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Coral looks like a flower but can sting like a bee. Thousands of coral polyps live in a colony to form a coral reef. Reefs are like underwater versions of rain forests full of fantastic shapes and structures and life. The builders of the reefs, the coral polyps, have radial (rotational) symmetry. In this lesson, students will learn about radial symmetry and then have an opportunity to build symmetrical designs using pattern blocks. The lesson will take about an hour but the post-viewing symmetry activities can continue as long as interest is sustained. Students will learn about coral reefs while listening to a narrator read a New England Aquarium book, Dive to the Coral Reefs. Students will discover scuba diving as a way of exploring the coral reefs. They will get a chance to "pretend" dive with a partner, check dive equipment before diving, and then explore the wonderful underwater world of the reefs!
Reading Rainbow, #61: Dive to the Coral Reefs
Learning Objectives
After viewing various segments of the video and completing the hands-on activities, students will be able to:

Pre-Viewing Activities
What is a coral reef? After posing this question and allowing some time for discussion, explain that the class will be viewing Reading Rainbow program #61, Dive to the Coral Reefs. Since it is unlikely that most students at this age have actually gone snorkeling or scuba diving to see a reef, this video segment will give them a chance to role-play that situation.

Using pictures of a rain forest and a coral reef, compare and contrast how a coral reef and a rain forest are similar ecosystems where many living things grow in a very small area yet are very different because one is on land and the other is underwater. Many of the animals that live on a coral reef look like the plants of the rain forest.

Brainstorm a list of plants and animals that students think might seek food and shelter on a coral reef.

Assign dive partners for viewing. Make sure dive partners know to check with each other when questions are asked as only one answer will be accepted from each pair. This is done to encourage cooperative learning.

Hand-out the Diver's Logs attached to corrugated cardboard clipboards with large paper clips and pencils. Have students fill out the name, date, dive number, and dive buddy information. Directions for filling out the other sections will be given during pause points during the video. Tell students that from this point on they will be referred to as divers, not as students.
Focus Viewing
Explain to divers that they and their partners are marine scientists preparing to go on an underwater scavenger hunt for information that they will record in a Diver's Log. Working together, they will have to find the answers to a variety of questions about coral and diving.

To give divers a specific responsibility while watching the video, ask them to mentally check-off plants and animals they see on their dive trip that are on their list. Tell them to remember plants and animals that are not listed so they can be added later. Further, divers should be told to pay close attention to the shapes of the plants and animals of the coral reef, and in particular, the size and shape of a single coral polyp.

Viewing Activities
Host LeVar Burton and Park Ranger Mike White from the National Marine Sanctuary off the coast of Key Largo, Florida, will take us out to the reef. Divers will then watch as a narrator reads the book, Dive to the Coral Reefs. To give divers a specific responsibility while viewing this first segment say, "Listen for the host's description of where we are going for our dive trip today. I will stop the video to check to see if you and your partner know where we are going and why that location is a special one." Tell divers to make sure they watch for a forecast of visibility on the reef today.

START the video after the Reading Rainbow opening credits.

PAUSE when the host says, "There's a whole different world beneath the sea, and it's especially exciting here where there's a living coral reef." Ask divers if they know the location for their dive today and ask them to tell you why it is a special location. Check to see if any divers know the visibility on the reef today. Record visibility on the Diver's Log. Point to Key Largo, Florida, on a world map and note its relationship to the equator. Tell divers that we will now watch as a narrator reads the book, Dive to the Coral Reefs. To give divers a specific responsibility while viewing, direct their attention to the first Dive Orientation question that is in the Diver's Log: Where do coral reefs grow?

RESUME video as the host, LeVar Burton says, "Coral reefs only grow in warm, tropical waters so not everybody gets a chance to see them."

PAUSE when the book narrator says, "Coral reefs grow in tropical oceans all over the world." Ask divers to respond to the first Dive Orientation question, Where do coral reefs grow?, and to mark the correct answer in their log. Refer back to the dive location on the world map. Note that "tropical waters" refers to those areas on either side of the equator all around the world. Tell the divers that in the next segment, they will be trying to find the answer to the next Dive Orientation question: What is the approximate size and shape of one coral polyp?

RESUME video. The narrator will say, "To find out about these underwater coral communities the New England Aquarium sent a team of scientists and divers to explore a coral reef."

PAUSE immediately after the narrator says, "Each coral animal or polyp is about the size of a pencil eraser." The picture on the screen should be a close view of one coral polyp. Take this opportunity to walk up to the screen and lay on a clear piece of acetate with pie-shaped segments drawn on it. Students will see the circular or radial symmetry. Ask divers to respond to the second Dive Orientation question, What is the approximate size and shape of one coral polyp?, and to mark the correct answer in their log. The specific responsibility for viewing during the next segment is find the answer to the third and fourth Dive Orientation questions: How do corals build their skeletons? Do all corals build hard skeletons?

RESUME video as the narrator continues, "Some people are surprised to find out that corals are animals because many look more like plants."

PAUSE when the narrator says, "In ocean currents soft corals bend and sway like tree branches in a breeze." Have the divers respond to the third and fourth Dive Orientation questions, How do corals build their skeletons? Do all corals build hard skeletons? Have divers mark the answers in their logs. In the final segment of the book reading, the divers will find the answer to the last question: How does man contribute to the damage of coral reefs? Tell divers to be alert and that they will also see other plants and animals that make coral reefs their home. They can mentally check-off any plants or animals that are on the classroom list.

RESUME video. The narrator continues, "The reef is home to millions of plants and animals."

PAUSE the video at the end of the reading of the book where it says: THE END. Have the divers complete the answer to the last Dive Orientation question in the Diver's Log, How does man contribute to the damage of coral reefs? Tell them to check with their partner to make sure all their answers are the same. Tell divers that they are now going to see host LeVar Burton and Ranger White getting ready to explore a coral reef. To give the divers a specific responsibility for viewing, again they are to look for the answers to these Dive Preparation questions in their Diver's Log. What special equipment do divers need to wear? Why do scuba divers have to wear air tanks underwater but fish do not? What is the purpose of dive fins? Why do divers go down in pairs instead of alone?

RESUME video. LeVar Burton will be seen holding a copy of Dive to the Coral Reefs. He will say, "It's not everyday we get a chance to see a book come to life, but today we're going to because we're going to scuba dive the coral reefs."

PAUSE when LeVar says, "I'll check you out and then you check me out," and Mike says, "O.K." Have divers fill out the Dive Preparation questions in their log. Explain that when you resume play LeVar will be checking out Mike. Tell them to watch closely to see if they can remember all three check points in this next segment.

RESUME video. "Air on?" "Air's on." "OK, you have your weight belt on?" "Weight belt's on." "A little air in your vest?" (Mike pumps air into vest.) "Okey-doke." "All right, now let me check you." "Alrighty."

PAUSE when LeVar says, "Alrighty." Have the divers list each of the check points (air on/correct pressure, weight belt on, air in vest). Tell them that they can now check each other as you start and stop the video at each of the check-out points. They will WATCH; you will STOP; they will CHECK.

RESUME and PAUSE when Mike says, "Air on?" Dive partners check air.

RESUME and PAUSE when Mike says, "Check your air pressure." Dive partners check pressure.

RESUME and PAUSE when Mike says, "Weight belt on?" Dive partners check weight belt.

RESUME and PAUSE when Mike says, "A little air in the vest?" Dive partners check vest.

RESUME and STOP video when Mike says, "And check your regulator," and LeVar responds, "Here it is." Dive partners check regulators. Have divers report to Dive Headquarters (the teacher) with their Dive Logs. Dive Clearance will be okayed when the orientation and preparation questions are answered correctly. You can stamp each Diver's Log in the Dive Clearance section before continuing. And now, before entering the water, read aloud the Research Questions that all divers will be searching to answer while on their underwater scavenger hunt in this last part of the lesson: What do we call a group of fish that travel together? What kind of coral reef dweller makes sand? What kind of marine animal looks like elk horns or a human brain? When everyone is ready to dive, have divers record the actual time in the Dive Time-In section and then say, "Here we go!"

RESUME video as Ranger Mike says, "OK. I'll go first and wait for you in the water."

PAUSE just after the divers have gone past a school of grunt, the host says, "Hello, Grunt, don't mind us . . . just passing through." Ask students to address the first question, "What do we call a group of fish traveling together?" Say, "That right, it's a school of fish." Have all divers pretend to use their special underwater writing tools to record the answer to Research Question #1 before continuing. Remind students that in the next segment they will discover the reef dweller that makes sand IF they watch very, very closely. NOTE: Divers take a special plastic clipboard underwater and write on it with a regular pencil.

RESUME video. The divers will be touching the sea feathers and the narrator will say, "This cluster of sea feathers feels like a pile of goose feathers."

REWIND. After the video segment showing a red and white stoplight parrot fish, you will see a blue parrot fish. The narrator will say, "This blue parrot fish must have just finished supper. If you look closely you can see it releasing a stream of sand." At this point REWIND to the beginning of the blue parrot fish segment and tell students to focus closely on the blue parrot fish one more time.

PAUSE just after the blue parrot fish releases the sand and the narrator says, "Some scientists think parrot fish help make our beaches." Discuss Research Question #2, "What kind of coral reef dweller makes sand?" Say to the divers, "That's right again, it's a parrot fish." Have all divers record the answer and then continue the dive. Tell divers to focus on the general scenery in the next segment and try to see how a coral reef looks like a garden under the sea.

RESUME video. The blue parrot fish goes out of sight and there is no narration. You will see clusters of sea feathers and coral fans waving in the current. You do not see the divers.

PAUSE the video just after the narrator says, "Can you guess what it's called? Brain coral." Discuss Research Question #3, "What kind of marine animal can look like elk horns or a human brain?" Explain that elkhorn coral and brain coral are hard corals and have them record their answers in the Diver's Log. Ask divers if they think the coral reef looks like a garden under the sea. Alert divers that this next segment is the last one they will see today. If they listen carefully, they should hear the narrator tell them why fish swim together in schools.

RESUME video. There will be no narration when you resume, but when you see a school of fish the narrator will say, "When fish swim together it protects them from predators or bigger fish that might eat them."

STOP the video when you see the surface of the ocean.
Post-Viewing Activities
Have the student dive partners take off their pretend dive equipment and prepare to share what they observed as marine scientists. Record the actual time in the Dive Time-Out section and figure out your total dive time for this dive. Record it in the Total Time This Dive section.

Discuss with students the structure of a coral reef. Ask them to describe the corals they saw in the video. Make sure the student scientists understand the following points: Corals are actually thousands of individual coral polyps that join to make up one coral structure. Each little coral polyp has radial symmetry like a flower. A coral polyp can pull itself inside a hard shell it builds out of calcium carbonate. When a coral polyp dies, the hard shell remains and a new coral can build its home on top of the old one. In this way, the rock-like structures grow and grow, but only the outside layer of a coral structure is alive.

Tell students that coral are part of the Cnidaria family of animals. Sea anemones and jellyfish are also part of this family. These animals have radial symmetry like the spokes of a wheel. Explain that some other marine animals have bilateral symmetry. Use two apples to show what you mean by radial and bilateral symmetry. Cut an apple from stem to blossom end. You will have two halves, each half showing bilateral symmetry. Draw an imaginary line down the middle of one half. You again have two halves that are a mirror image of each other. Humans have bilateral symmetry. Have students face their dive partners and draw an imaginary line down the middle of their partner from forehead to feet. They will see two parts that are a mirror image of the other.

Tell students that Cnidaria (corals, jellyfish, and anemones) are different. They have radial symmetry. At this point, cut another apple in half by cutting horizontally across the middle of the apple. This time one half of the apple will have a star in the middle. Five-pointed stars have radial symmetry just like coral polyps and starfish. Use the example of a round pizza. If you cut a pizza into five pieces, each piece should look just alike. It has radial symmetry. Ask students to think of other objects in the environment that have radial symmetry. Write down any of their ideas and try to find pictures of these things. This list and the pictures can be used for an Extension Activity to the lesson. Tell students that they will now get a chance to build their own designs that have radial symmetry.

Students now get to "dive in" and try their hand at building symmetrical designs. Students are to work with their dive partner to create the designs. Each pair is given worksheet 2. They are to follow the directions so that they will end up with a circle with six folded pie-shaped sections. They need to press the paper out flat before building. Students can trace the fold lines with a black crayon. One child will use pattern blocks to create a design in one sector of the paper. Remind them to create the design so that no blocks cross the fold line. After they have completed the design in their space, the other partner tries to recreate the design in an adjoining sector. The first student again reproduces the same design in section 3 and the partner in section 4. The partners should now have a design with radial symmetry. If pattern blocks are not available, design figures can be copied, colored, and cut from worksheet #3 and glued on the paper. If a child cannot make block pictures with a partner, he or she should work alone to build a symmetrical design. Each time a block is placed in one sector, the child would place a matching one in the other sector or sectors until he or she has a completed design with radial symmetry.
Action Plan
Invite a scuba diver to bring his or her equipment into the classroom and discuss the training necessary to become a diver.

Contact people in your community who have to dive as part of their job and invite them in to tell about their occupation.

Contact your closest aquarium to see if they have outreach programs or go to visit if it is close enough.

Look in the Yellow Pages under Environmental, Conservation and Ecological Organizations to arrange speakers or tours of facilities stressing the importance of keeping our waters clean.

Math: Mirror Image Radial or Rotational Images: The child sets up a hinged mirror like a book to form a right angle, and a block design is constructed in the right angle. The child can then move the mirrors apart to form radially symmetric designs. The symmetric design can then be reproduced with blocks. NOTE: You will need single-sided and hinged mylar or pocket mirror or mylar can be purchased and glued to cardboard to make mirrors. You can hinge single mirrors with tape on the back sides only. Open the mirrors like a book to form a right angle.

Math: Recording Pattern Block Symmetry Patterns Pattern block templates can be made using large plastic coffee can lids (34.5 oz. size will allow each pattern shape to fit on one lid) . Trace the pattern block shapes on the lid and then use a carpet knife to cut-out the shapes. Each child will have his or her own template. These templates can then be used to trace the shapes of designs that are built. The traced shaped can be colored to match the color of the pattern blocks.

Math: Drawing Designs with Symmetry Cut symmetrical designs out of magazines and glue half of the design on the edge of an index card. Students place the index card on a piece of paper and try to draw the mirror image of the design on the paper. They can then take the card away and reproduce the mirror image of what they have just drawn. They should end up with a completed design.

Science: Make a Kaleidoscope You will need a paper towel tube cut to eight inches long, a clear plastic report cover, a ruler, crayon, dinner knife with a serrated edge, four-inch squares--one each of black construction paper, plastic wrap, and waxed paper, a sharp pencil, scissors, clear sticky tape, paper clips, sequins and beads, one rubber band, and gift wrapping paper. 1. Cut an 8-inch by 4-inch square of clear plastic from the report cover. Starting at the top, measure and mark-off lines 1 and 1/4 inches apart going horizontally across the plastic. 2. Fold the plastic along the lines to form a triangular tube. The narrow strip goes on the outside. 3. Slide the triangular tube inside the paper towel tube. The plastic will reflect light. 4. Using one end of the tube, trace the circular pattern on the black construction paper. Cut out the circle, poke a hole through the middle, and tape it over one end of the tube. This will be the viewing end of the kaleidoscope. 5. Place the square of plastic wrap over the other end of the tube. Place the paper clips, sequins, and beads on the plastic making a slight indentation. 6. Place the square of waxed paper over the bead, sequins, and paper clips and attach the two squares to the sides of the tube with a rubber band. You can trim the corners of the squares if you like. 7. Cover the tube with wrapping paper and enjoy the sight as hold your kaleidoscope to the light and look through.

Social Studies: Occupations Read the book, I Can Be An Oceanographer by Paul P. Sipiera, or a similar book about marine scientists to the children. Oceanographers study all aspects of the ocean. Sometimes they study the water, the waves, the tides, and the currents. Other oceanographers called marine biologists study plant and animal life in the ocean. Marine geologists study about the mountains, rocks, and minerals in the oceans.

Language Arts/Math: Mirror Writing Figure out which letters of the alphabet can be divided into similar halves--mirror images. Some letters can be divided horizontally, some vertically, and some diagonally. You can use letters or numbers written on cards with acetate letters or numbers traced to be the same size. Put a dot in the center of each number or letter to serve as the center of rotation. The child chooses a letter or number and its acetate counterpart. The child then rotates the acetate copy about its axis to see if the letter or number can be reproduced in a new position. Some will have vertical axis symmetry, some will have radial or rotational symmetry, some may have both kinds of symmetry, and others will not be symmetrical.

Master Teacher: Judy Handley

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