Can Rocks Gain Weight?

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Ezra Lang
6 years ago
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1 We have been investigating properties of common rocks and minerals. Now it is your turn to design and conduct your own investigation to answer the question, Would rocks gain weight if they were soaked in water? Make sure that you include the following in your investigation: A clear description of the investigation you will conduct A prediction (hypothesis) telling what you think will happen in the investigation A description of the variables you will control A data table to record the data you collect; as an option you may graph the data A conclusion, based on the data, that accepts or rejects your hypothesis 1 of 17

2 Suggested Grade Span 6 8 Task We have been investigating properties of common rocks and minerals. Now it is your turn to design and conduct your own investigation to answer the question, Would rocks gain weight if they were soaked in water? Make sure that you include the following in your investigation: A clear description of the investigation you will conduct A prediction (hypothesis) telling what you think will happen in the investigation A description of the variables you will control A data table to record the data you collect; as an option you may graph the data A conclusion, based on the data, that accepts or rejects your hypothesis Big Ideas and Unifying Concepts Cause and effect Design Models Physical Science Concept Properties of matter Earth Science Concept Earth's systems 2 of 17

3 Mathematics Concepts Computation Data collection, organization and analysis Graphs, tables and representations Measurement Time Required for the Task Two to three hours. Context As part of a rock and mineral unit, students investigated the properties of common rocks and minerals, including quartz, feldspar and types of mica. They also studied igneous rocks, such as granite sandstone, limestone and shale; sedimentary rocks, such as shale, marble, gneiss and schist; and metamorphic rocks, such as slate. Some of the investigations students conducted included comparing the mass and volume of rocks and minerals, observing the physical properties of rocks and minerals, and conducting tests on minerals to determine their hardness, streak, luster, color and reactions to vinegar. Other properties explored were presence of talc, sulfur, magnetite and halite. Students also learned about the forces of weatherization that can cause a rock to break down and eventually form soil (the rock and soil cycle). They were introduced to the idea that freezing and thawing can assist in this process. Students observed water in a container expanding when it turned to ice and observed that this process exerts a force on the container. Students understood that water will seep into a rock and then break the rock apart when it freezes. Yet, students were not always able to observe visually the minute openings in the rock surface, so this investigation provides evidence of the existence of a rock's porosity. Students learned that some types of rocks are more porous than others and that rocks that are weathered will usually be porous by condition. What the Task Accomplishes In this assessment task, students conduct an investigation using the skills and strategies of scientific inquiry to answer a question related to a property of rocks. This task assesses their understanding of the scientific method, their ability to design and conduct an investigation, and their understanding of controlling variables. It also assesses their ability to use tools, collect and record data, and draw conclusions from the data to make inferences about the porosity of rocks. How the Student Will Investigate Students will plan an investigation to answer the question, "" They will make a hypothesis about what they think will happen and plan how they will control variables 3 of 17

4 during their test of the porosity rocks. Students will then collect the materials and/or tools they need and conduct their investigation. They will create a means for recording data and collect the data from their tests. They will then analyze their data and draw a logical and relevant conclusion about the porosity of rocks. Interdisciplinary Links and Extensions Science Students can be introduced to the topic of fossils as well as to the physical and chemical weathering of rocks and the history of our earth. Outside explorations also allow the students to observe firsthand signs of weathering, erosion, deposition and soil composition. Students could also create their own rock and soil identification keys and geologic maps of the school grounds, using county soil maps as a resource. Social Studies Ask students to investigate and research the geological history of an area, and ask if they can find any evidence that it has affected economic development, the use of natural resources, legal policies, etc. (mining, agriculture, tourism, etc.) Mathematics In this task students can use a balance for careful measurement of mass. Teaching Tips and Guiding Questions If you do not have enough equipment for all students to use, they can share the equipment after they have designed their investigations and are given different rocks to test. Before this task students should have had ample opportunities to design and conduct investigations. Possible guiding questions to ask students include: What do you already know about the properties of rocks? How will this knowledge help you form a hypothesis? What materials and/or tools will you need for your investigation? How will you ensure that your tests are fair? What variables will you control? What will you keep the same and what will you change? How will you record your data? What does your data tell you? What can you infer from the data? What will your conclusion be? Does your data support your hypothesis? Why or why not? What did you learn about the porosity of rocks? 4 of 17

5 Concepts to be Assessed (Unifying concepts and big ideas and science concepts to be assessed using the Exemplars Science Rubric under the criterion: Science Concepts and Related Content) Earth Science Earth Systems: Students can identify the characteristics of rocks that reveal information about their composition (minerals; plant and animal remains) and formation (erosion, transport, deposit, pressure, temperature, etc.). Physical Science Properties of Matter: Students observe, identify and classify rocks and minerals according to their properties. Mathematics: Students use precise measurements and the concept of computation. Students collect, organize and analyze data appropriately and use graphs, tables and representations. Skills to be Developed (Science process skills to be assessed using the Exemplars Science Rubric under the criteria: Scientific Procedures and Reasoning Strategies, and Scientific Communication Using Data) Scientific Method: Observing, predicting, hypothesizing, planning and conducting investigations, controlling variables, using tools, collecting and recording observations and data, using data to construct a reasonable explanation, drawing conclusions, making inferences, communicating findings and challenging misconceptions. 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 Systems: Students can understand and explain that rocks are composed of different combinations of materials (minerals; plant and animal remains) and are formed and acted upon by many different forces and events over time (erosion, transport, deposit, pressure, temperature, etc.). Communication: Students use verbal and nonverbal skills to express themselves effectively. 5 of 17

6 Suggested Materials Rock samples between 5 and 30 grams (have a variety of igneous, sedimentary and metamorphic rocks available, such as pumice, obsidian, granite, sandstone, shale, limestone, slate, marble and gneiss) Containers Water Balances Possible Solutions Investigation designs will vary. Students should make a prediction/hypothesis about the question before testing the rocks. They should find and record the mass of each rock they test both before and after soaking the rock in water. They may determine the amount of time they will soak the rocks, but students should ensure fair testing by soaking each rock for the same amount of time. Students should also collect and record data about the mass of the rocks both before and after soaking. From this, they can infer that the added mass is due to water that has been absorbed by the rock during soaking. They should also infer that the rocks are porous, thus allowing water to seep into the small spaces. Data tables should be shown, and it should be clear that a logical process was used throughout the investigation. Conclusions should be based on data. Task-Specific Assessment Notes Novice The student does not include a hypothesis. The explanation of the procedure is vague and missing information, such as the variables that were controlled. The data table shows inaccurate results. The use of tools is inappropriate and leads to incorrect results. The student's conclusion is not logical or relevant. There is little evidence of understanding and application of the scientific method. Apprentice The student includes a hypothesis, but the rationale for the hypothesis is inaccurate. The explanation of the procedure is vague and missing information, such as the variables that are controlled. The data table is clear and shows accurate results. The student's use of tools is appropriate and leads to correct results. The student's conclusion is logical and relevant. There is some evidence of understanding and application of the scientific method. Practitioner The student includes an appropriate hypothesis. The explanation of the procedure is correct, except for the identification of the variables to be controlled. The data table is clear and shows accurate results (but should show differences in mass). The use of tools is appropriate and leads to correct results. The student's conclusion is logical and relevant. There is some evidence of understanding and application of the scientific method. 6 of 17

7 Expert The student includes an appropriate hypothesis. The explanation of the procedure is correct, and variables are controlled. The data table is clear and shows accurate results. The use of tools is appropriate and leads to correct results. The student's conclusion is logical and relevant. There is strong evidence of understanding and application of the scientific method. 7 of 17

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Follow the instructions to determine if your sample is metamorphic, sedimentary or igneous rock.

Follow the instructions to determine if your sample is metamorphic, sedimentary or igneous rock. To gather some appreciation of our world, especially our rock world, we are going to gather an assortment of rocks from our campus. You will use a rock key to classify some of the samples we collect. Procedures: