosystems of the earth CPS Benchmark: SLC 17B: Students will identify the impact of human activities on the earth’s ecosystem (pollution, conservation of natural resources, erosion, and soil fertility). Objectives: To give the students an idea of the impact of the various pollutants with which humans contaminate our water, as well as some techniques used to filter water. Materials: • Large “filtering tube” (or glass funnel) • Large glass tank or jar • Bag of charcoal pebbles, sand, and gravel - from a fish store • Micropore filter paper (coffee filters work) • Petri dishes • Chlorine (Either liquid or powder, from a pool supply store) • A strainer (like from your kitchen), or screening • Household product pollutants - These can be any number of things… some good examples are: motor oil, food dyes, scraps of paper, soil, leaves, clay balls, coffee grounds. • Tablespoon measure • Large Bucket (~5 gallons) Initial Demonstration: Show students the large bucket filled with water. Than demonstrate the tablespoon with water in it. The bucket represents most of the water on earth- salt water that we cannot drink. The tablespoon represents the small amount of fresh water on Earth that we can use. Target Observations: • Students should realize that fresh, drinkable water is a small percentage of the water on earth. Target Model: • Although there is a lot of water on earth, much of it is not usable, and fresh water is really a delicate resource. Procedure: What is pollution? What pollutes our water? Pollutants are represented by household products and added to the large glass tank filled with water. (Examples of pollutants can be found in the materials section.) Ask, “This water started out as clean fresh water… would you drink it now?” Students should immediately see the impact of the pollutants on the water. The water will be dirty. They should realize this water is not usable anymore (at least not for drinking) Target Revised Model: • Fresh water is a limited resource • Pollution makes water “dirty”. Procedure: Now the students should come up with some ways to clean the water. Their brainstorming should be listed on the board. The following methods will actually be used: 1. Screening 2. Sedimentation 3. Filtration 4. Chemical Treatment Students may have to be led to examples of some of these answers. Their brainstorming should be grouped then, under the four categories above, which can then be introduced as vocabulary. Then, form the students into four-five teams. (Four works well, as there are four different cleaning methods). Have each team decide which cleaning methods they will use, and in what order. With help, have the students perform the following activities if they chose these methods: 1. Screening: Filter some of the polluted water through a household strainer. Ask students for observations as to what pollutants this cleans (large particles). 2. Sedimentation: Take the screened water and let it settle. More impurities should settle out. Again, students should observe that this removes smaller but clearly visible dirt particles. 3. Filtration: The following items should be added into the filtering tube or funnel. First, a piece of filter paper. Then, one layer of charcoal, then one layer of sand, and then one layer of pebbles. Observations should be made by the students. Explain to them what each of the “filters” is. See if they can figure out why they are placed in the order described above. (Answer: The water should hit the “bigger” filter first, and get out larger particles, and then be refined at each step, until finally hitting the filter paper). Smaller dirt particles which were not removed by earlier processes should now be removed - the water should look clearer. 4. Chemical Treatment: Since this process does not make a visible change, the following activity can be done. Give each group a Petri dish with three small slices of boiled potato in each dish. Onto one slice a drop of the polluted water from the tank should be placed; onto a second slice a drop of the filtered water from the filtering funnel should be placed; onto the third potato slice a drop of the filtered water and a drop of chlorine mixed with this filtered water should be placed. Cover the dish and allow for bacterial growth for a few days. Students can now compare the chemically treated water to the filtered, and to the most impure water. Ask students what they saw when the water was cleaned by each process. Remind them that doing this in reality is expensive and time-consuming. Although we can clean up polluted water, we don’t want to have to. Lead this into a discussion of what human processes pollution comes from and what we could do to keep water from getting polluted. Target Revised Model: • Pollutants make water dirty, but it is possible to clean it. • Pollutants are often caused by things humans do, and we should try to minimize these things. • This is especially important since there is not very much fresh water on earth. Summary: There is a very limited amount of drinkable fresh water in the world. This water can be made unusable if it becomes contaminated or polluted, usually by humans. The water can be cleaned, but that this is very expensive and time consuming. Polluting the water should be avoided as much as possible. Clean It Up - Water Pollution Group Members: Materials Manager: ______________________ Recorder: _______________________________ Presenter: _______________________________ Teacher Liason: __________________________ Your group may choose up to four of the methods to clean your water. The materials manager will gather the necessary supplies and return them. The recorder for your group must record the method(s) used, the cost, and the time it took to clean your water. At the end of the class, the jars of water will be ranked from cleanest to dirtiest. Record your ranking. Your presenter will tell the class which methods you used, and describe whether the method was effective and cost efficient. If you have questions, only the teacher liaison may ask the teacher for help. The order we chose to clean our water was: 1. __________________________________ 2. __________________________________ 3. __________________________________ 4. __________________________________ Method Cost Time Effective? How?