Geology, Part 2: What Is the Mystery Rock?

Geology, Part 2: What Is the Mystery Rock? You and your partner will be given 14 rocks to identify. Using the chart provided, follow the steps by observing your rocks closely and using the tools available. Identify each of the rocks you have. Once you have identified the 14 rocks, select an unidentified rock from the box. Using what you learned from the chart identification, identify the mystery rock. Draw a picture of the mystery rock, record your observations and the properties of the rock that you found, and then identify your rock. Be sure to support your identification with evidence. We will then share and compare our identifications with the whole class. 1 of 13

Suggested Grade Span 3 5 Task You and your partner will be given 14 rocks to identify. Using the chart provided, follow the steps by observing your rocks closely and using the tools available. Identify each of the rocks you have. Once you have identified the 14 rocks, select an unidentified rock from the box. Using what you learned from the chart identification, identify the mystery rock. Draw a picture of the mystery rock, record your observations and the properties of the rock that you found, and then identify your rock. Be sure to support your identification with evidence. We will then share and compare our identifications with the whole class. Big Ideas and Unifying Concepts Cause and effect Patterns Systems Physical Science Concept Properties of matter Earth and Space Science Concept Earth structure and system Design Technology Concept Use of tools Mathematics Concepts Data collection, organization and analysis Diagrams Measurement 2 of 13

Time Required for the Task Approximately one 45- to 60-minute session. Context This task was given to students during a unit on geology. Before this task, students had investigated individual rocks using different tools and tests to find out what kind of rocks they were. (See "Geology, Part 1: Can You Categorize Different Types of Rocks?") Students had also begun to learn about the three types of rocks (igneous, sedimentary, and metamorphic) as well as the difference between rocks and minerals. Students had sorted and categorized a group of unknown rocks by observation and tested properties. Students at this point were familiar with tests that can be performed to determine certain properties (scratching the surface with a nail for hardness testing, testing for calcite and looking for minerals) and how to use tools to make observations. The flowchart enables the students to apply what they have learned so far to identify a number of different types of rocks and then to identify a mystery rock. What the Task Accomplishes This task serves a number of purposes. First, it assesses how effectively students can identify rocks by observing characteristics and testing for properties. Second, it assesses their ability to provide detailed observations of these characteristics and properties and then support their identifications with evidence from their observations and testing. Finally, it assesses students' use of tools and application of prior knowledge tests to determine the physical properties of these rocks. How the Student Will Investigate Students worked in groups of two during this activity. They were given a set of 14 purchased rocks (see Suggested Materials list) and the flowchart to aid in identification. Also available from previous investigations were tools and materials that students could use for observing and testing their rocks. Students then used the chart to identify each of the 14 rocks. Once they had correctly identified each of the rocks, they chose a mystery rock from a box. The mystery rocks were an assorted collection of the rocks from the chart, but of different sizes and shapes. Students then used the chart, tools and tests to determine what the mystery rock was. Once these were identified, students recorded their work and shared the identifications with the others in the class to verify whether they were correct. 3 of 13

Interdisciplinary Links and Extensions Science For other tasks in geology, see this CD. Language Arts From this activity, students added new information about these 14 rocks to their own field guides created earlier in the unit (See "Geology, Part 1: Can You Categorize Different Types of Rocks?"). These field guides were used in several field studies that the students did at local outdoor areas. Students also researched published field guides to learn more about each of these rocks. A number of fiction and nonfiction books were integrated as well. (For a list of geology-related books, see Part 1 of this task.) Students could write their own informational texts about how their mystery rocks were formed. Social Studies This unit is often done in connection with Vermont history, as well as the history of the earth. Invite your state geologist to visit the classroom to share this history with students. Students could create state, country or continent maps that show different rock types and geological activity. Teaching Tips and Guiding Questions It is important before doing this assessment activity that students have previous experience with the tools and tests to help them learn about rocks. It is also helpful to review with them the properties and characteristics to look for when categorizing their rocks. These include minerals (color and number), layers (number and type), texture, hardness. The rocks can also be tested for calcite content. When splitting rocks open, always wear safety goggles and wrap rocks in newspaper to prevent small pieces from flying. The chart includes a number of questions that the students ask as they look at each rock. Some rocks may be difficult to identify without observing them very closely. Marble fizzes with vinegar, but students will need a magnifying glass to see the bubbles. Students can also scratch the surface of a rock with a nail and then pour vinegar on it. This makes the bubbles more apparent. Color can be difficult as well. A rock may be grayish in color but be considered a light color on the chart. Dark means very dark or black; any other color is considered light. Also, some light-colored rocks may have dark minerals in them. Encourage students to observe carefully and to try things a couple of times to make sure that the rock is what they think it is. Possible guiding questions to ask as students investigate: What do you observe about these rocks? How are they alike? How are they different? How does your rock feel when you touch it? What does your rock look like? Are there layers in it? How are the layers arranged? Are there different colors in the layers? How can you tell if there are layers? 4 of 13

Can you describe the colors? the texture? How might this rock have been formed? What might have made the rock smooth? rough? Are there crystals in the rock? How do you know? What else do you notice about the rock? How can you tell if minerals are present? How many minerals do you see? Can you identify these minerals? Does the rock react to vinegar? Does a magnifying glass help you see any bubbles? What do you notice under the microscope? (Students use small chips taken from their rocks to look for minerals.) What happens when you scratch your rock with a nail? Does that mean it is hard or soft? What would happen if you used a nail to scratch the rock before testing with vinegar? How did the chart help you to categorize these rocks? What things can you try with your mystery rock to help you identify it? Which rock is it similar to? How can you find out for sure? Are you sure that this rock is what you identified? How could you prove it? What is the evidence? Concepts to be Assessed (Unifying concepts/big ideas and science concepts to be assessed using the Science Exemplars Rubric under the criterion: Science Concepts and Related Content) Physical Science Properties of Matter: Students observe the properties and characteristics of rocks to make predictions and classify materials. Design Technology Use of Tools: Students understand that tools are invented to extend our senses and our abilities (to observe things, to make things, to move things, to shape materials). Students perform tests to determine hardness and the presence of calcite (calcite is a mineral). Scientific Method: Students observe and explain reactions when variables are controlled (cause and effect). Students describe cause-effect relationships with some justification using data and prior knowledge. Earth Science Earth Structure and System: Students observe physical properties of rocks in order to understand their formation through being compacted, heated and/or recrystalized into new rock. Students use the terms rocks, hardness, luster, crystals and minerals appropriately. Mathematics: Students collect, organize and analyze data and can use precise measurements and diagrams appropriately. 5 of 13

Skills to be Developed (Science process skills to be assessed using the Science Exemplars Rubric under the criteria: Scientific Procedures and Reasoning Strategies, and Scientific Communication Using Data) Scientific Method: Observing/sorting/classifying, manipulating tools, conducting tests, collecting and recording data, drawing conclusions, and categorizing based upon observation and results. Other Science Standards and Concepts Addressed Scientific Method: Students describe, predict, investigate and explain phenomena. Scientific Theory: Students look for evidence that explains why things happen and modify explanations when new observations are made. Physical Science Properties of Matter: Students describe and sort objects and materials according to observations of similarities and differences of physical properties. Students observe and describe physical properties of rocks and minerals. The Designed World: Students use tools to extend their senses, to gather, organize, analyze and interpret data. Earth Science Earth Structure and System: Students describe the rock cycle : old rocks at the earth s surface, weather forming sediments that are buried, then compacted, heated, and often recrystalized into new rock. Communication: Students use verbal and nonverbal skills to express themselves effectively. Suggested Materials For this task, teachers will need to use a rock kit or other source for the 14 rocks. There should be enough rocks for each group of two to have one of each of the 14 rocks. Many science product companies have rock kits available. (You may want to try to get a kit with rocks native to your state. State geologists often can help with this.) The kit used in this task came from Scott Resources. It is helpful to keep the group of 14 rocks in baggies so they do not get mixed up. You will also need a source of mystery rocks. These will be the same as the 14 from the kit but may appear somewhat different in size and shape and even color. Materials needed: Rock kit with 14 types of rocks and baggies for storage Collection of same rocks to use as mystery rocks Identification flowchart (see page 9) Mystery rock recording sheet 6 of 13

Magnifying glass Dissecting microscope Chisel and hammer for splitting rocks open (and newspaper to wrap rocks for splitting) Safety goggles Vinegar (and small cups) Nails, pennies, glass for scratching Field guides of rocks and minerals Trays for placing rocks on Category sheet for organizing Possible Solutions A correct solution will be one that includes a drawing, a correctly identified rock and an identification supported by evidence from detailed observations and discussion of the rock s properties. Teachers should be able to use the flowchart to verify much of the information that students provide. Task-Specific Assessment Notes Novice This assessment indicates that the student is able to use the chart to correctly identify the rock but is not able to use the information on the chart to support scientific reasoning. The student is not able to record detailed observations and properties. A picture is included. Only one observation is recorded, and no properties are identified. The observation is not detailed. The rock is correctly identified, but no supporting evidence is given. Apprentice This assessment indicates that the student is able to use the chart to correctly identify the rock but is not able to use the information on the chart to support scientific reasoning. The student is able to record detailed observations and properties. A picture is included. A number of observations are recorded, and one property is identified. A few observations may be incorrect. The rock is correctly identified, but no supporting evidence is given. Practitioner This assessment indicates that the student is able to use the chart to correctly identify the rock, supporting conclusions with evidence from the chart. The student is able to record detailed observations and properties. A picture is included and shows some detail. A number of observations and properties are recorded. Observations include some detail. The rock is correctly identified, and some supporting evidence is given. 7 of 13

Expert This assessment indicates that the student is able to use the chart to correctly identify the rock, supporting conclusions with evidence from the chart. The student is able to record detailed observations and properties. Two pictures are included to show two views. Observations are detailed and descriptive. A number of observations and properties are recorded. The rock is correctly identified, and supporting evidence is given. There is evidence that students tested with vinegar and recorded results. 8 of 13

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Novice 10 of 13

Apprentice 11 of 13

Practitioner 12 of 13

Expert 13 of 13