SLC #17B - Water Pollution 5 th Grade Meghan Knapp/Trent Grove. References: Slightly Modified from Mary Gilstrap s Water Pollution lesson. www.iit.edu/~smile/bi8701.html - This was the source for the lesson plan, which was modified from the outline presented in this website. http://www.epa.gov/waterscience/kidsstuff/drops2.pdf - Fun activities for pollution and water treatment 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 long necked glass funnel) Funnels for each group (Cut the top off of a 2 liter soda bottle). Large glass tank or jar (Use the bottom part of the soda bottle). Bag of charcoal pebbles, sand, and gravel - from a fish store Micropore filter paper (Coffee filter) Chlorine A strainer (like from your kitchen), or screening (fish net) 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. Lemon juice, vanilla, dish soap all go through the filter Large objects, dirt, and corn starch are mostly caught by the filter Vegetable oil is filtered somewhat, but visibly comes through. Could be the charcoal, which collects some organics, or just that oil is on top, so it coats the rocks and what-not. Food coloring is a good substitute for bacteria. You can show the kids how some things can get through the filter, so even if the water looks clean, it may still need to be treated.
Initial Demonstration: Place rocks, dirt, sand in the bottom of the tank/soda bottle. Fill the tank with water, allowing some of the dirt to mix in the water. Potting soil is good for this, because some of it floats. Ask the students where do we get our water from? They may say the faucet or water plant, but lead them to natural sources like rivers, wells, or reservoirs. Show them the tank of water and ask them if the water is clean. Seeing the dirt they will probably say no. Ask the students if the water is polluted. Water is not polluted just because it has rocks or dirt in it. Pollution is only things that do not belong in water, and these things belong in the water in a pond or a lake. However, we don t want to drink these things, so they do need to be cleaned out. Target Observations: Dirt and rocks can make water look cloudy or dirty. Target Model: Even unpolluted water from a lake or a river needs to be cleaned before we use it. Procedure: Ask the students what things can cause water to become polluted. Major things you should look for are litter, factories, and household items. Add a sample or substitute for each of these items to your tank. For example, use vegetable oil for motor oil, or corn starch for chemicals. As you add the items, point out that some items float, some sink, and some mix in with the water. Each of these things can be removed from water in different ways. Target Revised Model: Household items that we put down the sink can also make our water dirty or polluted. Factories and businesses that dump waste into water also make them polluted. Some kinds of pollution mix in with the water, others stay separate and float or sink. Pollution is caused by everyone, not just factories. Water needs to be cleaned up before we can drink it. Different kinds of pollution can be cleaned up in different ways.
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, each of these methods should be demonstrated. 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 dirt particles. 3. Filtration: The filtering funnel should be layered from top to bottom in the order: one layer of pebbles, one layer of sand, and one layer of charcoal. A long stemmed funnel lined with filter paper should be placed below the layered filtering funnel to further filter the water. Of course, observation should be made by the students. 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. Groups of Students should select up to two methods they believe will work well. Each group will receive an evaluation sheet. They will choose methods that will be cost effective. Once the sheet is complete, the materials manager should gather supplies necessary for the process. Each group should receive a jar of the dirtied water, so that they are all getting the same stuff. The students should time how long it takes for their methods to work, and calculate the total cost of their methods. The clean water should be placed at the front of the room. With 10 minutes remaining in class, the jars should be placed in front of the class and ranked from dirtiest to cleanest. (Obviously, the chemical treatment will not be evident at this point)
Starting with one extreme (cleanest or dirtiest), have the presenter tell the class what method they used, the cost, and the time it took. They can also explain any extenuating circumstances. Students should note what methods were best at cleaning the water. Ask the students if they can see how clean the water is of chemicals and germs. Set up the potato test for germs, or use a chemical test kit to test for poisons. Students should record their findings in their journals. Target Revised Model: Pollutants make water dirty, but it is possible to clean it. Different kinds of cleaning work on different kinds of pollutants. Different methods of cleaning water may be cheaper or more expensive, or take more or less time. Sometimes more than one method of cleaning is used. Pollutants are often caused by things humans do, and we should try to minimize these things. Summary: Water can be polluted in many ways, most of which are caused by humans. We should avoid contaminating the water whenever we can because in order to be drinkable, the water needs to be cleaned, which takes time and can be expensive.
Cleaning Water Evaluation Sheet Group Members: Room Date Materials Manager: Recorder: Presenter: Teacher Liaison: Method of Cleaning Screening Sedimentation Filtration Chemical Treatment Cost $100.00 (installation, labor, and facility) $10.00 (labor and facility use) $500.00 (materials, labor, and facility) $100.00 (materials and safety) Your group may choose one or two methods of cleaning 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. Methods Selected: Cost Time for Purification: Total Rank of Cleanliness: In your science journal, describe your purification process. Use complete sentences. Based on the class results, what method(s) do you believe is the best for purifying water? Explain your answer. Did all members of your research team contribute to your project? By signing below you agree that everyone participated, and that you also did your part to help the group.