Objectives:
Students will:
- evaluate that just because water looks clean does not mean that it is, there are pollutants that we cannot see but are present.
- analyze the challenges of managing water systems
Materials:
- 1 gallon distilled water or milk jug filled with tap water
- 1 empty and washed gallon milk jug
- Salt or sugar
- Grease pencil or washable marker
- Cups so that each student has 2
- Copy of attached story Part 1
Procedure:
Before
class, add salt or sugar to one of the gallons of distilled water and
make sure that you can taste it, but that it is all dissolved and not
visible.- Fill the other jug with tap water.
- Label the jugs A and B
- Ask one of the students to read Part I of the attached story.
- Pass out 2 cups to each student and have them label the cups A and B. Have the students pour a small amount of the A jug into their A cup and a small amount of the B jug into their B cup. They should have enough to swallow.
- Have the students inspect the water and see if they can tell any difference. Let them know that they are going to taste the water but it will not be harmful (VERY IMPORTANT! Tell them NEVER to taste something if they don't know what it is. You have set up the experiment and have prepared the test so you know exactly what is in the jugs. Repeat this information!!!!!)
- Have them sip from both of the glasses. Did their guesses match what they tasted? Was there a taste to either glass of water? Did it look like there would be?
- Ask a student to read Part 2 of the story. Encourage further discussion.
Discussion:
What
does this experiment tell you about our drinking water?- What do treatment facilities have to do to water to make it safe and look clean?
- How would this apply to noticing if there were harmful pollutants in the water?
- Is pollution always mucky and brown?
- Will taste always reveal pollution as it did in this experiment?
- What might happen to a person who consumes drinking water over a long time that contains contaminants they are unaware of? Has this ever happened?
- How do you know your drinking water is safe?
This activity is available as an Adobe PDF.
Pollution