Hands-on Activity: The Dirty Water Project
Educational Standards :
Learning Objectives (Return to Contents)
After this activity, students should be able to:
Materials List (Return to Contents)
Each group should have:
For groups to share:
Introduction/Motivation (Return to Contents)
Due to its incredible chemical properties, water is often considered the "universal solvent." It can mix with organic (natural) or synthetic (man made) substances. Some of these products easily break down in water, while others break down very slowly (or perhaps even never). Water naturally cleans itself through filtration through the ground and evaporation in the water cycle.
At one time, society just disposed of its waste and garbage directly into lakes, streams and oceans. Now, most countries require that if water is polluted, it be treated before it is allowed to enter into natural water formations (lakes, rivers, oceans, etc.).
Generally, there are three ways that raw sewage (waste) water is treated before it is released. First, the liquid is allowed to settle and then is exposed to oxygen by stirring or bubbling air through it (aeration). This allows many harmful organic pollutants to react with the oxygen and change into carbon dioxide and water. Second, the liquid can be filtered to remove the particulate matter. Lastly, the solution is treated chemically (with chlorine or ozone) to kill any remaining harmful things like bacteria.
Environmental, chemical and civil engineers work to improve existing water treatment systems and design new ones to ensure that we have clean water both now and in the future. Today, we are engineers working for the Clean Water Environmental Engineering Company. The company has been asked to design a new water filtration system for a small community with a polluted water supply. We are going to focus on the second step in the water treatment process, filtering. First, we are going to look at different types of filter material to determine which ones work well. Then each group in the company will design a filtering system to clean up the polluted water. The best filtering system will be used in the small community.
Procedure (Return to Contents)
Before the Lesson
With the Students
Attachments (Return to Contents)
Safety Issues (Return to Contents)
Remind the students that when they are making observations they should only use sight and smell; they should never taste the solution, even if it looks "clean."
Troubleshooting Tips (Return to Contents)
Be sure to have paper towels/rags on hand in-case spills occur.
Consider any students' allergies before creating the dirty water sample.
Help the students to fold the filter paper correctly. They will also need to pre-wet the paper so that it sticks to the sides of the "funnel." You may want to have an eyedropper and some tap water available for this purpose.
Remember to dispose of the waste from this experiment properly! Most times the "polluted" water can just be washed down the drain; however, if you have used any chemicals, you will need to dispose of it according to proper disposal methods.
Assessment (Return to Contents)
Pre-Activity Assessment: Part 1
Picture Drawing: Ask each student to draw a picture of their group's "polluted water" in the space provided on their Data Collection Worksheet.
Prediction: Ask students to write down a prediction for what they think their particular filter material will do in the space provided on their Data Collection Worksheet.
Recorded Observations: Ask students to stir the solution and record their observations on their Data Collection Worksheet.
Pre-Activity Assessment: Part 2
Picture Drawing: Ask the students to draw a picture of their best water filter in the space provided on the Data Collection Worksheet.
Activity Embedded Assessment: Parts 1 and 2
Recorded Observations: Students should observe and record what happens during the filtration process.
Picture Drawing: Have students draw a picture of the filtered water in the space provided on their Data Collection Worksheet.
Post Activity Assessment: Part 1
Data Recording: After all the groups have collected their data, share the results as a class (fill in the information on the transparency or chart you made earlier). Students should record all groups' results in the Class Data Section on their Data Collection Worksheet as well.
Clean Water Environmental Engineering Company Design Project: Ask students to work in their engineering design groups to design the best water filter system given the filter choices and a choice of aerated or non-aerated water. There is space provided on their Data Collection Worksheet for them to record and explain their choices.
Post Activity Assessment: Part 2
Worksheet: Have students complete the discussion questions on their Data Collection Worksheets and compare answers with a group member.
Engineering Presentations: Ask each group to present their filter system to the class. Have a class vote and discussion about which water is the cleanest and why.
Activity Extensions (Return to Contents)
Have students use pH paper and a pH guide to help them determine the pH of the solution during different stages of the process (plain water, "polluted water" before treatment, after aeration, after filtering with one filter, and after using their final filter). Discuss how the different items in the solution affect the pH. How would the pH of the solution affect the rest of the environment? (Refer to pH table.)
Ask students to measure the volume before and after filtration. Younger students can describe it as more or less or even use measuring spoons/cups. Older students can use labeled beakers or graduated cylinders.
Try some simple chemical treatments. For example, adding chlorine to a water sample, etc. These may be better done as demos or with older students. Do not forget protective equipment when handling chemicals!
Ask the students if they think that the order of the layers matters. Why or why not?
Ask students to filter their sample more than once. They should keep a small sample after each filtration for comparison. Does the water get cleaner on subsequent filtrations? Why or why not?
Activity Scaling (Return to Contents)
For 3rd grade students, try this activity as a demo with only a couple of filter choices. Do each filter type individually and then ask the students to predict what will happen when you use both of the filter types together. Ask the students to draw pictures of the results.
For 4th grade students, do the activity as is.
For 5th grade students, groups can work a bit more independently so more time should be spent on the design piece. Ask students for their own suggestions for filters and other ways to treat the "polluted" water. Have students bring in some things from home to test as filters and have each group test their own items after you have modeled the filtration procedure.
References (Return to Contents)
Cole, Joanna and Relf, Pat. The Magic School Bus – Wet All Over: A Book About the Water Cycle, New York, NY: Scholastic Inc., 1996 (ISBN 0-590-50833-4).
Glencoe Science: An Introduction to the Life, Earth and Physical Sciences, Student Edition, Blacklick, Ohio: Glencoe/McGraw-Hill, 2002.
Hassard, Jack. Science as Inquiry – Active Learning, Project-Based, Web-Assisted, and Active Assessment Strategies to Enhance Student Learning, Tucson, AZ: Good Year Books, 1999 (ISBN 0-673-57731-7).
Lucas, Eileen. Water: A Resource in Crisis, Chicago: Children's Press, Inc., 1991.
Prentice Hall Science. Ecology Earth's Natural Resources Activity Book, New Jersey: Prentice Hall, Inc., 1993.
Spurling Jennett, Pamela. Investigations in Science – Ecology, Westminster, CA: Creative Teaching Press, Inc., 1995.
Stille, Darlene. The New True Book – Water Pollution, Chicago: Childrens Press, Inc., 1991.
ContributorsAmy Kolenbrander, Jessica Todd, Malinda Schaefer Zarske, Janet Yowell
Copyright© 2005 by Regents of the University of Colorado.
Supporting Program (Return to Contents)Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Acknowledgements (Return to Contents)
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.