Science Grade 06 Unit 02 Exemplar Lesson 02: Physical Properties of Minerals

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1 Grade 06 Unit 02 Exemplar Lesson 02: Physical Properties of Minerals Unit: 02 Lesson: 02 Suggested Duration: 7 days This lesson is one approach to teaching the State Standards associated with this unit. Districts are encouraged to customize this lesson by supplementing with district-approved resources, materials, and activities to best meet the needs of learners. The duration for this lesson is only a recommendation, and districts may modify the time frame to meet students needs. To better understand how your district may be implementing CSCOPE lessons, please contact your child s teacher. (For your convenience, please find linked the TEA Commissioner s List of State Board of Education Approved Instructional Resources and Midcycle State Adopted Instructional Materials.) Lesson Synopsis In this lesson, students will compare minerals using physical properties. Students will test physical properties, such as streak, color, hardness, cleavage, and fracture. In the previous lesson, students calculated the density of a cube and calculated the density of irregular objects, using volume by displacement. Students will have another opportunity to calculate density in this lesson. TEKS The Texas Essential Knowledge and Skills (TEKS) listed below are the standards adopted by the State Board of Education, which are required by Texas law. Any standard that has a strike-through (e.g. sample phrase) indicates that portion of the standard is taught in a previous or subsequent unit. The TEKS are available on the Texas Education Agency website at Scientific Process TEKS 6.6 Matter and energy. The student knows matter has physical properties that can be used for classification. The student is expected to: 6.6B Calculate density to identify an unknown substance. Supporting Standard 6.6C Test the physical properties of minerals, including hardness, color, luster, and streak. 6.1 Scientific investigation and reasoning. The student, for at least 40% of instructional time, conducts laboratory and field investigations following safety procedures and environmentally appropriate and ethical practices. The student is expected to: 6.1A Demonstrate safe practices during laboratory and field investigations as outlined in the Texas Safety Standards. 6.2 Scientific investigation and reasoning. The student uses scientific inquiry methods during laboratory and field investigations. The student is expected to: 6.2A Plan and implement comparative and descriptive investigations by making observations, asking well-defined questions, and using appropriate equipment and technology. 6.2C Collect and record data using the International System of Units (SI) and qualitative means such as labeled drawings, writing, and graphic organizers. 6.2D Construct tables and graphs, using repeated trials and means, to organize data and identify patterns. 6.2E Analyze data to formulate reasonable explanations, communicate valid conclusions supported by the data, and predict trends. 6.4 Scientific investigation and reasoning. The student knows how to use a variety of tools and safety equipment to conduct science inquiry. The student is expected to: 6.4A Use appropriate tools to collect, record, and analyze information, including journals/notebooks, beakers, Petri dishes, meter sticks, graduated cylinders, hot plates, test tubes, triple beam balances, microscopes, thermometers, calculators, computers, timing devices, and other equipment as needed to teach the curriculum. GETTING READY FOR INSTRUCTION Performance Indicators Last Updated 04/23/13 page 1 of 13

2 Unit: 02 Lesson: 02 Suggested Duration: 7 days Grade 06 Unit 02 PI 02 Test the physical properties of an unknown mineral. Include the following tests: hardness color luster streak cleavage and fracture crystal shape calculation of density Choose an appropriate graphic organizer to record the results of the above. Standard(s): 6.2D, 6.4A, 6.6B, 6.6C ELPS ELPS.c.1C, ELPS.c.1E Key Understandings Minerals have specific properties that can be used to determine their identity and classification. What properties help you to separate different minerals? What makes identification difficult? Minerals have characteristic properties, such as density, that are independent of the amount of the sample. Does the size of a sample change its density? Vocabulary of Instruction minerals hardness luster Mohs' Scale of Hardness cleavage fracture streak Materials calculator (1 per group) colored pencils (per group) file (steel, 1 per group) flashlight (1 per group) graduated cylinder (500ml, 1 per group) granite (1 piece per pair) hand lens (1 per student) mineral sample (1 per group) Mohs hardness set minerals (1 per teacher) nails (10 penny common nails, 1 per group) penny (1 per group) picture (of a diamond, see Advance Preparation, 1 per teacher) piece of carbon (1 per teacher) rulers (metric, 1 per group) steel file (1 per group) streak plate (see Advance Preparation, 1 per group) triple beam balance (1 per group) water (per group) Attachments All attachments associated with this lesson are referenced in the body of the lesson. Due to considerations for grading or student assessment, attachments that are connected with Performance Indicators or serve as answer keys are available in the district site and are not accessible on the public website. Teacher Resource: PowerPoint: Minerals Handout: Physical Properties of Minerals (1 per student) Handout: Mineral Identification Data Table (1 per student) Handout: Testing Mineral Procedures (1 per student) Last Updated 04/23/13 page 2 of 13

3 Handout: Mineral and Element Properties Window Paning (1 per student) Unit: 02 Lesson: 02 Suggested Duration: 7 days Teacher Resource: Evaluate Instructions PI (1 for projection) Resources None Identified Advance Preparation 1. Locate a photograph of a diamond (cut, but not polished- if possible) for projection. You may choose to use the last slide in the Teacher Resource: PowerPoint: Minerals as well. This picture will be projected for student view and observation, so it may be easiest to show this slide. 2. Instead of a streak plate, you may use a ceramic tile or piece of fine-grained sandpaper. 3. Prepare attachments as necessary. Background Information This lesson bundles student expectations that address using physical properties, such as luster, conductivity, malleability, density, hardness, color, streak, cleavage and fracture, and crystal shape, to classify matter. Prior to this unit, students have had many opportunities to explore the concepts of identifying and classifying matter based upon physical properties. The concept of minerals is not addressed in the Earth units for this grade; therefore, the focus is on testing the physical properties, not on the minerals themselves. Additionally, students practice calculating density. After this unit, students will develop understandings of the concepts of elements and compounds. The calculation of density can be used in the next grades, but it is explicitly taught only in and will be tested as a STAAR Grade 8 Assessment Supporting Standard under Reporting Category 1: Matter and Energy. Both the periodic table of elements and formula for calculating density are included in the STAAR Grade 8 Reference Materials. INSTRUCTIONAL PROCEDURES Instructional Procedures ENGAGE Minerals 1. Facilitate a discussion: What is a mineral? (A naturally occurring solid, made up of elements) What is the difference between an element and a mineral? Answers may vary, but may include versions of the following: (Minerals are made of elements.) One example would be diamonds are made of carbon. We have been talking about matter and its physical properties in this unit. In this lesson, we will focus on minerals and their physical properties. Would the physical properties of minerals be different than the physical properties we used to study the elements? Answers may vary. Some students may not know or think that all properties fit all substances. (The correct response would be that since the substances are different, the properties may be different.) Notes for Teacher NOTE: 1 Day = 50 minutes Suggested Day 1 Attachments: Teacher Resource: PowerPoint: Minerals Instructional Notes: The slides on the Teacher Resource: PowerPoint: Minerals show the minerals used on Mohs Scale of Hardness in order from hardness of 1 to 10. Do not share this information with students yet. In order for the PowerPoint presentation to be effective, it is best to project in color, rather than to print slides or slide notes. 2. Before showing the Teacher Resource: PowerPoint: Minerals, Say: As you look at the pictures of the minerals, try to determine what the properties of each sample might be. 3. Show the Teacher Resource: PowerPoint: Minerals. Refrain from explaining luster, hardness, color, or uses yet. These will be explained later in the lesson. 4. Ask students to share some of their ideas about possible properties. Write these on the board. Save the list for use later in the lesson. EXPLORE /EXPLAIN Mineral or Rock 1. Pair students, and give each a hand lens and piece of granite. 2. Instruct students to use the hand lens to make observations about the granite. Suggested Day 1 (continued) Materials: Last Updated 04/23/13 page 3 of 13

4 Instruct students to draw an illustration and color what they see in the field of view of the hand lens: trace the perimeter of the hand lens draw what they see in proportion to the area of view color details accurately label what the drawing represents (magnification of a piece of granite) 3. When students have finished their drawings, Ask: What is granite? (A rock) What do you think the black, pink, white, clear, white, and shiny gray materials are? Answers will vary. Lead students to the idea that these inclusions are minerals. Are minerals and rocks the same? (No. Rocks are composed of one or more minerals. Minerals are naturally occurring, inorganic compounds that are crystalline in form and have a definite composition. Note: This is a more advanced definition that presented in the Engage activity. granite (1 piece per pair) hand lens (1 per student) colored pencils (per group) Instructional Notes: Granite commonly comes in a pink, gray, or white version, but there are many colors of granites. Adjust the question about the colored material in granite according to which granite you have. There are four minerals that make up granite. The activity will address the most common colors. Notebooks: Unit: 02 Lesson: 02 Suggested Duration: 7 days Students make their field of view drawing in the notebook. 4. Post or project the definitions of rock and mineral as written above, and ask students to record these definitions in their notebooks. 5. Instruct students to label their drawings as follows by color: pink (may be glassy looking): Feldspar black or brown: Hornblende shiny gray or clear flecks: Mica milky or clear: Quartz EXPLORE/EXPLAIN Mineral Properties Suggested Day 2 1. Give each student a copy of the Handout: Physical Properties of Minerals. 2. As a class, read the information, and instruct students to create a graphic organizer, such as a bubble map, to condense and organize the information from the reading in their notebooks. Another option would be to have students work in groups, to highlight the most important material on the handout. 3. As you read through the material, work with the students to record the most important information. 4. When the graphic organizer is complete, Ask: What are the properties that were listed on the PowerPoint? (Color, luster, hardness, streak, cleavage, and fracture) What properties were listed in the handout and your graphic organizer? (The same: color, luster, hardness, streak, cleavage, and fracture) Are these properties enough to identify a mineral? It depends on the mineral. The more properties that are used, the more exact the identification. 5. Instruct students to create a T-chart, and put carbon (element) on one side and diamond (mineral) on the other. 6. Show students a sample of carbon, and tell them to list the physical properties on their T-chart. Ask: What are some properties of carbon? (Black, brittle, insulator, dull luster, low density) Materials: piece of carbon (1 per teacher) picture (of a diamond, see Advance Preparation, 1 per teacher) glue or tape (per class) Attachments: Handout: Physical Properties of Minerals (1 per student) Instructional Notes: It is not important for students to memorize the information from the Handout: Physical Properties of Minerals. There is a photograph of an unpolished diamond in the Teacher Resource: PowerPoint: Minerals that may be used for the activity. Notebooks: Students create a graphic organizer in their notebooks. The Handout: Physical Properties of Minerals pages may be affixed to the notebook for reference 7. Project a picture of a diamond, and tell them to list the physical properties in their T-chart (see Advance Preparation). Ask: What are some physical properties of a diamond? (Clear, brittle, insulator, shiny luster, dense) Last Updated 04/23/13 page 4 of 13

5 Unit: 02 Lesson: 02 Suggested Duration: 7 days 8. Explain to students that diamonds are made from carbon, and ask them why they may have such different physical properties. Answers may vary (The correct answer should be the way the elements bond together, but students will not yet have this level of understanding.) 9. Optional: (Time permitting) Demonstrate how to use a streak plate and test minerals for hardness. 10. Direct students to affix the Handout: Physical Properties of Minerals to their science notebooks EXPLORE/EXPLAIN Testing Mineral Properties Suggested Days 3 and 4 1. Place students into groups. The number of mineral samples you have will determine the group size. 2. Distribute a mineral sample to each group. Do not tell groups which mineral they have. 3. Distribute the Handouts: Mineral Identification Data Table and Testing Mineral Procedures to each student. 4. Direct students to read the information for each test and then conduct the tests. Remind students to use caution with the nails and streak plates. If you have not yet demonstrated the use of the streak plate and the hardness test, do so at this time. 5. After students finish testing their minerals, have them trade minerals with another group. Continue this process until the students have tested all of the minerals. 6. If you do not have access to all of the different minerals, then students will be able to fill in the chart using the Mineral Identification Data Sheet with the Teacher Resource: PowerPoint: Minerals. 7. When the testing is complete, Ask: What are the main properties that are used to identify an unknown mineral? (Luster, color, streak, and hardness, fracture, and cleavage) What makes identification of an unknown mineral difficult? Answers may vary but should include: luster and color can be viewed differently by different people, and hardness is not exact but relative to the difference between two other minerals. Some minerals do not leave a streak color. What would make the identification more exact? A greater number of different tests to help identify the mineral would help make the identification more exact. 8. Show the Teacher Resource: PowerPoint: Minerals again. Instruct students to compare their results in the Mineral Identification Data Sheet to the properties listed in the presentation. Instruct students to fill in any missing information on their data sheets. 9. When the table is complete, ask students to share some trends they see in the table. They should see that hardness increases as they move through the table. They may see that color varies. Luster and streak color also vary because those factors depend on the interpretation of what an individual person observes. Materials: Mohs hardness set minerals (1 per teacher) nails (10-penny common, 1 per group) penny (1 per group) streak plate (see Advance Preparation, 1 per group) file (steel, 1 per group) flashlight (1 per group) graduated cylinder (500ml, 1 per group) ruler (metric, 1 per group) triple beam balance (1 per group) Attachments: Handout: Mineral Identification Data Table (1 per student) Handout: Testing Minerals Procedures (1 per student) Teacher Resource: PowerPoint: Minerals (from previous activity) Safety Note: Students should use caution with the nail and streak plate. Instructional Notes: This lesson is based on using a Mohs Scale of Hardness mineral set. The minerals tested from this set and the PowerPoint will make practice identification of a mineral easier. The lesson can be done with other minerals, but identification will be more difficult. Students should not be accountable for knowing the different types of cleavage and fracture. They may need assistance with this portion of the table. When streak plates get dirty, they can be cleaned by scrubbing them with an old toothbrush. You can also use some sand with the water to scour off resistant streaks. Allow it to dry before using. Notebooks: Students will affix the Handout: Mineral Identification Data Table in their notebooks. ELABORATE Window Paning Suggested Day 5 Last Updated 04/23/13 page 5 of 13

6 1. Instruct students to create pictures and complete the Handout: Mineral and Element Properties Window Paning. 2. Instruct students to write a short essay or summary explaining the physical properties of a mineral of their choosing. Give students a sentence stem, such as the following, to assist them with beginning the essay: Attachments: Unit: 02 Lesson: 02 Suggested Duration: 7 days Handout: Mineral and Element Properties Window Paning (1 per student) Minerals such as (mineral name) can easily be identified by their physical properties such as 3. Assist students as they write the essays. You may want to assign these to be completed for homework. EVALUATE Testing an Unknown Suggested Days 6 and 7 Grade 06 Unit 02 PI 02 Test the physical properties of an unknown mineral. Include the following tests: hardness color luster streak cleavage and fracture crystal shape calculation of density Choose an appropriate graphic organizer to record the results of the above. Standard(s): 6.2D, 6.4A, 6.6B, 6.6C ELPS ELPS.c.1C, ELPS.c.1E 1. Refer to the Teacher Resource: Evaluate Instructions PI for information on administering the performance assessment. Materials: mineral sample (1 per group) rulers (metric, 1 per group) triple beam balance (1 per group) water (per group) calculator (1 per group) streak plate (see Advance Preparation, 1 per group) nails (10 penny common nails, 1 per group) penny (1 per group) steel file (1 per group) flashlight (1 per group) graduated cylinder (500 ml, 1 per group) Attachments: Teacher Resource: Evaluate Instructions PI (1 for projection) Instructional Notes: If the minerals from the mineral set were used, the PowerPoint may be shown again to allow students to compare their data to that on the PowerPoint. Students may need to reference the Mineral Testing Procedures Handout to complete the Performance Indicator. Last Updated 04/23/13 page 6 of 13

7 Physical Properties of Minerals Unit: 02 Lesson: 02 There are many properties that can be used to identify minerals, but any one property is not enough to identify an element. Some of the properties used in mineral identification are: fracture, cleavage, specific gravity, crystal structure, magnetism, transparency, radioactivity, inclusion, reaction to acid, color, streak, luster, and hardness. The following four properties will be studied: Color Color is the most obvious but least dependable property of mineral. Some minerals, such as gold, only come in one color. Other minerals have a wide variety of colors such as calcite, which can be pink, orange, blue, green, red, brown, white, or clear. Sometimes, other elements can cause a change in color. For example, pure quartz is clear. If iron was present when the quartz formed, the color of the quartz will be purple. The purple quartz is called amethyst. Some minerals will have a different color if viewed under an ultraviolet light. These minerals are said to be fluorescent. Streak The color of crushed mineral powder is known as the mineral s streak. A mineral is scraped across a streak plate to see what color it leaves. The color of a mineral s powder streak is important for identifying minerals in two ways. First, the color of the streak may be different than the color of the element. Second, nearly every mineral has a streak color that stays the same regardless of the color of the mineral. For example, calcite comes in a wide range of colors, but its streak color will always be white. Streak plates are small squares of white, unglazed porcelain, like the underside of a ceramic bathroom tile. Since the plate is white, dark color streaks will show up well. A mineral that streaks white or clear cannot be tested this way. Streak is most useful in identifying dark-colored minerals. If a streak plate is not available, a piece of fine grained sandpaper will work for the softer minerals. Cleavage and Fracture Minerals are made of crystals, and when the crystal is broken, it reveals a particular crystal shape. This shape is known as cleavage. All minerals do not have cleavage. If the mineral does not have any crystallized fragments, then it does not have cleavage. Describing the way a mineral is broken is known as fracture. Different minerals break in different ways. Fracture can be described as smooth, irregular, jagged, or splintery. Fracture can be used to describe the way a mineral breaks when it does not have cleavage. Luster The way the surface of a substance reflects light is called luster. Luster is used to describe how a mineral looks. It is impossible to identify minerals that have the same luster on this characteristic alone. There are several descriptors for luster. Some categories of luster are: metallic opaque; reflects like metals; metal elements exhibited vitreous glassy; applies to about 70% of all minerals 2012, TESCCC 04/16/13 page 1 of 2

8 adamantine brilliant or diamond-like; high shine silky reflect like silk cloth; minerals have fine fibrous structure pearly similar to a white shirt button, mother-of-pearl dull poor reflectors; minerals have rough, porous texture Unit: 02 Lesson: 02 Hardness Hardness describes how a substance will resist being scratched by another substance. Frederick (Friedrich) Mohs, an Austrian mineralogist, developed a scale to measure hardness in It is known as Mohs Scale of Mineral Hardness, and it is the standard scale for measuring the hardness of minerals. The scale rates minerals 1 through 10, with 1 being the softest and 10 being the hardest. A different mineral is represented by each number, with each one being harder than the previous one. The scale is relative in measurement. A mineral can be more than 3 and less than 4 in hardness. The hardness can be written as a whole number or in half number increments for in-between hardness. Mohs Scale of Mineral Hardness 1 talc 2 gypsum 3 calcite 4 fluorite 5 apatite 6 feldspar 7 quartz 8 topaz Common Items to Use to Test for Mineral Hardness 1 soft, pencil lead 2 2 ½ fingernails 3 3 ½ penny dated prior to ½ 10-penny nail 5 5 ½ penknife blade or glass 6-6 ½ steel file 8 whet stone (sharpening stone) 9 corundum 10 diamond 2012, TESCCC 04/16/13 page 2 of 2

9 Mineral Identification Data Table Unit: 02 Lesson: 02 Mineral Color Luster Talc Gypsum Calcite Fluorite Apatite Orthoclase (Feldspar) Quartz Topaz Corundum Ex. Diamond Clear Glassy Streak (color) Harder than streak plate Hardness Cleavage Fracture Density 10 Yes Conchoidal 3.5g/ml 2012, TESCCC 06/06/12 page 1 of 1

10 Testing Minerals Procedures Unit: 02 Lesson: 2 Color Color is the most obvious but least dependable property of mineral. 1. Look at the sample. 2. Record the color or colors observed in your Mineral Identification Data Table sheet. Luster Luster describes how the surface of the mineral reflects light. Some of the common terms that are used to describe luster are: metallic (shine like metal), vitreous (glassy), adamantine (brilliant as in a faceted diamond), or dull. 1. Look at the sample surface. 2. Shine a flashlight on the surface of the mineral. 3. Record the luster observed in your Mineral Identification Data Table sheet. Streak Materials: streak plate, mineral Streak color is the color produced by rubbing a mineral on a piece of white, unglazed porcelain. Streak plates have a hardness of about 6.5. If the mineral is harder than the porcelain streak plate, the mineral will not leave a streak. Regardless of the color variety of a mineral, the streak color will remain the same. 1. Record the color of the mineral. 2. Gently drag the mineral over the streak plate. 3. Observe the color of the streak, and record this in your Mineral Identification Data Table sheet. Hardness Materials: fingernail, penny, steel nail, file The hardness of a mineral is its resistance to being scratched by another substance. A mineral will scratch another mineral softer than itself, but not one that is harder. A mineral scratched by a knife, but not by a penny will have a hardness of approximately 4 on the Mohs Scale. The rating of 4 falls between the knife (5.5) and the penny (3). 1. Attempt to scratch the mineral with the object of known hardness (penny, nail, etc). 2. Look for a groove or scratch. Sometimes, a powder will need to be brushed away from the scratched area in order to see if the mineral was really scratched. Use a hand lens, if necessary. 3. If there is no powder or scratch, test with another item of known hardness. 4. Record your observations in your Mineral Identification Data Table sheet. 2012, TESCCC 04/16/13 page 1 of 2

11 Unit: 02 Lesson: 2 Cleavage Minerals are made of crystals, and when the crystal is broken, it reveals a particular crystal shape. If the mineral does not have any crystallized fragments, then it does not have cleavage. 1. Observe the mineral. If it has broken places that seem to break the same way, then it has cleavage. 2. Record a yes or no in your Mineral Identification Data Table sheet if the mineral does or does not have cleavage. Fracture Describing the way a mineral is broken is known as fracture. Different minerals can break in different ways. Fracture can be described as smooth, irregular, jagged, conchoidal, or splintery. 1. Observe the mineral. 2. Describe the way the broken pieces of the mineral look using one of the underlined words. 3. Record your observations in your Mineral Identification Data Table sheet. Density Density is the amount of matter in a given volume. The formula for density is Density = Mass / Volume (D = M / V). Volume can be found using displacement or with the formula Length x Height x Width = Volume. Mass can be measured using a triple beam balance. 1. Find the mass of the mineral using the triple beam balance. 2. Find the volume of the mineral, either by displacement (irregularly shaped) or with the formula (regularly shaped). 3. Put numbers into formula, D = M / V. 4. Record your results on your Mineral Identification Data Table sheet. 2012, TESCCC 04/16/13 page 2 of 2

12 Mineral and Element Properties Window Paning Unit 02 Lesson: 02 Directions: In each of the window panes, draw a picture or sketch to show what the word means. Do not add any words to the box, use only pictures. Hardness Streak Cleavage Fracture Density Luster Brittle Malleable Conductor Insulator Metal Non-metal 2012, TESCCC 06/06/12 page 1 of 1

13 EVALUATE Instructions PI Unit: 2 Lesson: 02 Performance Indicator Test the physical properties of an unknown mineral. Include the following tests: hardness color luster streak cleavage and fracture crystal shape calculation of density Choose an appropriate graphic organizer to record the results of the above. (6.2D; 6.4A; 6.6B, 6.6C) 1C, 1E 1. Share Performance Indicator rubric or expectations with students prior to students beginning the assessment. 2. Answer any questions students may have regarding the assessment. 3. Instruct students to create a data table and include the physical properties for the mineral within the table. Students will add this to their notebooks. 4. Give students a sample of a mystery mineral. Instruct to students complete the Performance Indicator and attempt to identify the mineral by testing for: relative hardness using a field kit consisting of a penny, nail, scissor, glass microscope slide or mirror, and steel file streak color with a streak plate or piece of fine grained sandpaper density of an irregularly shaped object with a triple beam balance, graduated cylinder, and water luster with a flashlight color cleavage fracture 5. The identification of the unknown mineral will be relative to what their testing materials allow. The testing would have to be more extensive to identify the mineral with accuracy. Students may need reference books on minerals and/or time in the computer lab to aid in identification. 2012, TESCCC 04/05/13 page 1 of 1