How Clean Is Our Tap Water?

Activity 1: Would I recognize pollution?

Could you recognize polluted water? Yes, if it is really badly polluted. But what if it just has some trace elements like cadmium or lead or mercury? How much pollution is detectable?

Materials:	1 bottle of food color
	10 test tubes
	1 test tube rack
	2 pipettes

Step 1: Using the first pipette, add 10 drops of food coloring to the first test tube

Step 2: Using the first pipette, take one drop from the first test tube and add it to the second test tube. Using the second pipette, add 10 drops of distilled water. If the food coloring is the pollutant, is it still visible in a 10:1 ratio? Probably.

Step 3: Using the first pipette, take one drop from the second test tube and add it to the third test tube. Using the second pipette, add 10 drops of distilled water. If the food coloring is the pollutant, is it still visible in a 100:1 ratio? Probably.

Step 4: Using the first pipette, take one drop from the third test tube and add it to the fourth test tube. Using the second pipette, add 10 drops of distilled water. If the food coloring is the pollutant, is it still visible in a 1000:1 ratio? Hmmm….maybe.

Step 5: Using the first pipette, take one drop from the fourth test tube and add it to the fifth test tube. Using the second pipette, add 10 drops of distilled water. If the food coloring is the pollutant, is it still visible in a 10000:1 ratio? If it isn’t visible is it still dangerous? Continue until you have used all 10 test tubes.

Step 6: continue with the dilutions until the tenth test tube is used. Now you have diluted the pollutant (food coloring) so that it is one part per million. Are there any pollutants that are dangerous to this level? When could you no longer detect pollutants? Are there pollutants that are dangerous at those levels? Do research to find out the effects of lead poisoning and cadmium poisoning.

Activity 2: Which water looks and smells better?

Materials: variety of bottled and local waters

Step 1: Set out unlabeled bottles of water and have students analyze the contents based on looks and smell. Which do they think would be safest to drink? (Allowing students to drink in a lab setting is considered a no-no by numerous scientists. If you would like them to taste the waters, be sure that the containers are sterile).

Step 2: Which water looked best? Which smelled best? (Which tasted best?)

Activity 3: How do we get drinking water?

Step 1: Call your local utility company and ask if it would be possible to take students on a field trip to where drinking water is treated. Discuss with the company the source of drinking water for your community and how it must be treated to meet federal safe drinking water standards.

Step 2: If the company allows field trips: assign the students a project that requires them to ask a minimum of 3 higher order thinking skills questions concerning the source of water and how that water is treated for your community.

Step 3: Take the field trip if possible. If not possible, have a spokesman for the utility company come to the class to answer questions.

Activity 4: Where does the bad water go?

Step 1: Call your local utility company and ask if it would be possible to take students on a field trip to a water treatment plant. Discuss with the company the ultimate depository for the treated water after it leaves the plant, the laws that govern the running of the plant, the problems that arise from running such a plant.

Step 2: If the company allows field trips: assign the students a project that requires them to ask a minimum of 3 higher order thinking skills questions concerning the treatment of wastewater in your community.

Step 3: Take the field trip if possible. If not possible, have a spokesman for the utility company come to the class to answer questions.