Make your students water-wise.

Although water makes up three quarters of our planet, water for human and wildlife uses is a limited resource and must be managed wisely. As our country's water use flows faster than our ability to recycle the water naturally, waste-water management is crucial. The following exploration will give kids a fun and effective wake-up call about water conservation.

WARM-UP ACTIVITY

Have kids list various places water is used, such as homes, schools, farms, and factories. Then have groups of students choose one of the categories and brainstorm a list of how water is used in these places. Emphasize that industry uses more water than any other domain.

SAVING GIL THE GUPPY 

Concepts: Waste-tainted waters contain less oxygen. Wastewater must be treated, or purified, before it can be used again.

Skills: observing, predicting, comparing and contrasting, making conclusions

Materials (for an all-class activity): 1/2 cup rotting organic matter (see below), a resealable plastic bag, rubber gloves, water plants (2 strands of elodea or water hyacinth, or a handful of duck weed), a fishbowl or aquarium, 2 guppies, guppy food, 2 pint-size jars, 2 paper cups, 1 small box of activated charcoal 

PREPARING THE ACTIVITY

Two weeks before: Put about 1 cup vegetable and fruit leftovers in a resealable plastic bag and let it decompose. The smellier the better!

The day before: Purchase water plants, 2 guppies, guppy food, and some activated charcoal from a pet store - it shouldn't cost more than about $7 total. Ask the salesperson how to care for the guppies.

* Put the guppies in an aquarium or fishbowl in your classroom.

* Fill the two jars three-quarters full with tap water and let them sit overnight to dechlorinate.

DIRECTIONS

Day One

1. Label the jars A and B.

2. Ask a volunteer to put the plants in jar A. Wearing gloves, another volunteer pours the organic matter into jar B. Place the jars out of direct sunlight and away from radiators so the water temperature remains between 60 and 70 degrees F. Let jars sit for one week.

Day Eight

1. Have kids put a guppy in each jar and observe the guppies' behavior. Ask kids: Does either fish appear to be stressed - breathing rapidly or with difficulty? After no longer than five minutes, return both guppies to the aquarium or fishbowl.

2. Ask kids to think about what they observed. What caused the guppy to feel stressed? (Lead students to realize that fish get oxygen from the water. If they do not get enough oxygen, which is the case with the guppy in jar B, they will become stressed and die. Polluted water often has low levels of dissolved oxygen in it. Dissolved oxygen is essential for a healthy body of water.)

3. Ask students: What do you think would happen if wastewater, like the water in jar B, continually flowed into a stream? (Wastewater, or polluted water, can completely remove dissolved oxygen from an otherwise healthy stream.)

4. Have a student use the tip of a pen to poke a hole in the bottom of a paper cup. Let another student be in charge of filling the cup halfway full with activated charcoal. Ask students to predict whether the charcoal will help filter, or clean, the water in jar B.

5. Holding the cup above an empty paper cup, slowly pour about half the water from jar B into the charcoal-filled cup. Let children examine the filtered water.

6. Ask kids to compare the water in jar B with the filtered water. Does the filtered water smell different or look different from the water in jar B? Have students draw pictures and describe what they observe.

7. Ask your students to think about what might happen if water plants were added to jar B. Add the plants, then set aside for a week. Are there any observable changes in the color of the water or the appearance of the plants? After one week, add a guppy to jar B. Does the guppy show any signs of stress? (The plants purify the water, so the guppy ought to be breathing easier!)

RESOURCES FOR STUDENTS

* The Magic School Bus Goes to the Waterworks by Joanna Cole (Scholastic, 1988)

* Resources: Water by John Baines (Thomison Learning, 1993)

* For the free poster, How Do We Treat Our Wastewater? write to the U.S. Geological Survey, Books and Open-File Reports Section, Box 25425, Mail Stop 517, Denver Federal Center, Denver, CO 80225-0425.

TECHNOLOGY CONNECTION

Students can explore actual freshwater ecosystems around the world - and learn how to protect them from pollution - with Puddles to Pondwater, a software package that will turn even the most science - shy students into avid biologists MS-DOS [CD-ROM and Macintosh versions in the works]; $59.95; Niad Corp., [905] 470-0866). See "Eco-Kids to the Rescue" in the April 1994 issue of Instructor to observe how one classroom teacher uses this program.

CHATTANOOGA'S LIVING MACHINE

The water that flows out of sinks, tubs, and toilets becomes wastewater and must be treated before it can be reused. About one third of wastewater is filtered through septic tanks or sand filters near people's homes. In more populated areas, wastewater is piped into a wastewater treatment facility. There it is treated with chemicals that break down bacteria and other contaminants, making it safe enough to drink again. Some scientists, concerned that these treatment facilities create a lot of harmful by-products, are now devising water treatments that rely on biological rather than chemical agents to purify the water.

Dr. John Todd, a biologist and president of the Center for

Restoration of Waters at Ocean Arks International in Massachusetts, has developed just such a method - the Living Machine. Four hundred gallons of water circulate through four clear cylinders that each contain a different link in the food chain, simulating the way natural wetlands systems function. Dr. Todd's system has been applied to treat industrial wastewater and damaged watersheds throughout the United States. For example, a sewage plant in Rhode Island uses snails to break down the heavy metals used by costume jewelry makers.

BE A PEN-PAL SCIENTIST

A Living Machine was set up at Lakeside Elementary School in Chattanooga, Tennessee, where students can watch the system in action. Your students can learn more about how the Living Machine works with the reproducible on page 28. if kids have any questions they'd like to ask the students in Chattanooga, have them send their letters to Jo Ann Everett, Media Specialist, Lakeside Elementary School, 4930 Highway 58N, Chattanooga, TN 37416. The students in Chattanooga are eager to correspond with their science pen-pals.