Third Grade - Science - Overview - February

Lessons 29 and 30 are intended to precede the performance assessment practice tasks. While knowledge of the content of these lessons is not necessary for success in the following performance assessment tasks, familiarity with marsh wildlife and the concept of a watershed will add dimension to the tasks and contribute to the confidence level of the students. Performance assessment tasks are best used in sequence.

Third Grade - Science - Lesson 29 - Marvelous Marshes of the Chesapeake
Watershed activity adapted from River Times, published by the Math and Science Center, Richmond, VA.

Objectives
Identify sources of salt water and fresh water that enter the Chesapeake Bay.
Build a model watershed and describe how runoff enters the Bay.

Materials
Map of Chesapeake Bay for transparency (attached)
Map of the Chesapeake Bay watershed for transparency (attached)
For each group of five students: baking pan or tray, newspaper, sheet of aluminum foil large enough to cover pan, package of dark-colored Kool-Aid, two small paper cups, pencil, water
Pictures of marshes from Suggested Books

Suggested Books
Bell, David Owen. Awesome Chesapeake: A Kid's Guide to the Bay. Centreville, MD: Tidewater Publishers, 1994. Not only is this one of the very few books on the Bay for children highlighting its wildlife, it is also extremely appealing and informative. The illustrations are wonderful and include cartoon asides that are very funny.
McLeish, Ewan. Wetlands. New York: Thomson Learning, 1996. Part of the Habitat series, this book looks at wetlands all over the world. The picture of a marsh in the Netherlands on page 11 could just as well be a marsh on the upper Bay.
NatureScope. Wading Into Wetlands. New York: McGraw-Hill, 1989. Contains numerous illustrations of marsh animals as well as activities, a wetlands adventure to read aloud, many copycat pages and arts and crafts projects such as making cattails.
Sayre, April Pulley. Wetland. New York: Twenty-First Century Books, 1996.
Suzuki, David. Looking at the Environment. New York: John Wiley, 1989.

Teacher Resource
Chase, Valerie. The Changing Chesapeake. Baltimore: National Aquarium in Baltimore and U.S. Fish and Wildlife, 1991. (booklet available free from National Aquarium) This 60-page booklet was designed for use by fifth graders and their families in conjunction with classroom study of the Bay. It contains information on the history of the Bay, its habitats and pollution problems as well as activities.
Horton, Tom. Bay Country. Baltimore: Johns Hopkins University Press, 1987. One of the most informative and beautifully written books about the Bay. Includes good black and white illustrations--one of a heron on page 136 and one of an osprey on page 158.
Reshetiloff, Kathryn, ed. Chesapeake Bay: Introduction to an Ecosystem. Washington, D.C.: U.S. Environmental Protection Agency, 1995. (booklet) There are pictures of geese, ducks and herons on page 3.

Procedure
Show the students the map of the Chesapeake Bay. Tell them that our Chesapeake Bay is the largest estuary in the U.S. Write estuary on the board. Tell the students that an estuary is a body of water where salt water mixes with fresh water. Ask: Looking at the map, where do you think the salt water in the Bay comes from? (Atlantic Ocean) Point out that the Bay is connected to the ocean; salt water flows into the Bay. Ask: Where do you think the fresh water in the Bay comes from? (rivers) Point out that there are many rivers flowing into the Bay. Have a student come up and point out some rivers that flow into the Bay. List them on the board. Ask: Do these sound like Native American names? Read some of the Native American names: Choptank, Nanticoke, Patapsco, Potomac. Remind the students that the people who lived in the Chesapeake Bay region named the rivers long before European explorers and settlers arrived.
Tell the students that there are 48 major rivers that feed the Bay with fresh water. Ask: Where does the water in the rivers come from? (Accept all answers.) Show the students the map of the Chesapeake Bay watershed. Point out that this view is a zoom out from the other map. Show them the outline of Maryland. Tell the students that this map shows the watershed for the Chesapeake Bay. Rain that falls on this area of land, and is not absorbed by plants or soil, flows downhill and toward the Bay. That is why it is called the Bay's watershed. Ask the students to imagine a trickle of melting snow on a mountain up in Pennsylvania. The trickle flows down the rocks and into a mountain stream. Then it races down a waterfall and into a bigger stream. It gurgles over rocks, down another waterfall and into a wide creek. The creek flows into a slower moving river. The river snakes through the countryside and then through a city before it widens again and joins the waters of the Chesapeake Bay.
Tell the students that water is not the only thing moving downhill. Streams and rivers carry what washes into them. While it is moving, the water is picking up tiny bits of rock and nutrients in soil and carrying them along. Remind the students about Big Bear Lake in Lesson 11. Ask: What else might rain be washing into streams and rivers? (trash, oil, gas, chemicals, sewage, cleaners) Point out that fertilizers and pesticides wash from farm fields into streams and rivers. Oil, gas, chemicals and trash are washed by the rain off streets and parking lots, into storm drains and then through pipes into streams and rivers that flow into the Bay. Tell them that what is washed from land into water is called runoff. Write this word on the board.
Divide the class into groups of five students and distribute materials and worksheet for making a model of a watershed. When the students are finished with the watershed model, ask: What did the sponges do at the edges of the Bay? (slowed down the water so it had to seep through the sponge before getting into the Bay) The sponges in the model were doing what marshes do at the edges of the Chesapeake Bay. Show the students pictures of marshes or wetlands from Suggested Books. Point out that marsh grasses and other marsh plants hold onto the soil with their roots in this very wet, sometimes flooded land. They slow the water down. Tell them that marshes or wetlands filter the water that runs into them and catch a lot of runoff before it reaches the Bay. They catch the nutrients in the runoff, too. The nutrients help the marsh plants to grow and to feed all kinds of wildlife that live in or visit the marshes. If available, show the students pictures of marsh wildlife from Suggested Books such as great blue heron, osprey, blue crab, muskrat, duck, etc. Tell them that next lesson they will be learning more about marsh animals and why the Bays' marshes are called "nurseries."

To Make A Model Watershed

Materials
baking pan or tray
newspaper
sheet of aluminum foil large enough to cover pan
teaspoon of dark-colored Kool-Aid
two small paper cups
pencil
water
strips cut from a sponge

Instructions
1. Make wadded-up newspaper balls and place them at one end of the tray for hills and mountains.
2.Cover the tray with the sheet of aluminum foil.
3. Gently press on the aluminum foil to cover the mountains and make valleys between the mountains.
4. Shape the foil to form a bay at the lower end of the tray.
5. Poke small holes in the bottom of a paper cup with a pencil point and place it inside another paper cup. Half fill the cup with water.
6. Holding the cup over the mountains, remove the outside cup and make it "rain."

Describe how the water moves in the model watershed.

__________________________________________________________________

7. Now sprinkle a small amount of Kool-Aid over the watershed. The Kool-Aid will represent soil nutrients and other runoff. Make it rain again.

Where did the runoff collect?

__________________________________________________________________

8. Put wet sponge strips at the edges of the "bay." Sprinkle with Kool-Aid again and make it rain.

What did the sponges do to the runoff? Did they stop it from getting into the Bay?

__________________________________________________________________

Third Grade - Science - Lesson 30 - Marvelous Marshes of the Chesapeake

Objectives
Describe what runoff does when it meets a marsh.
Identify some characteristics of blue crabs.
Describe some things that Chesapeake marshes provide.

Materials
Cattails (if available) or picture of marsh plants from Suggested Books
Crab shell and/or claw (if available) or picture/representation of crab
Life cycle of the blue crab for transparency (attached)

Suggested Books
Cummings, Priscilla. The Chadwick series. Centreville, MD: Tidewater Publishers. Stories about a crab of the Chesapeake Bay with whimsical illustrations.
NatureScope. Wading Into Wetlands. New York: McGraw-Hill, 1989. There is a picture of a blue crab that can be reproduced on page 32 and a picture of a cattail plant on page 57.

Teacher Resource
Warner, William. Beautiful Swimmers: Watermen, Crabs and the Chesapeake Bay. Boston: Little, Brown, 1976. This Pulitzer Prize-winning book is truly a treat. Not only will the reader learn much about crabs and crabbers, but he or she will gain a new respect for the beauty and elegance of the Bay's creatures. Pages 104 and 105 include great illustrations of crabs in the various stages of their life cycles. On pages 112 and 113 there are illustrations of a crab's courting dance.

Procedure
Remind the students that in making model watersheds they learned something about marshes around the shallow edges of the Chesapeake Bay and runoff. Ask: What is runoff? (water that flows over land and into streams and rivers) What can runoff carry with it? (soil, nutrients, gas, oil, trash, fertilizers, pesticides and other chemicals, cleaners) What happens when runoff meets a marsh? (The marsh plants slow down the flow of the water. They filter the runoff before it reaches the Bay.) Remind the students that runoff brings nutrients from soil into the marsh. The nutrients settle in the water and mud of the marsh and feed the marsh plants and grasses. They also feed tiny water plants. The plants above water and below make good hiding places for animals in the marsh and also provide food.
Point out that the plants, grasses and tiny water plants are the beginnings of many food chains in the marsh. Ask: What is a food chain? Remind the students that plants make energy, animals get energy by eating plants or by eating animals that eat plants. Write this example of a marsh food chain on the board: tiny water plants ÷ shrimp ÷ small fish. Point out that the shrimp eats the tiny water plants and captures their energy. Then the small fish gets energy by eating the shrimp.
Remind the students that last lesson you called the marshes "nurseries." Ask: What is a nursery? (a place for babies) Tell the students that the marsh is a great habitat for baby animals. In spring, birds nest in the marsh. The tall marsh grass makes good camouflage for nests where the young will be safe. Show the students a cattail or picture of one. Tell them that this cattail is one of the plants that grows in marshy areas. Ask: Why do you think it is called a cattail? (fuzzy end looks and feels a little like a cat's tail) Tell the students that birds use the cattail's leaves to build their nests. They also eat the seeds in the cattail's fuzzy seed pod. Other animals such as muskrats eat the rootstalks of the cattail where the plant's food is stored.
Tell the students that in shallow waters around the roots of water plants, baby fish, crabs and shrimp find hiding places, too. Bigger fish that might eat them cannot find them as well in the plant-crowded marsh as they might in open water. Then when the babies get big enough, they move out into deeper Bay waters.
Show the students the transparency of the crab's life cycle but cover the word crab and the final stage. Tell the students that the transparency shows the stages in the life cycle of an animal that lives in the Bay. Ask the students if they can identify this baby animal. (Accept all answers.) Uncover the title and the final stage. Tell the students that these are life stages of the blue crab. Ask: Is the crab a vertebrate or an invertebrate? (invertebrate because it has no backbone) Point out that the crab's first stage after hatching is called a zoea or larva. Ask: What other animals go through a larval stage? (insects) Tell the students that crabs in their larval stage are so tiny that they are invisible to the eye. They are about 1/100th of an inch long--smaller than the point of a pin. Tell them that blue crabs actually go through seven larva stages. When changing from one stage to another, they shed their very tiny shells and grow new ones. This is called molting.The next big change in the crab is to a stage called a megalops. Ask: Does a megalops look like an adult crab? What about it looks different? (narrower body, a tail, no swimmers on back legs) Tell them that when the megalops molts and changes into a crab, it has grown to the size of a small freckle. It must grow and molt many times before it is big enough to crawl or swim into deeper water. Then it must continue to molt every time it grows a little bigger. It takes almost two years of molting and growing before a crab is an adult.
Point out that while the crabs are in the early stages of their life cycles, the marsh is the safest place to be. Ask: Why is it safer in the marsh for the baby crabs than in the open water of the Bay? (There are places to hide from predators in the marsh.) Show the students the crab shell, claw or pictures of blue crabs. Point out the sharp "teeth" on the claws. Ask: What do you think a crab uses its claws for? (defense, tearing food, eating) Tell the students that crabs eat dead fish, clams, oysters and plants. Ask: Has anyone ever heard of a soft-shelled crab? (Accept all answers.) Tell the students that soft-shelled crab sandwiches are on the menus at many restaurants in Maryland. Ask: Why do you think the crab's shell is soft? (It has just molted and the new one has not hardened yet.)
Returning to marshes, review with the students the characteristics of marshes at the edges of the Chesapeake Bay. Write Marshes are... on the board and ask students to provide descriptions or what marshes are like and what they do. Remind the students that marshes act as filters to trap runoff before it reaches the Bay waters. They provide habitat for wildlife. They are nurseries for baby animals. They provide hiding places.

Possible Field Trips
Black Marsh (a Chesapeake Bay marsh) is located in North Point State Park near Fort Howard. There is a visitor's center with some exhibits, but the main attraction is the marsh. Visitors to the state park walk along trails where trolley cars once ran from Baltimore to Bay Shore Park, an amusement park that closed in 1947. Park rangers are available to lead school groups. Call the Maryland Department of Natural Resources for more information and directions.
A trip to the top of World Trade Center can reveal how the harbor is connected to the
Patapsco River.
The Maryland Science Center includes extensive exhibits that focus on the Chesapeake Bay watershed. There is also, of course, the giant blue crab!
Lexington Market is a good place to see crabs, oysters and other seafood from the Bay.

Bibliography

Read Alouds
Cummings, Priscilla. The Chadwick series. Centreville, MD: Tidewater Publishers.
Bell, David Owen. Awesome Chesapeake: A Kid's Guide to the Bay. Centreville, MD: Tidewater Publishers, 1994. (0-970-33457-3)

Student Reference
McLeish, Ewan. Wetlands. New York: Thomson Learning, 1996. (1-568-47319-2)
Sayre, April Pulley. Wetland. New York: Twenty-First Century Books, 1996. (0-805-04086-2)
Suzuki, David. Looking at the Environment. New York: John Wiley, 1989. (0-471-54749-2)

Teacher Reference
Chase, Valerie. The Changing Chesapeake. Baltimore: National Aquarium in Baltimore and U.S. Fish and Wildlife, 1991.
Horton, Tom. Bay Country. Baltimore: Johns Hopkins University Press, 1987. (0-801-84875-X)
NatureScope. Wading Into Wetlands. New York: McGraw-Hill, 1989. (0-070-46507-X)
Reshetiloff, Kathryn, ed. Chesapeake Bay: Introduction to an Ecosystem. Washington, D.C.: U.S. Environmental Protection Agency, 1995. (booklet)
Warner, William. Beautiful Swimmers: Watermen, Crabs and the Chesapeake Bay. Boston: Little, Brown, 1976. (0-140-04405-1)