The Urban Resources Initiative (URI) at the Yale School of Forestry and Environmental Studies (F&ES) aims to "Improve the urban environment of New Haven through programs and projects that directly involve community residents, particularly children, for the purpose of improving their lives as well as their environment" (URI n.d.: n.p.). URI-sponsored environmental education programs help advance this goal. Urban public schools often have inadequate environmental education programs. The public school system often lacks appropriate teacher training in environmental education and teachers may not have the necessary skills to develop interdisciplinary lesson plans (Esser 1996). URI has responded to these limitations by providing external specialists in environmental education to supplement inadequate class curricula.

Since 1991, URI interns and Yale F&ES alumna Susan Swensen have engaged in an experiential environmental education program at the Edgewood Elementary School. The model has been expanded this spring to include three other public schools in the New Haven school district. As a student at the Yale School of Forestry and Environmental Studies and a URI intern, I have had the opportunity to guide and participate in this transition.

This paper provides a brief history of the Edgewood Park/ School Project, details the goals behind the Edgewood model and relates the expansion of this teaching methodology to other neighborhood schools. In addition, this paper provides detailed lesson plans so that the Edgewood model can be applied in other urban schools to supplement existing environmental education curricula.

The Edgewood Park/ School Project (EPSP) was initially developed in 1991 by two graduate students at the Yale School of Forestry (Chip Darmstadt and Elana Cohen), along with Yale F&ES alumna Anne Harper as Project Coordinator, and former URI Program Director Barbara Milton. Susan Swensen assumed the role of Project Coordinator spring of the first year and has continued this involvement with the EPSP through fall 1996. The EPSP was designed as a collaborative effort between Yale and New Haven URI, the New Haven public school system, Friends of Edgewood Park, and the New Haven Department of Parks, Recreation and Trees. This interagency association helped improve the relationship between the various participants. Together, these agencies strove to advance environmental education at Edgewood Elementary School through interactive, interdisciplinary and experiential learning.

The seven-month program consisted of biweekly visits to the fifth-grade classes. Students engaged in hands-on experiments, vivid demonstrations, innovative arts-and-crafts projects, and interactive discussions during a classroom visit early in the week. The basic ecological concepts were then explored and reinforced during Friday field trips to neighboring Edgewood Park. Here, students explored basic biological concepts through educational games, field identification, experimentation, water testing and pond sampling. In this way, Edgewood Park served as an outdoor classroom where "science came to life." By supplementing classroom lectures with outside activities, students were better able to relate intangible scientific concepts to the world around them. In turn, the program fostered a connection between its young participants and the environment. Units culminated in a final project designed by the children. The final project was presented to the fourth-grade students, parents, neighborhood residents and park and school officials. This project served as a useful learning tool, both for the participating students and for the younger children who would join the EPSP the following year. The project also helped strengthen the connection between the participating children and the community.

Lessons were instructed by Susan Swensen, a neighborhood resident and frequent Edgewood Park user, along with one or two F&ES student interns. This formula allowed the Edgewood School to benefit from the expertise of the program instructors. Susan’s influence was strengthened, in part, because of her personal community involvement and association with Edgewood Park. Student interns also gained valuable professional experience under her enthusiastic and committed guidance.

The Edgewood Park Ranger, Vinny Lavargna, played an active role in the program by facilitating park projects and field studies. This connection with the Ranger Program improved the credibility of the EPSP. Children benefited from Vinny’s direct experience with the Park. At the same time, Yale F&ES student interns were able to better understand the complexities and rigors of the Parks Department. The EPSP helped the Edgewood Ranger by encouraging public involvement with the Park, providing educational program ideas, and participating in park improvement projects.

Edgewood Elementary was initially targeted as a field site for this program because of its nearness to Edgewood Park along with the strong commitment of the Edgewood fifth-grade teachers, Dorothy Martino and Richard Cavallaro. The program’s originators believed that the physical proximity between Edgewood Elementary and Edgewood Park (less than one block) would in turn engender an emotional closeness to the park, and thus the environment. By connecting the children to a local open space, the EPSP aimed to produce students who would continue to act as park stewards even after the program’s conclusion.

The EPSP has been extraordinarily successful. Students emerge from the program with an academic understanding of the environment and an emotional commitment to the natural world. The program also encourages improved social skills, increased self confidence, positive peer interactions, enhanced critical reasoning and better communication skills (Honigfeld 1994). In 1997, URI decided to introduce the Edgewood education model into other area elementary schools.

Past participants in the EPSP predicted the program’s eventual expansion. In a 1994 working paper, student intern Harriet Honigfeld states, "Those involved in the Edgewood Park/ School Project hope that it will serve as a model for others seeking to use a local park or natural area as an educational or community resource" (30). By involving URI actively in this expansion, URI is able to advance its goal of community education and neighborhood improvement.

In its trial year, URI targeted three schools that triangulate Beaver Ponds park (Beecher, Helene Grant and Jackie Robinson). Each of the fifth-grade teachers at these schools was given the option of participating in a two-week pond ecosystem unit. These schools were selected as a response to strong community interest in increased environmental education opportunities (esp. from Friends of Beaver Ponds Park). The program specifically targeted schools that were fairly close to Beaver Ponds in order to help foster a sense of stewardship from student participants. There are many schools that would benefit from the education experience; however, these three campuses include students from the three neighborhoods surrounding the Ponds: Beaver Hills, Dixwell and Newhallville. URI believed that this would maximize its outreach and potential influence.

The EPSP was created because of a strong belief that environmental education for young children would engender a life-long commitment to the environment. Although there was some concern about the education potential of a two-week, rather than seven-month program, evidence suggests that short-term programs can still be influential. Esser (1996) cites a Jaus (1984) study which found that third graders who had engaged in only 10 hours of environmental education revealed a stronger environmental ethic than fifth-grade children who had not. A later Jaus study revealed that fifth-graders who participated in a fifteen-consecutive-day environmental education program had significantly higher environmental attitudes (22-percent higher) than a control group. Jaus’ studies provide support for the benefits of short-term environmental education.

The pilot program includes four modules about pond ecosystems: "How We Live Where We Live" (habitats and adaptations), "Ecosystem Interactions," "Water Quality," and "The Pond Through Time" (succession and annual changes). Susan Swensen and Jennifer Yelin (1996-97 F&ES student intern) felt that these units would allow students to learn about a neighboring ecosystem and engage in hands-on fieldwork, while still learning about fundamental ecological concepts. Thus, students participating in the "Ecosystem Interactions" unit would learn specific facts about pond communities and ecosystems; however, they would also learn about environmental concepts that are applicable to any ecosystem (e.g., food webs, the human role in the natural environment). In this way, the two-week program would provide a foundation for a better understanding of the natural world.

Because of limited time, teachers were initially limited to two modules. Each module consisted of a one-hour classroom session followed by a one-and-one-half hour outdoor lesson at Beaver Pond. Thus, each teacher initially committed to a five-hour environmental education program. Although the program was first scheduled to be semiweekly, Susan later offered to teach an additional one-hour weekly class session so that students could participate in all four classroom modules, coupled with two outdoor sessions. This scheduling change was proposed because program organizers believed that all four lessons were necessary for the children to understand the wide-ranging applications of the curricula.

The program took three months to develop and publicize. It was actually implemented in April and May. Initial telephone contact to school principals, followed by an explanatory letter and brochure was made in early February (see Appendix 1). Fifth-grade teachers were contacted to assess their interest in the program in the ensuing weeks. An orientation meeting with the participating teachers to clarify our expectations and demands was held mid-March at Beecher Elementary School (see Appendix 2). Classroom visits were scheduled to begin in early April and continue through mid-May. Teachers completed a brief evaluation form following each unit (see Appendix 3). The New Haven Riverkeeper, Peter Davis, was the Parks Department liaison for the program. Peter assisted with pond measurements and educated students about the pollution of New Haven waterways. Children benefited from his commitment and personal experience with Beaver Ponds.

In her six years at Edgewood Elementary School, Susan Swensen has tested and perfected hands-on, interactive, interdisciplinary lessons. The activities are a combination of existing environmental education curricula and Susan’s innovative ideas. To facilitate the EPSP transition, Susan and I divided these activities into four discrete units: Ecosystem Interactions, How We Live Where We Live, The Pond Through Time, and Water Quality. Lesson plans for these modules were created so that teachers that have participated in the program may be able to repeat activities in future years. This guide will also be useful for future student interns who will help implement the pond life program. Each module includes detailed background information and clear instructions for every activity. The four modules may be taught as a month-long unit or as independent mini-units. We recommend that all students receive at least a brief overview of ecosystem interactions to foster a better understanding of the individual’s role in the natural world. The four modules follow.

The lessons in this unit focus on communities and ecosystems and the interactions within them. In order to instruct this lesson, teachers will need a general understanding of these concepts.

A natural community includes all of the living components (plants and animals) that live together in one place and the interactions between them (leap grade 3). Natural communities can be many different sizes. For instance, a decaying log is a community, as is an entire pond, or a plot of forest land. The components of a community interact in many ways. In this unit, we want to emphasize the transfer of energy between component parts of the community. Energy is transferred through a food chain.

Plants are producers; they gather energy from the sun to create their own food. They are the only living thing that can convert the sun’s energy directly. Other members of the community gather energy from plants either directly (by eating them), or indirectly (by eating other animals that eat plants). Animals that get their energy directly from plants are called herbivores. Carnivores eat other animals to get their energy. Omnivores are able to eat either plants or animals. Insectivores are a special type of carnivore that eats only insects. Decomposers (e.g., bacteria, mushrooms, snails) get their energy by breaking down dead plants and animals and converting them into soil. This allows the process to begin again.

Energy cannot be recycled. Thus, all of the energy we use originates with the sun. The interactions along the food chain illustrate the transfer of energy through the community.

An ecosystem includes the living and nonliving things that exist in one place and their interactions. A pond ecosystem, for example, includes the air, water, dirt and rocks, along with all of the living organisms discussed earlier.

Because everything in nature is so interconnected, anything that is done to one part of the system can affect the other components. For instance, a squirrel may bury an acorn; an oak tree may grow in its place; and leaves from the tree might fall into a neighboring pond. The pond may then fill in completely and disappear. Often, the things we do to the system may backfire and negatively affect human beings. For instance, a farmer may spray a pesticide on his fields. Rainwater may wash this chemical into a neighboring river. The pesticide may attach to passing algae. The algae is consumed by a small fish, which is eaten by a larger fish. Ultimately, the same farmer may eat the contaminated fish -- and be injured by the same pesticide he applied to his fields to help the crops grow better!

The activities that follow will better explain these concepts.—

• Ingram, Mrill. Bottle Biology (Dubuque, Iowa: Kendall/ Hunt Publishing Co.) 1993, page 111.
• LEAP (Learning About Plants) Grade 3 Curriculum (Ithaca, NY: Cornell Plantation) 1991, Unit I (available through Harvard University’s Arnold Arboretum; Jamaica Plain, MA).
• LEAP (Learning About Plants) Grade 5 Curriculum (Ithaca, NY: Cornell Plantation) 1991, Unit I IV (available through Harvard University’s Arnold Arboretum; Jamaica Plain, MA).
• James, Charles C. The Carnegie Academy for Science Education (Washington, D.C.: Carnegie Academy for Science Education) 1995, pages 25-26.
• Sheehan and Waidner. EarthChild (Tulsa, OK: Council Oak Press) 1991, page 34.

TITLE: Community Discussion (leap grade 3 page 2)

OBJECTIVES: Students will understand the difference between human communities and natural communities. Children will learn about the transfer of energy through a community via food chains.

METHOD: Interactive discussion

MATERIALS: None

TIME: 10 minutes.

• Begin by having the students identify human communities.

Ask the children what their community is. Who lives there? Where is the community located? Does it have a name? How do members of the community interact?

(Children will name their neighborhoods. Teachers, mothers, doctors, students and secretaries live there. The teachers teach the students. Mothers take their children to the doctors.)

• Natural communities are made up of the plants and animals that live together in one place.

Ask the children to think of examples of natural communities.

(ponds, forests, rivers, fields, decaying logs, etc.)

Ask the children to think of all of the living components of a pond community.

(algae, pond lilies, cattails, dragonflies, tadpoles, frogs, mallard ducks, herons, sunfish, bass, etc.)

Write their answers on the board.

Ask how these things interact with one another.

(A heron eats a fish. A tadpole eats the algae. Dragonflies eat other insects.)

• In a natural community, living things transfer energy by eating one another.

Tell the children about the different components of a food chain. Define producers, consumers (herbivores, carnivores, omnivores, insectivores) and decomposers. Explain that plants are the only living thing that can capture the sun’s energy to make food. We all rely on the energy from the sun.

Tell the children that there are different categories of consumers in a food chain. A primary consumer eats plants; a secondary consumer "eats the animal that ate the plant"; a tertiary consumer eats "the animal that ate the animal that ate the plant."

Ask the children if they are producers, consumers or decomposers (consumers). Are they herbivores? Carnivores? Omnivores?

Ask the children which of the members of the pond community are producers? Which are consumers? Which are decomposers? Make a list.

(Algae, pond lilies, pond weeds, and other water plants are producers. Birds, diving beetles, damselfly nymphs, dragonfy nymphs, ducks, frogs, tadpoles, water scorpions, etc. are consumers. Snails, scavenger beetles, scuds and bacteria are decomposers.)

Ask the children to think of a sample food chain.

Draw the chain on the board with arrows indicating the flow of energy. Examples include sun --> plants (producer) --> caterpillar (herbivore) --> shrew (insectivore) --> owl (carnivore) --> mushroom/ bacteria (decomposer); grass --> rabbit --> fox; seeds --> quail --> bobcat; grass --> grasshopper --> mouse --> owl; leaves --> caterpillar --> bird --> snake --> hawk.

TITLE: Putting Together the Pieces (earth child 34)

OBJECTIVES: Children will be able to understand energy transfer and the different components of the food chain by assembling their own chains.

METHOD: Arts-and-crafts project.

MATERIALS: Half-inch strips of colored construction paper, one color for each category: producer, primary consumer, secondary consumer, tertiary consumer, decomposer and nutrients. Label the different strips with different plant and animal names. Paste or glue. Colored chalk.

TIME: 15 minutes.

• Each child will create a food chain showing community interactions.

Give each child six colored strips. The strips should list plant and animals that are dependent on one another. For examples, see attached list.

Children will put paste on one end of the producer strip to form a ring.

Pass the primary consumer strip through the ring and form an interlocking loop.

Continue through the entire food chain.

• Discuss the different chains with the children.

Ask the children how the colors are ordered in their chains.

Ask some of the children to read their chains.

Write their answers (color-coded) on the board.

Ask the children what each color represents (e.g., the plant could be green, the primary consumer could be orange, the secondary consumer could be red, the tertiary consumer could be blue, and the decomposer could be purple).

TITLE: Ecosystem Discussion (leap grade 5 pages 5-6)

OBJECTIVES: Children will understand the difference between a community and an ecosystem. Children will be able to think of the component parts of an ecosystem and delineate some of the interactions between them.

METHOD: Interactive discussion.

MATERIALS: None.

TIME: 5 minutes.

• In reality, things do not exist as separated chains.

Ask if any of the children linked their chains into a circle.

Tell these students that they were thinking ahead. Their circles represent the cycles of nature. The decomposer gets its energy by breaking down other plants and animals. This creates soil that can be used to grow new plants.

• Ecosystems include all of the living and non-living things in a place and their interactions.

The linked chains include the non-living component, soil.

Ask the children to think of non-living things in a pond ecosystem.

(mud, water, air, and rocks).

Add these answers to the list of things in a pond community (listed on the board from Activity One).

Explain that by adding non-living items to the list of living things in a pond community, we have created a pond ecosystem.

Ask the children to think of examples of interactions between living and non-living things in a pond community.

(Lily pads float in water. Their roots are anchored in the mud. A frog sits on the lily pad. The frog eats insects in the pond.)

TITLE: The Web Game (the carnegie academy for science education 25)

OBJECTIVES: Children will create a food web to illustrate the multitude of interactions in an ecosystem. Children will come to understand what happens when any part of the web is destroyed.

METHOD: Game.

MATERIALS: Spool of twine. Cards with pictures of different consumers in a food web, one per child (for examples see attached list). Only include one copy of each animal. Additional cards for sun, water, soil, producer and decomposer.

TIME: 15 minutes.

• Set up for the web game:

Place four chairs in the center of the room. Put the sun, water, soil, producer and decomposer cards on these chairs.

Have the children stand in a circle around the room. You may choose to arrange their chairs in a circle.

Hand each child a different animal card at random.

• Energy (the string) is passed throughout the web.

Ask the children what every food chain must start with (the sun). Tie the string to the "sun chair" in the center. Then pass it to the "producer (plant) chair."

Ask the children which of them would eat a plant. Pass the string to that person (animal).

Then, ask which child’s picture would eat that animal, pass the string to that person.

Eventually (after three to four turns), no one else in the room will eat this animal. This is the top consumer. Pass the string to the decomposer (bacteria) chair in the center.

Using the same string, begin a new sequence: soil, sun, producer, herbivore, etc. Many of the herbivores will receive the string several times. This explains why herbivores tend to have so many offspring (because everything likes to eat them!).

• When every child has held the string at least once, ask the children what they have made (a food web).
• Ask the children what the non-living components of their web were (the sun and soil). What was the producer (the plant)? Have the herbivores raise their hands. Now, have the carnivores and omnivores raise their hands. What was the decomposer (the bacteria)?
• Ask the children what would happen if all of the herbivores died? If all of the carnivores died? If all of the plants died?
• SAMPLE POND FOOD WEBS

(the carnegie academy for science education 26)

Here are a number of sample food web combinations. This list will be helpful for Activities 2 and 4. Each web includes the sun, a producer, primary consumers, secondary consumers, and so forth. Bacteria are the decomposers at the end of each food web. They convert the material to nutrients to begin the cycle again.

TITLE: Exploring the Pond

OBJECTIVES: Children will learn about food webs and food chains.

METHOD: Pond sampling and collection.

MATERIALS: Dip nets.

TIME: 45 minutes.

• Children will sample the pond.

The students will use their dip nets to sample the water’s edge and surface film.

Students will place their specimens in large buckets.

As the children collect from the pond, explain that some insects eat one another.

Discuss sample food webs with the students as they collect their samples.

• Students will observe the different specimens.

Sort the insects and place them in magnifying boxes for observation.

Sort the insects into small aquariums.

• Students will create food chains and webs.

Ask the students to separate the producers (water plants), consumers (most aquatic invertebrates, see classroom Activity One) and decomposers (bacteria, scuds, scavenger beetles, snails).

Ask the students to separate the herbivores (diving beetle, tadpoles, water boatman) from the carnivores (damselfly nymphs, dragonfly nymphs, giant water bugs).

Ask the students to line the tanks up into food webs.

TITLE: Ecosystem in a Jar (bottle biology 111; leap grade 5 page 7-10)

OBJECTIVES: Children will learn about natural communities and systems by creating their own pond ecosystem.

METHOD: Pond sampling and collection.

MATERIALS: Two-liter soda bottle (two per child). Snails, various aquatic invertebrates, water plants, soil and pebbles, water.

TIME: 30 minutes.

• Students will learn about the components of an ecosystem.

Ask the children what producers need to stay alive (water, sunlight, air).

Ask the children what consumers need to survive (food, water, space, air).

Ask the children what decomposers need to survive (dead plants and animals).

• Children will create their own pond ecosystems.

Cut the top of a two-liter bottle (1-2 cm above "shoulder" where bottle tapers).

Remove the base from another bottle to use as a lid for the aquarium.

Tell the students that we will be creating pond ecosystems in a bottle.

Give each student a bottle and lid.

Ask the children if this would be an ecosystem if you put water, a diving beetle and a dragonfly nymph in the jar (no, an ecosystem also needs producers and decomposers).

Ask the children how a sealed ecosystem could get oxygen (the plants create it).

Ask the students how sunlight can enter a sealed ecosystem (shine through the jar).

The children will put the following things in their jars: 1) pond plants, 2) a snail, 3) diving beetle or water boatman, 4) dragonfly nymph or damselfly nymph, and 5) pond water.

Cover the bottle with the lid. You may need to seal with masking tape.

Keep the jar in indirect sunlight (direct sunlight can overheat the system).

In this module, children will learn about the different habitats in a pond. Students will come to understand the unique adaptations of different organisms that allow them to live in these different habitats. Students will explore adaptations in coloration, protection, movement, feeding, breathing and reproduction.

The lessons in this unit focus on pond habitats and the organisms that live in them. In order to instruct this lesson, teachers will need a general understanding of these concepts.

A pond is a shallow body of water with a muddy bottom that has rooted plants growing from shore-to-shore. Because the water is so shallow, temperatures are fairly uniform from top to bottom; however, water temperature will change as air temperature fluctuates. (pond and brook chapter 3; golden guide pond life introduction)

The pond is composed of four habitats. A habitat provides all of the things that an organism needs for survival: food, water, shelter, and space (naturescope 42). Thus, a bird’s habitat is not just its nest. Rather, the habitat would include the entire section of the woods where the bird gathers its food, seeks water, builds a nest, breeds, and finds protection from predators. The pond habitats include the surface film, open water, the bottom, and the water’s edge.

The surface film is the habitat of many air-breathing creatures and floating plants and animals. Floating plants have underwater stems and roots, with leaves at the water’s surface. These plants "go with the flow" of the water. Many animals that live on the surface film are able to walk on water because water molecules cling together (i.e., surface tension); thereby, making the molecules stronger than the weight of the insect. Other animals hang beneath the surface film and breathe through a "straw" that extends to the surface of the water. These animals eat floating plants, dead insects that float to the surface, and one another.

The water’s edge is the richest habitat in the pond with the greatest diversity of plant and animal life. Here, organisms easily find light, cover, food and oxygen. Many emergent plants are at the pond’s edge. These plants are rooted in the bottom with their leaves extending above the water’s surface. Their stems are very sturdy to withstand the water’s flow.

The pond’s bottom is generally covered with organic debris from decaying plants and animals. Many animals burrow in the muddy bottom for warmth and protection. Many bacteria of decay also live at the bottom of the pond. These bacteria help cycle nutrients throughout the system. These decomposing materials may eventually fill in the pond. Because light penetration is lowest at the bottom, there is less oxygen in this region. Consequently, the organisms that live here have low oxygen requirements.

Large, free-swimming animals and microscopic, floating plants live in the open water. Turtles, birds, fish and frogs may frequent the open-water area. The open water is the area where plants are no longer rooted in the pond’s bottom. Many ponds do not have a genuine open-water zone, because plants extend from shore-to-shore in shallow water bodies. (Biology is Outdoors 105-107; Golden Guide Pond Life 17-19)

Adaptations are special features of a plant or animal that make it better suited to its environment. There are a multitude of adaptations including variations in color (e.g., camouflage), protection (e.g., stingers), movement (e.g., stream-lined bodies for faster movement), feeding (e.g., a large mouth), breathing (e.g., gills for underwater breathing), and reproduction (e.g., a large number of offspring to withstand predation). Specific adaptations will be discussed in detail throughout this lesson.—

• Allen, Maureen Murphy et al. Critters (USA: Aims Education Foundation) 1989, pages 124-127.
• Aquatic WILD (Boulder, CO: Western Regional Environmental Education Council) 1987, pages 81-82.
• Caduto, Michael J. Pond and Brook: A Guide to Nature in Freshwater Environments (USA: Hanover and London) 1985, chapter 3.
• Dekkers, Midus. The Nature Book (New York: MacMillan Publishing Co.) 1988, pages 64, 67.
• Hancock, Judith M. Biology is Outdoors: A Comprehensive Resource for Studying School Environments (Portland, MN: J. Weston Walch, Publisher) 1991, pages 105-107.
• Hickman, Pamela M. Habitats: Making Homes for Animals and Plants (Reading, MA: Addison-Wesley Publishing Co.) 1993, page 33.
• Imes, Rick. Practical Botanist (New York: Simon and Shuster Inc.) 1990, pages 110-111.
• Lingelbach, Jenepher. Hands-on Nature: Information and Activities for Exploring the Environment with Children (Woodstock, VT: Vermont Institute of Science) 1986, page 64.
• Project WILD (Boulder, CO: Western Regional Environmental Education Council) 1992, pages 114-115.
• Ranger Rick. NatureScope: Amazing Mammals Part I (Washington, D.C.: National Wildlife Federation) 1986.
• Reid, George K., Ph.D. Golden Guide Pond Life (New York: Golden Press) 1987.
• Sisson, Edith A. Nature with Children of All Ages (New York: Prentice Hall Press) 1982, page 131.
• Stidworthy, John. Ponds and Streams (Mahwah, NJ: Troll Associates) 1990, pages 12-17.
• ACTIVITY ONE

TITLE: Introductory discussion.

OBJECTIVES: Students will be able to define a pond and the habitats within it. Students will realize that different organisms have adaptations that enable them to survive in their environment.

METHOD: Interactive discussion.

MATERIALS: Pond habitats poster.

TIME: 10 minutes.

• In this unit, we will study ponds.

A pond is a shallow body of water with plants growing from shore-to-shore.

• Ponds consist of four habitats (surface film, water’s edge, bottom, open water).

A habitat provides an organism with food, water, shelter and space.

Show the children the different pond habitats on the "pond habitat poster."

Ask the children to identify different habitats.

(A bird’s habitat includes its nest, the tree it lives in, and the neighboring plot of land where it forages for worms. A squirrel’s habitat includes the hollow tree trunk where it may sleep, and also the forest where it gathers acorns. A human’s habitat includes a house, the grocery store, and the roads we drive and walk on to get to different places.)

• Different organisms live in different places because they have developed different adaptations to survive in their environment.

Adaptations include variations in color, protection, movement, feeding, breathing and reproduction.

Write these words on the board.

Ask the children to identify the adaptations of some common plants and animals.

How does a rose protect itself? (thorns) What special adaptation do frogs have for movement? (webbed feet) How do fish breathe underwater? (gills) How does GI Joe hide in the woods? (camouflage) How do bears eat meat? (teeth for chewing) How come frogs lay so many eggs? (to have some young survive predation)

TITLE: Amazing Adaptations (golden guide pond life; project WILD 114-115; aquatic WILD 81+; habitats 33; pond and stream 12-15; nature with children of all ages 131; pond and stream 16-17)

OBJECTIVES: Children will learn about the different adaptations of animals in the pond. The students will have a chance to see different organisms through a bioscope to observe the organisms and their adaptations up close.

METHOD: Interactive discussion with flashcards and bioscope. Arts-and-crafts project.

MATERIALS: Large flashcards with photos of the different animals. A bioscope and screen. Aquatic invertebrates. 11 x 17 sheet of paper with a drawing of a pond (one per student). List of habitat types (one per student). Pictures and names of different pond organisms (one list per student). Gluesticks. Scissors.

TIME: 50 minutes.

• Different plants and animals live in different habitats because of their adaptations.

Write the four pond habitats on the board (surface film, water’s edge, bottom, open water).

• The children will create field guides for Friday.

Distribute the large pond picture, sheets of pond organisms, scissors and gluesticks to all students.

Students will paste the name of each habitat to the appropriate place on the pond.

• Students will identify the adaptations of common pond organisms.

Use the flashcards to show the children different animals and have the students try to identify the adaptations.

As the children identify each animal’s adaptations, write its name under the appropriate habitat on the board (to save time, only write the name, not the adaptation).

Students will cut and paste the animal in their field guide (in the appropriate habitat).

Students may draw fish, turtles and ducks in the open water.

At the end of the activity, use the bioscope to show students live specimens. This will help them identify pond life on Friday.

Split the class in half. Half of the students will explore plant adaptations, and half will explore animal adaptations. Students will switch in 15 minutes.

TITLE: Lily Pad Experiment (practical botanist 110+; the nature book 73)

OBJECTIVE: Children will learn how lily pads are able to "breathe in water."

METHOD: Demonstration.

MATERIALS: Lily pad, bicycle pump, rock, bucket, water.

TIME: 5 minutes.

• Plants breathe through tiny holes on the underside of their leaves (i.e., stomata).

Lily pads can’t do this because they would be "breathing in" water (and drown)!

So, lily pads have these openings (stomata) on the upper surface of the leaf.

• Demonstrate how lily pads breathe in water.

--Attach a lily pad stem to a bicycle pump (tape it tightly).

--Place the leaf in a bucket of water.

--Hold the leaf down with a small rock.

--Pump air into the leaf.

--Air bubbles will fill the container, revealing where the leaf emits oxygen.

TITLE: "There’s a Straw in this Hot Dog!" (practical botanist 110+; wetland wonders 94+)

OBJECTIVES: Students will see how wetland plants breathe in saturated soils.

METHOD: Demonstration.

MATERIALS: Pocket knife, cattail.

TIME: 3 minutes.

• Plants need carbon dioxide and oxygen from the air.

Cattails are emergent plants. Thus, their stem and flower extends out of the water.

Plants that live in water-laden soils must transfer these gasses from the air to their roots.

Cattails transfer air through special air conduits (called aerenchyma).

Cut away the surface of the plant’s stalk. Students will be able to see the "straw" inside the cattail stem.

Pass the plant around the group.

TITLE: Gem of the Pond

OBJECTIVES: Students will explore the unique breathing adaptation of jewelweed.

METHOD: Discussion.

MATERIALS: Jewelweed.

TIME: 3 minutes.

• Jewelweed has adapted to its watery environment.

Tiny hairs on the bottom of the leaves glisten like jewels because they catch air.

This helps the plant breathe in its watery environment

Show the children a jewelweed leaf.

Explain that another special feature of jewelweed is its ability to stop the itching of poison ivy.

If the other group is still meeting, have the children discuss other plant adaptations they know about. Students should think about poison ivy (poisonous sap for protection), maple seeds (double-winged airborne seeds, known as samaras, travel far to help with dispersal), roses (thorns for protection). Other plants have a large number of seeds to ensure survival of offspring. Some plants have indigestible seeds so that animals disperse and fertilize them. "Prickly" seeds (burrs) attach to animal fur (and human’s clothing) for easy dispersal. Pineapple seeds irritate consumers -- this ensures that many different animals eat the plant. Some fruits act as a natural laxative to help with seed dispersal. Some seeds (e.g., oaks) will only sprout after a fire. This ensures that the soil is nutrient-rich.

TITLE: Fishing for Toothpicks (pond habitat 96, critters 124-127)

OBJECTIVES: Students will learn about camouflage.

METHOD: Game and discussion.

MATERIALS: Multicolored toothpicks, stopwatch.

TIME: 5 minutes.

• Camouflage helps many fish escape their predators.

Explain the many different coloration adaptations of fish.

(Mottled fish are disguised amid rocks and pebbles. Fish with stripes can hide in reeds. Fish with a light belly look like sunlight hitting the water to predators viewing the fish from below. Dark backs make fish look like the pond’s bottom to predators flying above.)

• Different colors are better disguised in different environments.

--Toss a handful of multicolored toothpicks into the air.

--Have the children race to find as many "fish" as they can in an allotted time.

--Ask students which colors they found the most/ least (e.g., students should find less green toothpicks because they will be camouflaged against the grass).

TITLE: "Show Me the Light" (the nature book 64)

OBJECTIVES: Students will use an underwater viewing table to see how diving beetles and water boatmen get oxygen.

METHOD: Experiment.

MATERIALS: Clear-bottomed water table, black posterboard, flashlight.

TIME: 5 minutes.

• Diving beetles and water boatmen need oxygen to breathe.

Explain how these aquatic invertebrates breathe (the insects swim to the surface of the water, collect oxygen, and store a bubble of water beneath their wings like a scuba tank).

Show the children how the insects swim to the surface.

• Beetles and water boatmen swim toward the light.

Ask the children where they think the insects will go if we cover the tank with black paper and shine a flashlight at the bottom (they will follow the light and swim to the bottom).

Test your hypothesis.

TITLE: Home Sweet Home

OBJECTIVES: Children will learn about the different pond habitats and view animal adaptations through a pond sampling exercise.

METHOD: Pond sampling.

MATERIALS: Canoe, seining net, buckets, dip nets, magnifying boxes, water table.

TIME: 45 minutes.

• First sample the open water.

Take the canoe to the middle of the pond.

Drag the seining net along the bottom of the pond and deposit fish in buckets.

Discuss the different fish and their adaptations with the students.

• Sample the water’s edge, surface film, and the bottom.

Children will use dip nets to sample pond life from each of the different habitats.

Students will collect the different organisms into large buckets.

• One of the teachers will supervise the children.

The supervising teacher will help the children with sampling and explain interesting adaptations.

Show the students how the dragonfly’s jaw unhinges. Have the children identify the water scorpion’s snorkel. Look for the beetle and boatman’s oxygen tank. Discuss coloration.

• One of the teachers will prepare the insects for observation.

Separate the animals into small magnifying boxes for observation.

Put some insects in the water table. Allow children to watch them swim around the tiny "pond."

TITLE: Moving Meals (hands-on nature 64)

OBJECTIVES: Students will see that frogs only eat moving prey.

METHOD: Game.

MATERIALS: None.

TIME: Varies.

• Frogs only eat moving prey. This is why you must feed a pet frog live food.

--The teacher is the frog and the students are insects.

--The frog stands on one end of the field. The insects join together about ten meters away.

--The frog turns his back to the students and chants "1-2-3, food for me" and turns to face the other children.

--Any ‘insects’ that are moving when the ‘frog’ turns around are eaten.

--Eaten insects move to the other side of the field to join the frog.

--Uneaten insects move three steps (one meter) closer to the frog.

--The game repeats itself as some prey are eaten and others step continually closer to the frog.

This unit focuses on properties of water and water quality. In order to instruct this lesson, teachers will need a general understanding of these concepts.

Water, or H₂O, is composed of hydrogen and oxygen. These atoms are so small that you cannot even observe them under a powerful microscope. Hydrogen and oxygen are both gases. When they combine in this ratio (two parts hydrogen to one part oxygen), they produce water. Each individual water molecule looks like a teddy-bear head -- the face is the oxygen atom and the ears are the two hydrogen atoms.

Temperature can affect water. Heat causes water molecules to move about rapidly. As the molecules collide with one another, individual particles are thrust into the air. These become water vapor. In contrast, cool temperatures cause water molecules to move about slowly, packing them together. In fact, when water freezes, the molecules bond together and form ice. Ice is less dense than water and floats on top of an unfrozen water body. Hot water, however, is less dense than cold (but unfrozen) water. This is why the top of a lake is generally warmer than the bottom. Because water has a high heat-holding capacity, it absorbs and releases heat more slowly than air does. As a consequence, temperature changes only gradually.

Water is a useful solvent. Thus, water can make many things disappear. This feature of water helps dissolve minerals in the soil to facilitate nutrient uptake by plants; gases, such as oxygen for fish to breathe; and chemicals in the air so that they are less harmful to humans. Water cannot dissolve oils, fats and waxes, however.

Plants transfer water through their stems via capillary action. The roots and stems of plants have narrow tubes. Water is drawn up through these tubes to feed the leaves of the plant. When the water reaches the leaves, it evaporates out of tiny holes. New water and dissolved nutrients enter the cycle again through the plant’s roots.

Water has a high surface tension. Because water molecules cling together so tightly, they form a skin at the surface that is not easily penetrated. In fact, some animals that are very light can literally walk on water!

Water and oil do not mix. In other words, oil is hydrophobic ("water hating"). This is why you have to shake salad dressing before you serve it. Otherwise, the oil will sit on top of the water. Detergent (and soap in general) has two ends, a hydrophobic end and a hydrophilic ("water loving") end. This is why we use soaps and detergents to remove stains: one end of the detergent molecule attaches to the oil, and the other attaches to the water. The detergent can pull the oil from our clothing! Experiments are being done to see if we can use detergents to clean up oil spills from our oceans!

There are many ways to evaluate water quality. These measures can be divided into physical, chemical and biological indicators.

Turbidity is an important physical indicator of water quality. When water is very cloudy (turbid) the sun cannot penetrate through the surface, thereby precluding plant growth. Because plants produce oxygen that pond life needs for respiration, water clarity is important for system health.

Turbid water generally has a great deal of suspended particulate matter. These materials can cover the gills of fish, which inhibits breathing. As suspended particles fall, they can cause a pond to fill in, becoming more shallow over time. (WOW 72)

Temperature is another physical indicator. Many pond organisms have stringent temperature requirements: insect larvae, many plants and some fish prefer temperatures above 55 degrees. Many factors influence water temperature: air temperature, overhanging vegetation, effluent from industry. Animals need oxygen for respiration. Cold water retains dissolved oxygen better than warm water does. Increased activity in the pond (with warmer waters) increases the demand for oxygen. Ironically, biological oxygen demand (B.O.D.) is highest precisely at the times when oxygen is most limited.

Dissolved oxygen (DO) levels vary throughout the year because they are temperature dependent. Thus, DO levels are reduced in the warmer summer months. Sometimes, an influx of nutrients (nitrates, NO₃, from fertilizer run-off or manure, for example) causes plants to grow at an enormous rate. This is called an algal bloom. The algae releases a lot of oxygen at first. As the algae continues to grow, it may block out sunlight, thereby preventing photosynthesis. The algae may grow to a point where it exceeds nutrient availability. This will cause a rapid die-off of the plants. As plants and animals die, they are decayed by bacteria that rely on oxygen for survival. Thus, decomposition requires large amounts of oxygen, and may actually lead to an oxygen debt in the water. Water with no DO is anoxic. No organisms can survive in anoxic waters. This excessive input of nutrients is called eutrophication. Although excessive nutrients are detrimental, nutrients are vital for plant growth. A healthy pond will have an intermediate level of nutrients. (golden guide pond life 12-13; pond water tour 38-61; WOW 71, 74)

Waste materials are another source of nutrients. Human and animal waste and plants produce ammonia (NH₃) when they decompose. Like nitrates (see above), moderate ammonia levels are important to fuel plant growth. Excessive levels of ammonia (e.g., from raw sewage or animal waste) can cause algal blooms. (pond water tour 61)

pH values are important chemical indicators of water quality. pH measures the percentage of hydrogen ions in the solution. Acidic water has a pH below 7. Acidic solutions have a higher concentration of hydrogen ions. Acid rain lowers pH levels. It is caused by the mixing of sulfur dioxide and nitrogen oxides from automobiles and factories with water from the atmosphere. Alkaline water has a pH between 8 and 14. A pH of 7 is neutral. Most organisms prefer water with a pH between 6.5 and 8.5. (WOW 68-69)

The different organisms in the water are a biological indicator of water quality. The biotic index uses aquatic animals to determine the health of a pond. Water quality is measured by classifying organisms according to their pollution tolerance. Some species can only live in clean water. The presence of these organisms is an indicator of good water quality. Biological Diversity is another indicator of water quality. Diverse systems have a wide range of plants and animals. Biological diversity is important because it allows for more complex food webs and ecosystem interactions. (aquatic WILD 35-39; education goes outdoors 173-178; habitats 35)

The activities that follow will better explain these concepts.—

• Aquatic WILD (Boulder, CO: Western Regional Environmental Education Council) 1987, pages 35-39.
• Hickman, Pamela M. Habitats: Making Homes for Animals and Plants (Reading, MA: Addison-Wesley Publishing Co.) 1993, page 35.
• Johns, Frank A., Liske, Kurt Allen, Evans, Amy L. Education Goes Outdoors (Menlo Park, CA: Addison-Wesley Publishing Co.) 1986, pages 173-178.
• Kohl, MaryAnn and Potter, Jean. Science Arts (Bellingham, WA: Bright Ring Publishing) 1993, page 98.
• Pond Water Tour: The Water Test Kit and Minicurriculum for Exploring Lakes, Streams and Ponds (USA: LaMotte Co.) 1994, pages 38-61.
• Reid, George K., Ph.D. Golden Guide Pond Life: A Guide to Common Plants and Animals of North American Ponds and Lakes (New York: Golden Press) 1987, pages 12-13.
• Seed, Deborah. Water Science (USA: Addison-Wesley Publishing Co.) 1992, pages 18, 20-21, 25, 28-29
• Slattery, Britt Eckhardt. WOW! The Wonders of Wetlands: An Educator’s Guide (St. Michaels, MD: Environmental Concern) 1991, pages 68-69, 71-74.

TITLE: What is Water?

OBJECTIVES: Children will learn what water is made of.

METHOD: Discussion.

MATERIALS: None.

TIME: 5 minutes.

• We use water for a lot of different things.

Ask the children to name some of the things they use water for.

Because water is all around us, it is important for us to understand what it’s made of and ‘how it works.’

• The chemical equation for water is H₂O.

Water is made of two elements: hydrogen and oxygen.

Hydrogen is symbolized with an ‘H,’ oxygen is symbolized with an ‘O.’

Water has more hydrogen than oxygen. In fact, there are twice as many hydrogen atoms as oxygen atoms in a water molecule (hence, H "2" O).

A molecule is the unit of all three atoms. Here, a molecule is like a teddy bear (draw a picture of a water molecule).

Atoms are even smaller than molecules. Each hydrogen or oxygen unit is an atom. You can’t even see these with a microscope!

• Water is cycled through our atmosphere

*Water falls as rain. It enters bodies of water directly or by run-off from roads and lawns. When water gets hot, the molecules collide with one another and "shoot" into the air! Thus, water molecules evaporate and become vapor. Water vapor collects in clouds and falls again as rain!

The rain we see outside may be from water that we used to water our lawns!

TITLE: (N)ice Trick (Water Science 18)

OBJECTIVE: Children will learn how animals can live in a frozen pond.

METHOD: Demonstration and discussion.

MATERIALS: A glass of water and an ice cube (for each group).

TIME: 5 minutes.

• Ice floats on water

Ask the children what will happen when you place an ice cube in a glass of water.

Show the children that the ice cube stays near the top of the water.

Ask the children if they’ve ever gone fishing in the winter.

Explain that only the top layer of the pond/ lake is frozen because ice forms from the top down.

Ice floats because it is less dense than water. This is because the water molecules expand and lock together to form ice crystals when they freeze. The empty space between the molecules makes it less dense (or lighter) than water.

• If water froze from the bottom up, many things would die in the winter.

Ask the children what would happen if ice didn’t float on top of water.

(The ice would sink to the bottom and freeze from the bottom up - killing all of the pond life in the process. The bottom of the pond would stay frozen in summer because the sun could not penetrate to the depths of the water.)

ACTIVITY THREE
TITLE: The Disappearing Trick (water science 20-21)

OBJECTIVE: Children will learn how water can be used as a solvent.

METHOD: Experiment and discussion.

MATERIALS: Two clear plastic glasses of water (per group). Sugar (for each group). Teaspoon (per group).

TIME: 5 minutes.

• Water is a useful solvent.

A solvent helps dissolve things. Water dissolves oxygen so that fish can breathe. Water dissolves nutrients so that plants can use them to grow. Water also dissolves the bad chemicals we put into it.

Ask the children what they think will happen when you add a teaspoon of sugar to a glass of water. (the sugar will disappear)

• Water cannot dissolve things without limit.

When water gets "full" it becomes saturated. Then, it cannot keep dissolving substances.

Ask the children what will happen when you add another teaspoon of sugar. And another? And another? (Eventually the sugar will settle to the bottom and the water will become cloudy)

Draw a parallel between the sugar and toxic chemicals: eventually, the water cannot absorb them either.

• The solvency of water is vital to life in the pond.

The plants and animals in a pond cannot "eat" oxygen and nutrients the way they are when they first enter the water. The water dissolves these substances so that they can be used to maintain life in the pond.

Fish breathe underwater by inhaling dissolved oxygen. Oxygen is a gas and the water dissolves it. Cold, fast-moving water holds more dissolved oxygen than warm water. That is why certain fish (e.g., salmon, trout) need cold, running water to survive.

Place a glass of cold water in a sunny spot. Tell the children to look at it in an hour or so. The children will see bubbles coming out of the water. This is the oxygen that is being released by the warm water.

Explain that bubbling water (e.g., water in a racing river) holds more oxygen because it is constantly being mixed with the air.

TITLE: Water Flows Upstream! (water science 28-29)

OBJECTIVE: Students will learn about capillary action.

METHOD: Experiment, arts-and-crafts project, and discussion

MATERIALS: Scissors, several coffee filters (cut into strips), water-soluble markers, several plastic cups filled with water (for each group).

TIME: 10 minutes.

• All plants need water to live.

Ask the children what a plant needs to survive. (water, air, sunlight, nutrients, and space)

Ask how a tall tree takes the water to its leaves. (through its roots)

Elaborate: Trees have "straws" inside of them. The straws literally "suck up" the water from the tree’s roots. These "straws" are really narrow tubes in the roots and stems of plants. The tubes take water and dissolved nutrients (remember water is a solvent) to the tree’s leaves. This is called capillary action.

• We can use capillary action to make cool art projects!

Color a large dot or design three centimeters from the bottom of the paper strips.

Fold the strip of paper over the edge of a plastic cup of water so that the end of the paper just touches the water.

Watch the water climb up the strips and spread the design.

Paper is made of tiny fibers with little tubes between them. Water molecules pull themselves up these tubes in the same way the molecules are pulled up the tubes of a plant.

TITLE: Water’s Tense Skin (water science 25)

OBJECTIVE: Children will learn about surface tension. They will understand how certain insects can walk on water.

METHOD: Experiments and discussion.

MATERIALS: A glass of water, a penny, an eyedropper, a pie tin, pepper (for each group). One bottle of liquid soap.
TIME: 10 minutes.

• Water has a high surface tension.

Water molecules cling together and are not easily broken. Because of this, some objects can lay on top of water without breaking through the surface.

Ask the children if they have ever seen a water strider.

• We can demonstrate how water molecules cling to one another with an experiment.

Ask the children how many drops of water they think can fit on a penny.

Use the eyedropper to slowly add water on top of a penny (first place the penny in the pie tin!). Have the children count the drops.

The droplets will keep adding up until they bulge over the top of the penny. At first, the water does not spill over because the water molecules are clinging together (via surface tension). Eventually, the weight of the added water will become so great that the water spills over the side of the penny.

• Some things can break the bond between water molecules. (mudpies to magnets 40)

Fill a pie tin with water. Sprinkle pepper on top of the water to illustrate how surface tension keeps the pepper afloat.

Pour a small amount of liquid soap down the side of the pan (teachers only!). The pepper will sink. The soap is hydrophilic (water loving). This means that the water molecules grab on to the soap instead of each other and the surface tension is broken.

• We can use this knowledge to understand how soap or detergent washes the grease stains

from our hands and clothes.

Oil is hydrophobic ("water hating"). This is why people say "water and oil don’t mix."

Ask the children what happens to salad dressing when they let it sit. (the oil and water separate)

Detergent has both a hydrophilic and a hydrophobic end. So, when detergent is added to water and oil, it grabs the oil with one end of the molecule and the water with the other. This enables the detergent to pull out the oil stain from our clothes!

• We see water tension in a pond.

A pond has four habitats (water’s edge, surface film, open water and bottom). Many insects (e.g., marsh treader, water strider) live on top of the water because they are so light they do not break through the water’s skin! These insects have long legs to help distribute their weight.

TITLE: Erupting Colors (science arts 98)

OBJECTIVE: Children will see how detergent can "grab" water and oil.

METHOD: Experiment.

MATERIALS: Cake pan, whole milk, food coloring (for each group). One bottle of liquid soap.

TIME: 7 minutes.

• Children will create an art experiment.

1. Pour milk into the cake pan until the bottom is covered.
1. Sprinkle 4-5 drops of food coloring on the milk.
1. Add a few drops of dishwashing detergent in the centers of the largest drops of coloring (teachers should add detergent!).
1. Watch the resulting eruption of colors.
1. If erupting slows down, try adding more food coloring and then more detergent. If the detergent will not work after awhile, begin again with new milk, coloring and detergent.

6. When experiment is complete, pan washes easily in warm water.

TITLE: Let’s Get Physical

OBJECTIVES: Children will learn about physical indicators of system health.

METHOD: Measurements.

MATERIALS: Thermometer, Secchi disc, canoe, measuring stick.

TIME: 10 minutes.

• Many organisms can only survive in a narrow range of temperatures.

Ask the children to guess the temperature of the water.

Ask the children why water temperature might change throughout the pond. (shade, water depth)

Ask the children what part of the pond they think will be warmest/ coldest.

Take temperature readings at various places in the pond (edge, open water).

• Turbid water can be harmful to pond life.

Ask the children why cloudy water might be bad for things that live in the pond.

(prevents sun penetration, clogs fish gills, obstructs vision, prevents predators from finding food, may fill in the pond.)

Ask the children what would make a pond cloudy. (erosion, run-off, algae, decaying materials)

Go out on the canoe and use the Secchi disc to measure the turbidity of the water.

• A pond is a shallow body of water with plants growing from shore-to-shore.

Ask the children how deep they think the water is.

Go out on the canoe and measure the water’s depth at various places.

TITLE: Cool Chemistry!

OBJECTIVES: Children will test chemical indicators (pH, dissolved oxygen, ammonia) of pond health.

METHOD: Experiments.

MATERIALS: Kitchen basters, various test kits from Pond Water Tour.

TIME: 10 minutes.

Split the class in half. Half of the students will test for dissolved oxygen and half will test for ammonia.

• Students will test for dissolved oxygen in the water.

Explain the importance of dissolved oxygen in the pond. Dissolved oxygen is vital for respiration. Cold water retains dissolved oxygen better than warm water. Dissolved oxygen levels are higher during the day when plants release oxygen during photosynthesis. High numbers are a sign of a "healthier" pond.

Students will test dissolved oxygen using the procedure and materials in Pond Water Tour (page 40).

After the test, students will share their findings with group two.

• Students will test for ammonia in the water.

Expain the implications of high ammonia in the water. High ammonia signifies a large amount of human and animal waste in the water. Low numbers are a sign of a "cleaner" pond.

Students will test ammonia levels using the procedure and materials in Pond Water Tour (page 39).

When students are done, they will share their results with group one.

• Students will test for pH.

Explain the significance of different pH levels. (lower numbers are acidic, higher numbers are alkaline. The pH scale runs from 1-14.)

Have each student test pH with litmus strips.

TITLE: Best Biology (education goes outdoors 173-178)

OBJECTIVES: Children will learn about biological diversity and indicator species.

METHOD: Pond sampling.

MATERIALS: Sample nets, buckets, several small aquariums, field guides.

TIME: 40 minutes.

• Some animals can only live in clean water.

Animals can be separated into different classes based on their tolerance to pollution.

These animals are indicators of system health.

Class 1 (pollution intolerant) animals include stoneflies, clams, caddisflies, aquatic beetles and mayfly nymphs.

Class 2 (moderately tolerant) animals include blackflies, crayfish, damselfly nymphs, dragonfly nymphs, fingernail clams and flatworms.

Class 3 (pollution tolerant) animals include leeches, midges, limpets, rat-tailed maggots and mosquito larva.

• A healthy system has a wide range of plants and animals.

A pond filled entirely with mayfly nymphs is not healthy, even though mayflies are Class 1 organisms. A diverse pond can support a more complex food web and a more complete ecosystem.

• Children will determine the pond’s biotic index.

The children will sample the pond for aquatic invertebrates using dip nets.

Students will empty their nets into larger buckets.

Periodically, the teacher will sort the buckets, placing each species in its own container.

Children will assess the health of the pond from the diversity and class of organisms caught.

The lessons in this unit focus on the daily, seasonal, and long-term changes in a pond ecosystem. The following concepts will provide a useful background for these lessons.

There are many subtle daily changes that occur in a pond. Temperature varies throughout the course of the day, dependent upon the level of the sun. During the daytime, the sun warms the water; at night, colder air cools the pond. Different animals take advantage of the changing amounts of sunlight in different ways. Nocturnal animals are active only at night, when the dark conceals them from predators. During the day, these creatures may stay hidden in the vegetation at the pond’s bottom. Diurnal organisms move about during the day; however, these animals might avoid particularly open areas. Crepuscular animals, like the fox, are active at both dusk and dawn, but not during the afternoon or night. Cold-blooded animals change their body temperature as air temperature varies. When it is cold, these animals are sluggish. In contrast, warm-blooded animals maintain a constant body temperature, despite external conditions. Plants require sunlight to complete photosynthesis. During photosynthesis, plants "breathe in" carbon dioxide and "breathe out" oxygen. Because photosynthesis can only occur during the daytime hours, oxygen and carbon dioxide levels vary with the time of day: oxygen levels are higher in the daytime when the plants are producing it.

There are many seasonal changes in a pond. Warm water is less dense (or lighter) than cold water. Water is most dense at 39.2 degrees Fahrenheit. This is why the top layer of a pond is warmer than the deeper layers during the summer. As the water cools in the fall, the temperature at the surface begins to match the temperature of the lower layers of water. As it cools (i.e., reaches 39.2 degrees), the dense surface water sinks to the bottom of the pond. The water continues to cool until it nears freezing. At this point, the density decreases (because ice is less dense than water). Now, the coldest water (the ice) is at the pond’s surface, with warmer layers farther down (the ice insulates these lower layers). As the spring sun melts the ice, the deep warm water "turns over" and circulates nutrients throughout the pond. These biannual mixings are called "overturns"; they help distribute nutrients throughout the water which helps support the varied pond life. (golden guide pond life 15-16; hands-on nature 111)

Animals adapt to changing temperatures in different ways. Some animals, such as birds, migrate to warmer climates. Other animals, especially reptiles and amphibians, hibernate during the winter. These animals may prepare for the winter by building up fat during the fall. During hibernation, breathing is slowed and uneven and temperatures are reduced. Very few mammals are true hibernators. Many animals, such as skunks, raccoons and chipmunks, are dormant during the winter months. These animals have a slightly higher body temperature than true hibernators and may awaken periodically to eat stored food or venture out during mild winter days. Other animals choose to "rough it out." These animals have special adaptations to endure the cold weather. For instance, some insects lose a great deal of the water in their bodies to prevent their cells from freezing during the winter. Their cellular fluid might become very sugary to prevent freezing. Some hide in or near plants, or in the mud at the pond’s bottom for insulation. (hands-on nature 88, 138)

Many insects correspond life-cycle changes to changing temperatures. Metamorphosis provides a way for insects to reduce their biological demands during the cold winter months. Metamorphosis is the transformation process from egg to mature adult. Metamorphosis gives insects flexibility to withstand changing temperatures and food supplies. In fact, some insects, such as the potato beetle larvae, delay hatching until potatoes are available. There are two kinds of insect metamorphosis: incomplete and complete.

Incomplete metamorphosis consists of three stages: egg, nymph and adult. The nymph looks like a wingless adult. The nymph molts as it grows, shedding its exterior skeleton and growing a new one. Often, because eggs hatch in water, the nymphs have gills to facilitate underwater breathing. Damselflies, grasshoppers, cicadas, dragonflies and mayflies undergo incomplete metamorphosis. The dragonfly may remain in the nymph stage for up to five years! For many insects, the nymph stage is longer than the adult. The mayfly, for example, lives as an adult for only two hours -- it does not even have a functioning mouth!

Complete metamorphosis consists of four stages: egg, larva, pupa and adult. Eighty-seven percent of insects undergo complete metamorphosis (e.g., moths, butterflies, bees, wasps, ants, beetles and flies). The egg hatches into a larva which does not resemble the adult. The larva lives in a different habitat, has chewing mouthparts and no compound eyes. When the larva has finished feeding and growing, it rests in a pupa stage (e.g., cocoon). During this time, the body is reorganized and adult organs slowly form. (hands-on nature 120-121, 137-140; ponds and streams 26-27)

Frogs, toads, salamanders and newts undergo amphibian metamorphosis. For example, when frog eggs hatch, tadpoles emerge. Tadpoles have rounded bodies, flattened tails and gills (for breathing in water). Tadpoles have a round mouth that is adapted for scraping algae. As the tadpole matures, it begins to grow hind legs. Next, front legs emerge. These grow in the place where the tadpole’s gills once were. Simultaneously, lungs replace the gills. The adult frog has eyes on top of its head and a wide gaping mouth to capture live prey. Finally, the tail is absorbed -- this helps "fuel" the metamorphosis process! (creepy crawlies and the scientific method 86-93; hands-on nature 61-66)

There are many long-term changes in a pond. These are called succession. In fact, a pond may fill in over time and become a meadow and eventually a forest! Succession is a natural process. First, plants and animals may die in the pond, adding to the decaying organic matter on the side of the pond. These materials have two effects. First, they begin to "fill in" the pond, making it more shallow. In addition, the decomposing organic material provides nutrients which facilitate increased plant growth. Over time, these plants die, thereby continuing the process. The pond will gradually fill in and become a marsh, swamp or bog. The wetland will eventually dry out as plants "suck up" water and add more matter to the area. Sun-loving trees invade, taking advantage of the wide-open habitat. In time, these trees will create a shaded canopy. Now, shade-loving trees grow in their place. In time, a forest replaces the former pond. (habitats 60-61)

Although succession is a natural process, humans can speed it up. When fertilizer enters water bodies (via run-off from our lawns after a rainstorm), we help more plants to grow -- and die; thereby, filling in the pond. When we feed ducks, we are doing the same thing! Increased food supply leads to increased waste. This enriches the nutrient base in the water. Humans can also slow down succession by dredging ponds, cutting down trees and mowing grass. —

• Hickman, Pamela M. Habitats: Making Homes for Animals and Plants (Reading, MA: Addison-Wesley Publishing Co.) 1993, pages 60-61.
• Kneidal, Sally Stenhouse. Creepy Crawlies and the Scientific Method (Colorado: Fulcrum Publishing) 1993, pages 86-93.
• Lingelbach, Jenepher. Hands-On Nature: Information and Activities for Exploring the Environment with Children (Woodstock, VT: Vermont Institute of Science) 1986, pages 61-66, 88, 111, 120-121, 137-140.
• Reid, George K, Ph.D. Pond Life: A Guide to Common Plants and Animals of North American Ponds and Lakes (New York: Golden Press) 1987, pages 15-16.
• Stidworthy, John. Ponds and Streams (Mahwah, NJ: Troll Associates) 1990, pages 26-27.

TITLE: Time to Take a Nap

OBJECTIVES: Children will understand the differences between nocturnal, diurnal, warm-blooded and cold-blooded animals.

METHOD: Interactive discussion.

MATERIALS: Live animals, preserved specimens and pictures.

TIME: 10 minutes.

• A pond appears to be a still body of water, but it is actually subject to daily, seasonal, and long-term changes.
• Fluctuations in temperature, light and oxygen have a profound effect on pond life.

During the daytime, sunlight warms the pond and plants capture the sun’s energy to make food. Photosynthesis reduces the carbon dioxide level in the pond and raises the amount of oxygen.

At night, plants use oxygen through respiration and release carbon dioxide. Thus, oxygen and carbon dioxide levels change throughout the day.

• Animals are nocturnal, diurnal or crepuscular.

Diurnal animals take advantage of higher daytime temperatures and oxygen levels by only being active during the day.

Nocturnal animals try to avoid predators by being active only at night.

Crepuscular animals are active at dusk and dawn.

Explain that animals are either warm-blooded or cold-blooded. The body temperature of cold-blooded animals varies directly with the temperature of the air and water. In contrast, warm-blooded animals can maintain a stable body temperature (therefore they can stay warm, despite cold temperatures).

Ask the children which type of animals, warm or cold-blooded, would they more likely expect to be active during the day (cold-blooded). Which would they expect to be active at night? (warm-blooded)

Explain that it’s actually not quite that simple -- all animals must be active when their prey are active.

Show the children pictures and live specimens of various animals: a painted turtle (cold-blooded, diurnal), bullfrog (cold-blooded, nocturnal and/or diurnal), garter snake (cold-blooded, diurnal), muskrat (warm-blooded, diurnal), bat (warm-blooded, nocturnal), raccoon (warm-blooded, nocturnal), duck (warm-blooded, diurnal), red-winged blackbird (warm-blooded, diurnal), great blue heron (warm-blooded, diurnal).

Ask the children to identify as many of the animals as they can.

Tell the children which of the specimens are warm-blooded and cold-blooded.

Ask the children if they can guess which specimens are diurnal or nocturnal.

TITLE: Water Volcano (the science book of water 14-15)

OBJECTIVE: Children will learn why the top of a pond is warmer than the bottom.

METHOD: Experiment and discussion.

MATERIALS: Clear tank or bowl, water (hot and cold), food coloring, small bottle with a cap.

TIME: 12 minutes.
PROCEDURE:

• Temperature, light and oxygen levels in a pond change throughout the year.

Explain fall and spring overturn (see background information).

Hot water is less dense than cold water. Things that are less dense float; those that are more dense sink. This is why the top of a pond is warmer than the bottom.

Ask the children if they have ever dove to the bottom of a lake and felt how much colder the bottom is than the top.

Ice is less dense than water, though (this is why ice cubes float). So, in the winter, the top layer is the coldest! As soon as the water warms to 39.2¡ F, the water "turns over" in the spring. This happens again in the fall when the water at the surface cools to 39.2¡ F and sinks. These fall and spring turnovers allow the water to mix better, thereby spreading the nutrients throughout.

• We can show how hot water floats on top of cold water.

Pour cold water into the tank until it is three-quarters full. Add several ice cubes.

Fill the bottle with hot tap water. Add a few drops of food coloring.

Screw the cap back on the small bottle and shake.

Place the bottle on the bottom of the tank.

Ask the children what will happen when the hot water is released into the tank.

Unscrew the cap. The hot water will rise to the surface (because it is lighter than the cold water).

As the water cools to 39.2¡ F, the colored water will sink and mix with the water in the tank.

• These changes affect animals.

Explain that even though days are shorter during the winter, and photosynthesis has shut down in plants, the oxygen level in the pond is high because cold water can hold more oxygen.

Ask the children how changing temperature, light and oxygen can affect pond life.

• Different animals adapt to these changes in different ways.

Explain migration. Ask the children to think of examples. Ask the children which animal at the front of the room migrates (south) for the winter? (the red-winged blackbird)

Explain hibernation. Very few mammals hibernate (little brown bat, woodchuck and jumping mouse), but most reptiles and amphibians do. Ask the children which of the animals at the front of the room hibernate? (all of the cold-blooded animals)

Explain dormancy. A bear is dormant over winter. Ask the children which of the animals at the front of the room is dormant during the winter? (the raccoon)

Ask the children to think of benefits of hibernation and dormancy.

TITLE: From Moth to Butterfly

OBJECTIVES: Students will learn about incomplete and complete metamorphosis.

METHOD: Interactive discussion.

MATERIALS: Preserved specimens, live animals, frog puzzle.

TIME: 15 minutes.

• Some animals adapt to changing conditions by changing themselves!

Explain metamorphosis.

Write the different stages on the board (complete: egg, larva, pupa, adult. incomplete: egg, nymph, adult).

Explain that life changes often correspond to the seasons. Animals want to "hide out" when the weather is cold and food supply is low.

Ask the children when an insect would most likely be in the pupa or nymph stage (fall or winter).

Ask the children when an insect would most likely be in the adult stage (spring or summer).

Show the children preserved specimens of the different stages. Pass them around the room.

Ask the children to think of the benefits of metamorphosis (the animal does not have to deal with diminished food supply or cold weather).

• Amphibians have a special kind of metamorphosis

Explain frog metamorphosis (egg, tadpole, adult).

Have the children look at live specimens to identify the differences between tadpoles and frogs.

Write a list of the differences on the board. Have the children think of the adaptive benefits of these changes (e.g., Why is a large mouth better on land? (to engulf prey) Why is a long tongue useful? (to catch live prey) Why do tadpoles have a small, circular mouth? (to scrape algae) Why are a frog’s back legs longer than its front legs? (to jump farther) Why are tadpoles found clustered together while frogs are found alone? (protection, more algae than flies)

Show the children plastic figures of each of the different stages. Have the children put the pieces in order (legs come before arms).

Show the children the frog puzzle. Have the students assemble the puzzle and take turns reading the different stages out loud.

TITLE: From Pond to Lawn

OBJECTIVES: Students will learn about succession.

METHOD: Interactive discussion.

MATERIALS: None.

TIME: 5 minutes.

• Explain that succession can change the state of the environment.

Seeds and leaves blow into the water and die.

Soil and leaves enters the water after heavy rainstorms.

Algae grows when there are a lot of nutrients in the water. When it dies, it may remain in the pond.

Slowly, the pond fills in from the bottom-up and from the edge-inward.

As plants absorb the water, the pond dries up and is converted to a wetland habitat.

• Explain that humans can slow-down or speed-up this process (succession).

Ask the children if mowing the grass alongside a pond slows-down or speeds-up succession. (slows it down)

Ask the children what would happen if we never mowed the grass. (the pond would fill in)

Ask the children to think of other ways humans slow-down (stocking animals) or speed-up (rerouting water, pollution, litter, sewage effluent) this process.

TITLE: Who’s Flying By?

OBJECTIVES: Children will learn about the field identification of birds. Students will become more aware of the pond and its inhabitants.

METHOD: Game.

MATERIALS: Dental floss. Needle. Cardboard birds.

TIME: 20 minutes.

• Explain that everyone can learn to be a birdwatcher.

When people identify birds, they look for a number of "tell-tale" characteristics. (unique coloration, plumage, beak shape, size)

Even if we don’t know the names of every bird, we can easily identify them if we learn to look for these signs.

• The children will try to identify some birds they might see near the pond.

Attach the dental floss to a low place downwind (e.g., bottom of a chair or fence post).

Hold the other end of the string while standing at a high place upwind (e.g., on top of a car).

"Fly" birds past the children by sending them down the string.

Ask the children to describe distinguishing characteristics and try to identify the birds.

At this point, the class will divide into two teams. One group will explore "The Changing Pond," the other will go on a sense scavenger hunt.

TITLE: Do You See What I See?

OBJECTIVES: Students will sharpen their senses and heighten their awareness of the pond and its inhabitants.

METHOD: Scavenger hunt.

MATERIALS: Assorted (stuffed and plastic) animals.

TIME: 20 minutes.

• Children will walk alongside the pond and try to find hidden objects.
• Children will look for signs of animal life.

TITLE: The Changing Pond

OBJECTIVES: Students will learn to identify clues about a changing environment and learn more about the pond’s inhabitants.

METHOD: Scavenger hunt.

MATERIALS: Dittos with list of clues.

TIME: 20 minutes.

• Students will walk alongside the pond and attempt to find clues about animal life and human-induced changes (e.g., "a place where pollution from our homes can enter the pond" a sewage drain). See attached list for clues.

Children will look for signs of animal life.

Allen, Maureen Murphy et al. Critters (USA: Aims Education Foundation) 1989.

Aquatic WILD (Boulder, CO: Western Regional Environmental Education Council) 1987.

Caduto, Michael J. Pond and Brook: A Guide to Nature in Freshwater Environments (USA: Hanover and London) 1985.

Dekkers, Midus. The Nature Book (New York: MacMillan Publishing Co.) 1988.

Esser, Liza. A Study of the Environmental Values of Current and Former Students in the Edgewood Park/ School Project: URI Working Paper #34 (New Haven, CT: URI, Yale School of Forestry and Environmental Studies) 1996.

Hancock, Judith M. Biology is Outdoors: A Comprehensive Resource for Studying School Environments (Portland, MN: J. Weston Walch, Publisher) 1991.

Hickman, Pamela M. Habitats: Making Homes for Animals and Plants (Reading, MA: Addison- Wesley Publishing Co.) 1993.

Honigfeld, Harriet. The Edgewood Park/ School Project: Innovation in Environmental Education URI Working Paper #13 (New Haven, CT: URI, Yale School of Forestry and Environmental Studies) 1994.

Imes, Rick. Practical Botanist (New York: Simon and Shuster Inc.) 1990.

Ingram, Mrill. Bottle Biology (Dubuque, Iowa: Kendall/ Hunt Publishing Co.) 1993.

James, Charles C. The Carnegie Academy for Science Education (Washington, D.C.: Carnegie Academy for Science Education) 1995.

Johns, Frank A., Liske, Kurt Allen, Evans, Amy L. Education Goes Outdoors (Menlo Park, CA: Addison-Wesley Publishing Co.) 1986.

Kneidal, Sally Stenhouse. Creepy Crawlies and the Scientific Method (Colorado: Fulcrum Publishing) 1993.

Kohl, MaryAnn and Potter, Jean. Science Arts (Bellingham, WA: Bright Ring Publishing) 1993.

LEAP (Learning About Plants) Grade 3 Curriculum (Ithaca, NY: Cornell Plantation) 1991, Unit I (available through Harvard University’s Arnold Arboretum; Jamaica Plain, MA).

LEAP (Learning About Plants) Grade 5 Curriculum (Ithaca, NY: Cornell Plantation) 1991, Unit I IV (available through Harvard University’s Arnold Arboretum; Jamaica Plain, MA).

Lingelbach, Jenepher. Hands-on Nature: Information and Activities for Exploring the Environment with Children (Woodstock, VT: Vermont Institute of Science) 1986.

Pond Water Tour: The Water Test Kit and Minicurriculum for Exploring Lakes, Streams and Ponds (USA: LaMotte Co.) 1994.

Project WILD (Boulder, CO: Western Regional Environmental Education Council) 1992.

Ranger Rick. NatureScope: Amazing Mammals Part I (Washington, D.C.: National Wildlife Federation) 1986.

Reid, George K., Ph.D. Golden Guide Pond Life (New York: Golden Press) 1987.

Seed, Deborah. Water Science (USA: Addison-Wesley Publishing Co.) 1992.

Sheehan and Waidner. EarthChild (Tulsa, OK: Council Oak Press) 1991.

Sisson, Edith A. Nature with Children of All Ages (New York: Prentice Hall Press) 1982.

Slattery, Britt Eckhardt. WOW! The Wonders of Wetlands: An Educator’s Guide (St. Michaels, MD: Environmental Concern) 1991.

Stidworthy, John. Ponds and Streams (Mahwah, NJ: Troll Associates) 1990.

URI. New Haven Urban Resources Initiative (New Haven, CT: URI) n.d. (Organizational brochure).

ADDRESS

February 3, 1997

Dear NAME,

As I explained in our telephone conversation, the Urban Resources Initiative (URI), in collaboration with the New Haven Parks Department and naturalist Susan Swensen, has engaged in an extensive environmental education program with the Edgewood Elementary School for the past six years. As a response to extensive community interest from the residents in the Beaver Pond neighborhoods and URI’s desire to expand its outreach in order to capture the educational opportunities of Beaver Ponds, we have decided to take the Edgewood model to other neighborhood elementary s