Geology, Part 1: Can You Categorize Different Types of Rocks? You and your partner will select approximately 20 rocks for your collection. Once you have these rocks, you will need to sort them into categories. You will decide on the name of the category based on what you observe about the rocks, their physical properties and the tests you conducted. You will record your categories, diagrams and observations as well as the properties of the rocks. 1 of 11
Geology, Part 1: Can You Categorize Different Types of Rocks? Suggested Grade Span 3 5 Task You and your partner will select approximately 20 rocks for your collection. Once you have these rocks, you will need to sort them into categories. You will decide on the name of the category based on what you observe about the rocks, their physical properties and the tests you conducted. You will record your categories, diagrams and observations as well as the properties of the rocks. 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 Time Required for the Task Approximately two 45-minute sessions. 2 of 11
Context This task was given to students during a unit on geology. Before this task, students had investigated individual rocks by using different tools and tests to find out what kind of rocks they were. (Tests included scratching the surface with a nail for hardness testing, testing for calcite and looking for minerals.) 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. In this task, students were asked to apply their knowledge of these tools and tests and their understanding of rocks and minerals to categorize a group of rocks that were new to them. What the Task Accomplishes This task serves three purposes. The first was to assess how effectively students can categorize groups of rocks by observing characteristics and properties. The second was to assess students' ability to provide detailed observations of these characteristics and properties. And the third was to assess students use of tools and tests to determine the physical properties of these rocks. How the Student Will Investigate Students worked in groups of two during this activity. Before beginning, the whole class brainstormed a list of some of the things they might look for and test. We listed these on chart paper so that the groups could refer to them. All the materials they would need were available to them. Then from a large assortment, the groups selected 20 rocks to group and categorize. Once they had their rocks, students observed them carefully using tools such as dissecting microscopes and magnifiers. Students observed things such as texture, number and type of layers, color, shiny and dull luster, etc. Students were also allowed to break open (this was done by the teacher with appropriate safety equipment) their rocks to observe what was inside. Next, students could select and perform a variety of tests on their rocks. These tests included scratching the surface with a nail, testing for calcite with vinegar, and looking for minerals and the color of these minerals. Field guides were available for students to identify minerals and possibly the rocks themselves. Interdisciplinary Links and Extensions Science For other tasks in geology, see this CD. Language Arts From this activity, students created their own field guide to rocks that they then took with them on a visit to a natural area for field study. Students also practice using published field guides to identify rocks and minerals. 3 of 11
There are a number of books that were shared as well, such as: My Backyard History Book, by David L. Weitzman If You Are a Hunter of Fossils, by Byrd Baylor How to Dig a Hole to the Other Side of the World, by Faith McNulty Under Your Feet, by Joanne Ryder The Magic School Bus Inside the Earth, by Joanna Cole The Rock, by Peter Parnall Mathematics Students weighed and measured their rocks to determine size, diameter, circumference, weight, width and length. These skills helped in their categorizing. Data could be organized in a chart or table, comparing sizes, weights, etc. Social Studies This unit is often done in connection with Vermont history, as well as the history of the earth. Students in this class researched different time periods of Vermont and the types of geological processes that occurred. Students could make geologic maps of their states and show where different rocks are typically found. Timelines could also be made to show different 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 possible properties and characteristics to look for when categorizing their rocks. These include minerals (color and number), layers (number and type), texture and 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. 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? Can you describe the colors? the texture? How might this rock have been formed? What might have made the rock smooth? rough? 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? How will you categorize these rocks? Why did you put this rock in this category? 4 of 11
What name will you give to this category of rock? Have you used the field guide to help you categorize these rocks? 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). Scientific Method: Students observe and explain reactions when variables are controlled (cause and effect). Students describe cause and 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 tests to determine hardness and the presence of calcite (calcite is a mineral). Students use the terms rocks, hardness, luster and minerals appropriately. Mathematics: Students collect, organize and analyze data and can use precise measurements and diagrams appropriately. 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. 5 of 11
The Designed World: Students use tools to extend their senses, to gather, organize, analyze and interpret data. Earth Science Earth Structure and System: Students can 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 the teacher will need to collect a large number of rocks. A good place to find a variety of rocks is by a stream or river. The rocks do not have to be large. The students can also bring in rocks to add to the collection. There should be enough rocks so that each group has 20 rocks. Other materials needed: Magnifying glass Dissecting microscope Chisel and hammer for splitting rocks open (and newspaper to wrap the 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 There is no one right solution. Students will develop and name categories based upon their observations and tests. A correct solution, however, will include different categories that connect to the work that was done, to detailed observations of the categories indicating that the rocks have similarities, and to tests performed to determine similar physical properties. Task-Specific Assessment Notes Novice This assessment indicates that the students have difficulty sorting rocks based upon observation and properties. Students name each category and attempt to sort their collection of rocks accordingly. A picture is included for each category. Few details are included in drawings. Some of the observations are detailed; however, many of them sound the same for different groupings. Category names and general observations do not match in some instances. (Students indicate that the hard rocks get a line in them when scratched.) Categories do not always reflect the observations or physical properties. Students observe that the rocks look like they have some minerals in them, but the category name is called minerals that are not 6 of 11
visible. The same is true for the "rocks that bubble" category there is no indication that the calcite test was performed. Apprentice This assessment indicates that the students are able to sort and categorize rocks, but they do not always apply what they have learned about rocks and testing to these categories. Students name each category and sort their rocks accordingly. A picture is included for each category but lacks distinguishing details. Observations include some details, such as in the soft rock category. Most of the category and general observations match. However, appropriate tests or physical properties are not always noted. The "soft rocks" category does not indicate whether students scratched the rock, only that it was easy to break. The same is true of the "layered rock" category; students do not indicate through their drawings, observations or description of physical properties how many or the type of layering. Practitioner The assessment indicates that students are able to sort and categorize rocks and are beginning to use testing and tools effectively to draw conclusions. Students name each category with appropriate names (and with another of their own more creative name) and sort their rocks accordingly. A picture is included for each category and shows some details. Observations are detailed in each category. Categories, observations and physical properties match. The students indicate that they performed some of the tests and used tools to observe. The students did not perform a calcite test on any of the rocks but did perform the hardness test using a nail. However, no results are indicated from this test. Expert The assessment indicates that students are able to sort and categorize rocks and use testing and tools effectively to draw conclusions. Students name each category with appropriate names and sort their rocks accordingly. A picture is included for each category. Observations are detailed and descriptive. Categories, observations and physical properties match. Students perform a number of tests on their rocks and make extensive observations to add detail to each category. 7 of 11
Novice 8 of 11
Apprentice 9 of 11
Practitioner 10 of 11
Expert 11 of 11