South Carolina ETV

South Carolina ETV
1101 George Rogers Boulevard
Columbia, SC 29201-4761
Phone: 803-737-3545

Mystery Minerals (Grade 8)

Master Teacher

Ashley Holmes

Time Allotment

Two 50-minute class periods

Overview

What is a mineral, really? Many think that it is a rock of some kind. However, minerals make up rocks. In this lesson, students will explore what minerals really are and how they form. They will also discover how minerals can be classified according to some very specific physical properties. A dichotomous key will be used to help classify various "mystery minerals."

Subject Matter

Earth Science

Learning Objectives

Students will be able to:

Identify rocks and minerals.
Distinguish between rocks and minerals.
Identify and classify minerals according to their physical properties.
Classify minerals by their physical properties using a dichotomous key.

South Carolina Curriculum Standards

(These Standards are found online at http://www.myscschools.com/offices/cso .)

Unit of Study: Earth Processes

• Structure of the Earth System

• Some changes in the solid Earth can be described as the "rock cycle." Old rocks at the Earth's surface weather, forming sediments that are buried, then compacted, heated, and often recrystallized into new rock. Eventually, those new rocks may be brought to the surface by the forces that drive plate motions, and the rock cycle continues.

• Identify and classify minerals that form rocks and explain how

recrystallization of these minerals can take place.

• Distinguish minerals by their physical properties with a dichotomous

key.

Media Components

Video

Basics of Geology: All About Rocks and Minerals .

"Classifying Minerals." This video clip looks at the different sizes and shapes that rocks and minerals come in and how scientists classify them.

To access this clip, log on to your account at ETV's StreamlineSC Web page ( http://etv.streamlinesc.org ). In the search by keyword box, type in Basics of Geology: All About Rocks and Minerals. Click the program title and that takes you to a list of the program's video segments. Download "Classifying Minerals."

(Note to Teacher: If you don't have an account with ETV's StreamlineSC , check with your media specialist about signing up for an account.)

Web Sites

Rocks and Minerals Dictionary

http://www.zoomschool.com/geology/rocks/glossary/

This site is an A to Z online dictionary that describes everything you would need to know about rocks and minerals. It contains several real pictures and descriptions of common minerals.

Rocks and Minerals

http://sln.fi.edu/qa97/spotlight1/spotlight1.html

The Franklin Institute Online allows you to explore the diversity of minerals through a Mineral Gallery and Geology Museum. Each stop is extremely informative and easy to navigate.

US Geological Survey

http://interactive2.usgs.gov/learningweb/students/index.htm

The USGS provides students the opportunity to learn more about minerals and how they are used. There is an interesting trivia game for students to play.

Minerals in Sports

http://minerals.usgs.gov/minerals/pubs/general_interest/

Athletes want to know how minerals are relevant to their interest. Find how minerals play a part in baseball, golf, weightlifting, tennis, using a pogo stick and more.

Materials

Various samples of minerals (e.g., graphite, gypsum, quartz, talc, etc.) for students to use to make observations
Per Group: Mineral Testing Kit (magnifying glass, copper penny, iron nail, streak plate, and glass plate) to perform tests on minerals
Mystery Minerals Data Sheet on which to record mineral properties
Dichotomous Key
Samples of specific minerals for each group: Apatite, Pyrite, Fluorite, Graphite, Magnetite, Feldspar, Galena, Talc, Mica, Calcite, and Quartz. ( Note to Teacher: These are very specific samples of minerals included on the Dichotomous Key. You do not have to use these specific minerals if you do not have access to them. You could replace them with another mineral on the key.)

Equipment

Computer with Internet access to share video from ETV's StreamlineSC
LCD projector

Prep for Teachers

• Make sure that you have access to ETV's StreamlineSC . If you do not have access, check with your district technology person. Every school in South Carolina has a school code to gain access.

• Prepare samples of minerals for each group.

• Prepare mineral samples for classification with the Dichotomous Key before hand. Also make sure that you have the Minerals Kits prepared so students can test their minerals.

• When using media, provide students with a Focus for Media Interaction , a specific task to complete and/or information to identify during or after viewing of video segments, Web sites, or other multimedia elements.

Introductory Activity

Step 1: Place students in groups of four. Give the student groups samples of various minerals to make observations. Do not tell them that they are minerals. You may want to provide each group with a small hand lens so they can make careful observations. Ask the students what does it mean to classify objects? (Accept appropriate responses such as to put them into groups according to how they are alike, to group them, to categorize them.)

Step 2: Tell the students that the objects before them must be classified. Have the groups explore classification systems for the objects before them. They will create their own systems that the objects may be grouped in. Give the students time in their groups to classify the objects. Ask the students to share with the class their classification systems. Allow all groups to share. Ask the class: "How did you decide upon that particular classification system?" (Accept all responses.)

Learning Activity

Step 1: Say: "Now that we have tried to create a classification system for these objects, we are going to learn what they really are. We are going to watch part of a video to discover how these objects were formed and what their characteristics are.

Step 2: Ask the students what do you think these objects are? (Accept all answers; most students will say that they are types of rocks.) Provide the students with a Focus for Media Interaction by asking them to see if any of their objects are found in the beginning of the video clip. PLAY the video. PAUSE when you see a wide sample of minerals and you hear, "they make up 95 percent of all rocks in existence."

Step 3: Ask the students did they find out what their objects were? (Accept answers of minerals.) Do you think that these minerals are useful in any way to us as humans? (Accept all answers.) Let's see if they have specific uses. Provide the students with a Focus for Media Interaction by asking the students to look for at least one use of a mineral. PLAY video and PAUSE when you see a green necklace lying on a rock and you hear, "gemstones and jewelry are just a few of these treasures."

Step 4: Ask the students what did you learn about some of the uses of minerals? Are they used for anything important? (Accept answers of extracting metallic elements for objects, chemical compounds for flavoring our foods, graphite found at the core of all pencils, and for gemstones and jewelry.)

Step 5: Now that we know what our objects are, how might we learn what their actual types are? We know that rocks are grouped into categories of igneous, metamorphic, and sedimentary rocks. We also know that rocks have specific names. Do you think that this is true of minerals? (Accept all answers and guesses.) Provide the students with a Focus for Media Interaction by asking them to find several ways that scientists and geologists may test minerals to find out what they are. PLAY video and PAUSE video at the end of the clip.

Step 6: Ask students what they learned about classifying minerals. Have the students share ways in which minerals are classified. (Accept answers such as by color, hardness, streak, luster, cleavage, and crystal structure.)

Culminating Activity

(Note to teacher: Before the Culminating Activity can occur, students must be given the opportunity to experiment with testing these mineral properties on actual mineral samples. Below is helpful information that can be used in helping students learn how to classify minerals according to the properties of color, luster, cleavage, hardness, streak, and crystal structure.)

Color

This physical property is not so effective in identifying minerals. Colors are subjective to the observer, and unreliable for many minerals. It is simply the color of the mineral on the outside.

Luster

The appearance of a mineral's surface in reflected light.

Metallic Luster: These minerals reflect light effectively and have a metallic look to them.

Non-Metallic Luster: The most common are:

Adamantine = brilliant, like a polished diamond.
Vitreous = glassy, like glazed porcelain or quartz.
Earthy = dull, little reflection.
Pearly = similar to natural pearls.

Streak

This is the color of a mineral when powdered. To discover the streak of a mineral, simply drag the mineral across a streak plate or unglazed tile. The color that occurs on the tile is the color of the mineral's streak.

Hardness

This is the resistance of a mineral to scratching. Hardness is evaluated on a scale from 1 to 10. Lower numbers indicate less resistance to scratching. Each mineral on this scale can scratch a mineral with an equal or lower number, but none with a higher number.

Use consistent pressure in testing for hardness. Make a small scratch about a 1/4-inch long with another mineral to compare hardness or with a known hardness object such as a steel nail to approximate the hardness of the mineral being tested. Wipe any apparent scratches with your finger to make sure the mark is genuine.

Moh's Hardness Scale

Hardness	Mineral	Scratched with:
1	Talc	ordinary pencil lead
2	Gypsum	fingernail, chalk
3	Calcite	copper penny
4	Fluorite	iron nail, brass
5	Apatite	steel knife blade
6	Feldspar	window glass, steel file
7	Quartz	flint sandpaper
8	Topaz	spinel
9	Corundum	emery sandpaper
10	Diamond	carborundum sandpaper

Cleavage

This is the tendency of a mineral to split along certain planes. Cleavage is determined by the internal atomic arrangement and the bond strength between those atoms. The four most common types of mineral cleavage are: Cubic (three planes at right angles), Octahedral (four planes), Rhombohedral (three planes not at right angles), and One chief direction (one plane).

Fracture

When minerals do not break along smooth, clean planes, the mineral is described as having fracture.

Crystal Form

When minerals are allowed to grow unobstructed they will develop into a specific form that depends on their atomic arrangement.

Step 1: Allow students to use what they have learned about the properties of minerals to begin making observations of the samples of minerals provided for them. (Apatite, Pyrite, Fluorite, Graphite, Magnetite, Feldspar, Galena, Talc, Mica, Calcite, and Quartz)

Step 2: Students will record their observations and findings of their testing on the data collection sheet (Mystery Minerals sheet).

Step 3: After the students have recorded all of their observations of the appropriate properties, they will then use the Dichotomous Key to identify the minerals. Students will be able to identify each mineral using this key.

Cross-Curricular Extensions

Math: Have students explore the crystal structure of many minerals. Students can identify the geometric shapes of the crystals. Students may also measure and identify the angles found in the crystals.

Language Arts: Research the uses of a mineral. Write a persuasive essay that will identify the importance of this particular mineral. How useful is it?

Community Connections

Invite a geologist into the classroom to talk about the formation of minerals. Ask him or her to share with the students how he or she tests the minerals to identify them.
Take the students on a field trip to an area where geologic features are prominent. (For example Table Rock in the Upstate of South Carolina) Have the students identify rocks in the area and also try to identify what minerals make up those rocks.

Student Materials

Mystery Minerals Data Sheet (PDF)
Dichotomous Key (PDF)