Backyard Rocks: Sorting Out Descriptive Details SEASONS: SUBJECTS: EXT. SUBJECT: TK MATERIALS For each student: small plastic bag for rocks, note card. For each group of students: sedimentary, metamorphic, and igneous rock cards. PREP TIME: LESSON TIME: + OR X 4 Description Students isolate descriptive details of rocks found outside to identify and then classify their rock samples. Preparation for this lesson involves finding an outdoor location for a rock collection walk, gathering rock collection bags, making copies of the rock cards, and reviewing the Backyard Rocks Rubric. Students first go outside to collect rock samples and then, back in class, they choose one rock to explore in detail. To practice using descriptive words, students write notes about the rock on a note card. These notes are then distributed among the class so students can match the description with the appropriate rock sample. After experiencing the importance of identifying details, students then use information about the three types of rocks igneous, sedimentary, and metamorphic to classifying their rocks. In small groups students discuss and debate their reasons for their classifications and then present their conclusions to the class. As a concluding activity, students use their investigations and rock descriptions to write about their rock samples. For a hands-on simulation of the rock cycle, the extension activity provides students with the opportunity to take a crayon through the rock cycle while identifying key characteristics of the three types of rocks. 39
Objectives Investigate and classify local rock specimens. Learn characteristics of sedimentary, metamorphic, and igneous rocks. Describe common rocks using specific language. Background Information Rocks and minerals are important natural resources. We use them for building countertops and school foundations. There are minerals found in our food. Berkshire rocks and minerals may turn up in your chewing gum (Adams calcium carbonate is that white powder on the gum that prevents it from sticking to the paper wrapper); the nation s capitol building and Empire State Building (Lee marble); and Harvard Medical School (Adams limestone). Minerals from one site in Adams are used worldwide in paint, paper, and plastic manufacture. 40
Remember, rocks contain minerals, but minerals do not contain rocks. Minerals have a definite chemical composition. Rocks have gone through a process of breaking down and building up many types of minerals; they are the result of a dynamic process called the rock cycle. The three main types of rocks igneous, metamorphic, and sedimentary represent different stages in the rock cycle. Igneous (from the Greek word igne, which means fire ) rocks form from the cooling and hardening (solidification) of hot molten rock inside the earth (magma) or outside the earth s crust (lava). Sedimentary rocks form from the slow accumulation of dust and rock particles into layers of sediment, which pile up and compress at the bottom of lakes, rivers, and the ocean. Erosion and weathering are the main forces that create these particles. Metamorphic (from the Greek word morphos, which means change ) rocks form from chemical reactions and/or the heat and pressure created inside the earth, which cause igneous and sedimentary rocks to undergo change. Igneous Rock Magma cooling melting heat & pressure weathering & erosion Sediment melting weathering & erosion weathering & erosion compaction & cementation Metamorphic Rock heat & pressure Sedimentary Rock 41
The bedrock and surface rocks in Berkshire County were formed by several collisions of continents and pieces of continents from 1 billion to 250 million years ago, and by the slow thrust and retreat of glaciers 1.6 million to 16,000 years ago. Even though all three types of rocks can be found in the Berkshires, sedimentary and metamorphic rocks are the most common. The plate tectonics and continental collisions caused the mud, seashells, and sand that make up sedimentary rocks to be pushed inland where some were heated and compressed into metamorphic rock. Fossils, which are safe in sedimentary rock, are nowhere to be found, except 10 to 15 miles west in New York state, where the ocean floor was not banged around as much. The Berkshire Hills contain large quantities of the sedimentary rocks limestone and shale, and their metamorphic counterparts marble and schist. Identifying the different types of rocks can be accomplished by following the prime rule of geology: when in doubt, look for another rock! The Online Resources also have user-friendly rock identification keys. In general, sedimentary rocks can have a rough or sandy surface and be made of large particles and layers. Metamorphic rocks also display layers but in a more refined manner, in bands of color and sediments with small crystals. They have a smooth surface, are hard, and resistant to wear. Igneous rocks are also hard, smoother, and glassy, but their composition is usually made up of larger crystals, the result of lesser pressure than metamorphic rocks. For instance, of the three rocks found in Berkshire County, limestone (sedimentary) has few crystals, dolomite (sedimentary) has large crystals, and marble (metamorphic) has small crystals. 42
Procedure + or X 4 1. Take students on a rock-collecting walk around the schoolyard (see Tips for Teaching Outdoors, p. 1). Ask each student to look for a variety of rocks and to place three samples in a plastic bag. 2. Back in the classroom, each student can choose one rock sample from the three collected and write and/or draw the characteristics of that rock on a note card. Is it smooth? Rough? Sandy? Lined? What is the size? Color? Is it heavy? Light? Brainstorm adjectives that students can use to describe their rocks. Students names should go on the back of the note card. 3. Students can place their rocks in line along the floor or ground. Collect the note cards and pass them out to different students. TIPS AND TRICKS Short on time? The lesson can be broken up into parts: (1) collecting rocks, (2) describing and matching rock samples, (3) classifying rocks, and (4) writing descriptive paragraphs about the rocks. Younger students can dictate rock descriptions and use a word bank of descriptive words. 4. Each student can use the clues from the note card to try to find the matching sample. After choosing the sample that best fits the description, they can explain how they found their rock and return the rock to the person who wrote the description. 5. Introduce the concept of classification. How can students be grouped according to shirt color? Eye color? Explain how scientists group similar objects to help identify the objects. 6. Break students into small groups. Pass out sedimentary, metamorphic, and igneous rock cards to each group. Explain that each card has an example of a type of rock that scientists use to help with rock identification. Using the cards, allow students to classify their collected samples according to the three types. 7. Discuss the characteristics of the three types of rock and how the groups classified the rocks they collected. 8. As a concluding activity, students can write a descriptive paragraph about each rock. If necessary, students can refer back to the descriptive note cards. 9. If there are not a large number of rocks to be found in the schoolyard, be sure to return the rocks outdoors at the end of the lesson for the next class to use. 43
LIVING LANDSCAPES Rocks Sedimentary Rocks feel rough contain small rocks or sand crumble or break apart Metamorphic Rocks smoother than sedimentary rocks contain lines or waves hard to break Igneous Rocks very smooth (smoother than sedimentary and metamorphic rocks) contain speckles really hard to break 44
Assessment BACKYARD ROCKS RUBRIC 4 3 2 1 Descriptive Details Describes rock samples with many rich and relevant adjectives. Describes rock samples with some rich and relevant adjectives. Describes rock samples with a few rich and relevant adjectives. Does not describe rock samples with rich and relevant adjectives. Group Work Listens actively, stays on topic, considers the ideas of others, respects others, and takes turns. Most of the time listens actively, stays on topic, considers the ideas of others, respects others, and takes turns. At least some of the time listens actively, stays on topic, considers the ideas of others, respects others, and takes turns. Has difficulty listening, staying on topic, considering the ideas of others, respecting others, and taking turns. Classification Groups rock samples according to characteristics of sedimentary, metamorphic, and igneous rocks. Groups most rock samples according to characteristics of sedimentary, metamorphic, and igneous rocks. Groups a few rock samples according to characteristics of sedimentary, metamorphic, and igneous rocks. Doesn t group rock samples according to characteristics of sedimentary, metamorphic, and igneous rocks. Science Extension: Rock Cycle Simulation Give each student a colored crayon (a variety of colors with the paper peeled off) and explain that the crayon represents an igneous rock that has been cooled from under the earth s crust. Ask students to examine their igneous rock crayons and describe characteristics or properties. Key observations include small holes produced from air bubbles upon cooling, one uniform substance, and smooth (almost glassy) luster. Next, students weather the rocks using craft sticks to break the crayons into small bits or shavings. Students place the crayon sediments into a plastic bag (one bag for each group) and take turns adding pressure by pressing the bag between their hands. After the students get the crayon sediments to stick together, they take out the newly formed sedimentary rock crayon and describe this rock type. Key observations include visible pieces of rock fragments/particles, possible stratification (visible layering), not as hard as the igneous rock crayon. Next, students add heat to their rock crayons. In their groups, students place sediments and sedimentary rock crayons into a foil baking cup, attach a clothespin to use as a handle, and hold the cup over the flame of a candle until the pieces melt together. For safety, place the candle in the middle of a pie pan filled with water. (Note: Remove the cups from the heat as soon as the crayons melt!) Let the melted crayon cool and solidify. 45
After students remove these metamorphic rock crayons from the cups, the teacher slices up the rock-crayon pieces with a razor blade or scissors so students can examine the inside. Key observations include no individual particles seen, but rocks contain many different substances; colors may be swirled together rather than layered or chunked; hardness is increased (compared to the sedimentary rock). SERVICE LEARNING BACKYARD ROCKS: ROCK ON! Make a board game about the rock cycle using different rocks as the playing pieces and clue cards based on information learned. Play the game with students from other classes and donate the game to the school library. Resources Hiscock, Bruce. The Big Rock. New York: Atheneum, 1988. Traces the origins of a granite rock located near the Adirondacks and describes how it reveals information about the history of the earth. Hooper, Meredith. The Pebble in My Pocket. New York: Viking, 1996. After a girl finds a pebble and wonders about its origins, the story traces the pebble s history as the earth undergoes vast changes. Thorson, Kristen, and Thorson, Robert. Stone Wall Secrets. Gardner, ME: Tilbury House, 1998. As a grandfather and grandson walk along the stone walls surrounding a New England farm, the grandfather shares stories about the stones geological history and his own memories. 46
Online Connections Visit the Berkshire Museum s Living Landscapes website at www.berkshiremuseum.org/programs/educators.html for the following online activities or resources: Rock identification keys Rocks and minerals pictures and further information Extensive rock and minerals projects Sources of rock or mineral samples MASSACHUSETTS FRAMEWORKS Science: Earth and Space Science: Earth s Materials Pre K-2 1. Recognize that water, rocks, soil and living organisms are found on the earth s surface. Science: Earth and Space Science: Rocks and Their Properties Grades 3-5 *For Lesson and Extension 3. Identify the three categories of rock based on how they are formed, and explain the natural and physical processes that create these rocks. Science: Physical Sciences: Observable Properties of Objects Pre K-2 1. Sort objects by observable properties such as size, shape, color, weight, and texture. Science: Physical Sciences: Properties of Objects and Materials Grades 3-5 1. Differentiate between properties of objects and properties of materials. Science: Technology/Engineering: Materials and Tools ELA: Language: Standard 1 Discussion ELA: Language: Standard 2 Questioning, Listening, and Contributing ELA: Language: Standard 4 Vocabulary and Concept Development Pre K-2 Pre K-4 Grades 5-6 Pre K-2 Grades 3-4 Pre K-K Grades 1-2 Grades 3-4 Grades 5-6 1. Identify and describe characteristics of natural materials and human-made materials. 1. Follow agreed-on rules for discussion. 3. Apply understanding of agreed-on rules and individual roles in order to make decisions. 1. Contribute knowledge to class discussion in order to develop a topic for a class project. 2. Contribute knowledge to class discussion in order to develop ideas for a class project and generate interview questions to be used as part of the project. 2. Describe common objects and events in general and specific language. 3. Identify and sort common words into conceptual categories (opposites, living things). 13. Determine the meaning of unknown words using their context. 17. Determine the meaning of unfamiliar words using context clues (definition, example). The lesson also addresses the Massachusetts Science and Technology Curriculum Framework s Science Skills of Inquiry. 47