By: Rachel Hughes

Time: 1 class period
Prep Time: 15 minutes
Materials: Article
3 empty, clean water bottles
Clean glasses at least 3
Yellow food coloring
A handful of dirt


Turn the faucet on and you get water. In the United States most of us take for granted that this water is safe to drink, and it is. Generally, the water coming out of our faucets is covered by the Safe Drinking Water Act, which the United States Environmental Protection Agency oversees. This lesson starts with students being pushed to question how they know that their drinking water is safe. Then, following a discussion about what might be in their water and who is responsible for monitoring water standards, students review a news article that addresses the ability of water utility companies to comply with a new EPA standard. It is an opportunity for students to critically read what the article tells them and what they still need to find out by themselves.

Students will:
1)Identify questions they need to answer to comprehend a specific news article.

National Science Education Standards
Content Area D: Earth and Space Science

Teacher Background

Related and Resource Websites

Original Article: http://www.azstarnet.com/sn/printDS/106481
Contaminants monitored http://www.epa.gov/safewater/mcl.html#mcls



Prior to class:
Collect three clear, CLEAN plastic water bottles. Prepare each of the bottles in the following manner:
Bottle 1 Fill with tap water and a few drops of yellow food coloring. The water should be obviously yellow.
Bottle 2 Fill with tap water and add two teaspoons of salt to bottle. Dissolve the salt fully.
Bottle 3 Fill with tap water and add enough clay, soil, or sediment to make it cloudy.

1. On the board write the following question: “How do you know that the water you drink is safe to consume?” Students should respond to this question in their notebooks.

2. Once students have finished responding to the warm-up question direct their attention to the front of the classroom where you have the three bottles of water and 3 glasses. Pour a little water from each bottle into a glass. Ask students which glass they would prefer to drink from. Ask for a volunteer to drink from the clear water. Students should not know that it includes salt. Then the teacher should sip the yellow water. Once the teacher has demonstrated that the yellow water is all right to drink a student volunteer may also sip it. NO ONE should drink the cloudy water. Ask students what factors were their choices based upon.

3. Once students have mentioned clarity and color of water, ask them if that was enough to distinguish which water was the most palatable. The answer is obviously not. Open the discussion to establish what other factors must be included. Make sure that the lack of any obvious smell, look, or taste does not mean the water is good. Can the students give an example of a water contaminant that would not be tasted, smelled or seen by the use of their five senses alone?

4. Ask students who is responsible for making sure that the water out of the tap is drinkable. (There are multiple correct answers to this question. Some students may receive their drinking water directly from a private well, others from a water utility company.) Students probably do not know who takes care of their water. If they have done the previous big idea cycle this will merely be a review.

5. Explain to students that by providing water through pipes to a certain number of houses, a water utility company is responsible for following the standards laid out by the Safe Drinking Water Act. The Safe Drinking Water Act was established to protect the quality of drinking water in the U.S. This law focuses on all waters, below or above ground, actually or potentially designed for drinking use. The Act authorized the Environmental Protection Agency to establish safe standards of purity and required all owners or operators of public water systems to comply with these health-related standards.

6. On an overhead share with students the “Water arsenic still too high as deadline approaches” article. If you can find an appropriate article for your part of the country you might want to exchange it. Cover up all but the title. Ask students what they know about arsenic. Explain that this article is about arsenic in drinking water and their purpose in reading this article is to identify what questions they need to answer before they can understand the article, specifically the scientific background.

7. Reveal the first paragraph, “Just one month before…” allow students to read it by themselves, or start students reading out loud to their classmates. What questions does this first paragraph prompt? Ex. What is arsenic? Why should we care if there is too much in the water? What are federal standards? Why do we have federal standards for arsenic? Why does Arizona have too much arsenic in the water? Students should write their questions down. You should collect these questions on the overhead also.

8. Continue with each paragraph. Some paragraphs will prompt a few questions. At the end of the article make sure that all the questions are displayed clearly.

9. Once the class has finished, have the students work in groups to identify which questions have been addressed within the article and which ones remain and which ones need more information before they can be answered.

10. Ask students if it is important to know whether there is arsenic in their water. Do they know whether there is arsenic in their water? Explain that in the next lessons they will be exploring the topic of arsenic in drinking water and should at the end of those lessons be able to answer all the questions that they came up with.


Embedded Assessment

Much of this lesson is to assess students’ prior knowledge and to shape the set of learning experiences that follow to best suit students’ needs.

1. Students’ prior knowledge about water quality standards can be assessed by their responses to the ‘warm up’ question, “How do you know that the water you drink is safe to consume?” and the questions that they develop in response to the first few paragraphs of the article.

2. Students’ prior knowledge about arsenic might also be assessed in the questions they develop.

PULSE is a project of the Community Outreach and Education Program of the Southwest Environmental Health Sciences Center and is funded by:

NIH/NCRR award #16260-01A1
The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award


Supported by NIEHS grant # ES06694

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Last update: November 10, 2009
  Page Content: Rachel Hughes
Web Master: Travis Biazo