Edible Rocks: How Can a Cookie Be a Model of a Rock? For this investigation, we will be learning about models. A model is a representation of something that is too difficult to study otherwise. For example, if you wanted to create a new kind of airplane, would you create a design, build it and hope it would fly? It would be wiser to create a smaller version of the airplane to test first! Today, we will be looking at models of rocks. We will be taking apart our rocks to look at the minerals within them. We will use these models because tearing apart rocks is a much more difficult task for which we do not have the equipment. Plus, rocks do not taste so good! We will use toothpicks to carefully pick our rocks apart. Separate each of the minerals you find into separate piles. The minerals will then be separated from the dough, or matrix, of the rock. After we have dissected the rocks, we will use Tcharts to record our results. Each person will receive a model, and each person will record his/her own findings. After you record what minerals you have found, you will graph your results along with two other students results. As these rocks all came from the same batch, the differences we find among the rocks will be important to get a better idea of what most of these rocks look like. 1 of 16
Then we will make some conclusions about our rocks. What minerals are generally in these rocks? Then new questions! Could we use this model to discover other facts about rocks? 2 of 16
Suggested Grade Span 6 8 Task For this investigation, we will be learning about models. A model is a representation of something that is too difficult to study otherwise. For example, if you wanted to create a new kind of airplane, would you create a design, build it and hope it would fly? It would be wiser to create a smaller version of the airplane to test first! Today, we will be looking at models of rocks. We will be taking apart our rocks to look at the minerals within them. We will use these models because tearing apart rocks is a much more difficult task for which we do not have the equipment. Plus, rocks do not taste so good! We will use toothpicks to carefully pick our rocks apart. Separate each of the minerals you find into separate piles. The minerals will then be separated from the dough, or matrix, of the rock. After we have dissected the rocks, we will use T-charts to record our results. Each person will receive a model, and each person will record his/her own findings. After you record what minerals you have found, you will graph your results along with two other students results. As these rocks all came from the same batch, the differences we find among the rocks will be important to get a better idea of what most of these rocks look like. Then we will make some conclusions about our rocks. What minerals are generally in these rocks? Then new questions! Could we use this model to discover other facts about rocks? Big Ideas and Unifying Concepts Change and constancy Models Earth and Space Science Concept Earth structure and system Mathematics Concepts Data collection, organization and analysis Graphs, tables and representations 3 of 16
Time Required for the Task Two periods of 45 minutes each. Context Students have begun their study of rocks and minerals. We have previously classified rocks and minerals and have defined the two terms so that they understand the differences. We have looked at minerals, and have discovered the different properties of these. What the Task Accomplishes The science objectives of this lesson are twofold. First, the knowledge of rocks and minerals (and their differences) will be reinforced. By tearing apart these rocks, students will see how the minerals make up the rock. (This can be connected further to the cookie dough as the matrix of the rock, the glue that holds a conglomerate together.) Second, students will use a model to extend their conceptual understanding. With this introduction to models further lessons can take place in either using models or creating them. How the Student Will Investigate This is an experiment that has been used in a variety of mediums. After a review of rocks and minerals, I have students brainstorm models (buildings, movie sets, etc.) and why they are used. Then I hand out hunks of granite. We discuss how it would be difficult to extract the minerals from this rock. So, I suggest a model. I hand out the enclosed sheet, Edible Rocks, and discuss how we will use a cookie ( A cookie! they exclaim) for a model of a rock. The students get a napkin (or plate), a toothpick and their cookie. They carefully extract the minerals and place these minerals in separate piles. They record their data on the T-charts provided. After they have recorded their own results, they collect data from two other people and record those. Then they eat their cookies. This ends the first lesson. After a review of what we did the previous lesson, students graph their results alongside the results of their partners. We discuss which minerals were most often found and what this could mean with rocks found in the world. Conclusions are drawn about the use of these models and further questions are brainstormed. Interdisciplinary Links and Extensions Science Have students create models of rocks with different compositions of minerals and/or models of different types of rocks (i.e., sedimentary, metamorphic, etc.). Mathematics and Technology Students graph results to show patterns. Students could use computers to organize, analyze and interpret data. 4 of 16
Teaching Tips and Guiding Questions During the lesson, emphasize to students that they should be careful extracting their minerals. The use of a toothpick assists this, as you can t go too quickly with something so small. Emphasize that they are using this as a model. Ask questions such as: How would this model help others to learn about minerals and rocks? Can you tell me something about cookies from the same batch? How about minerals from the same batch of molten rock? Are all rocks of the same type really the same? Why or why not? Once they are finished dissecting and recording, ask students to extend their study by trying to put the cookie back together without the minerals. This can simulate the extraction of minerals from the earth and the difficulties with reclaiming the land. 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) 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 minerals, rocks and conglomerates appropriately. Students describe cause-effect relationships with some justification, using data and prior knowledge. Scientific Method: Students determine the patterns and/or which kinds of change are happening by making a graph or table of measurements (change and constancy). Students see that how a model works after changes are made to it may suggest how the real thing would work if the same thing were done to it (with the extension of using the cookie as the land and the minerals as the extracted coal, diamonds, etc.). Students see that choosing a useful model (not too simple/not too complex) to explore concepts encourages insightful and creative thinking in science, mathematics and engineering (models). Mathematics: Students identify trends and patterns. Students use tables and graphs to show how values of one variable are related (increase, decrease, etc.) to the values of another. 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, collecting and recording data, measuring/estimating, drawing conclusions, communicating findings and raising new questions. 5 of 16
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. Earth Science Earth Structure and System: Students see that some changes in the solid earth can be described as the rock cycle. Students understand that old rocks at the earth s surface form 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 I provide cookies with parts that do not melt. I used a chocolate chip recipe with chips, M&Ms and cranberries. (Nuts also work, if nut allergies are not a factor.) Students will also need a lab sheet (see page 8), graph paper, rulers, napkins and toothpicks. Possible Solutions Students should be able to accurately collect and display data both in a chart and in graph form. They should also be able to explain why models are used (or why this model was used). Task-Specific Assessment Notes Novice The student s solution is incomplete. Some data is recorded, but it is not accurately displayed on the graph. The student may not have recorded information from more than him/herself. The graph is not complete and is not fully labeled. There is little evidence that the student understands why the model is used and/or cannot communicate what this model shows. Apprentice This student s solution is lacking in detail, although the task is completed. The student attempts to offer one reason for the use of this model, although that reason may be incomplete. The student is able to state some aspects of the data gathered but is unable to clearly articulate a trend or connection between the data and the model. There are some inaccuracies of data displayed on the graph. The student attempts to use the terms rocks and minerals appropriately. Practitioner This student s solution is complete. All data are recorded accurately. The graph is clear and labeled properly. The student shows understanding of the model and its use by making some conceptual connections between the model and the study of rocks and minerals. A correlation between the data and the conclusion is shown. 6 of 16
Expert This student s solution is complete and detailed. There is evidence of use of prior knowledge and experience about rocks and minerals. The graph is clearly labeled and accurate. The student gives a detailed explanation of the relationship between the model and the rocks and minerals and extends thinking to another use of the model. 7 of 16
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