Download Minerals - GVLibraries

Minerals
Teacher's Guide
Editors:
Brian A. Jerome, Ph.D.
Stephanie Zak Jerome
Assistant Editors:
Anneliese Brown
Louise Marrier
Graphics:
Fred Thodal
Lyndsey Canfield
Dean Ladago
Visual Learning Company
www.visuallearningco.com
1-800-453-8481
25 Union Street
Brandon VT 05733
A Message from our Company . . .
Visual Learning is a Vermont-based, family owned company specializing in the
creation of science programs. As former classroom science teachers we have
designed our programs to meet the needs and interests of both students and
teachers. Our mission is to help educators and students meet educational goals
while experiencing the thrill of science!
Viewing Clearances
The video and accompanying teacher’s guide are for instructional use only. In showing
these programs, no admission charges are to be incurred. The programs are to be
utilized in face-to-face classroom instructional settings, library settings, or similar
instructional settings.
Duplication Rights are available, but must be negotiated with the Visual Learning
Company.
Television, cable, or satellite rights are also available, but must be negotiated with
the Visual Learning Company.
Closed circuit rights are available, and are defined as the use of the program
beyond a single classroom but within a single campus. Institutions wishing to utilize
the program in multiple campuses must purchase the multiple campus version of the
program, available at a slightly higher fee.
Video streaming rights are available and must be negotiated with the Visual Learning
Company.
Discounts may be granted to institutions interested in purchasing programs in large
quantities. These discounts may be negotiated with the Visual Learning Company.
Use and Copyright:
The purchase of this video program entitles the user the right to reproduce or
duplicate, in whole or in part, this teacher’s guide and the black line master handouts
for the purpose of teaching in conjunction with this video, Minerals. The right is
restricted only for use with this video program. Any reproduction or duplication, in
whole or in part, of this guide and student masters for any purpose other than for use
with this video program is prohibited.
The video and this teacher’s guide are the exclusive property of the copyright
holder. Copying, transmitting, or reproducing in any form, or by any means,
without prior written permission from the copyright holder is prohibited (Title 17,
U.S. Code Sections 501 and 506).
Copyright © 2008
ISBN 978-1-59234-182-5
Page
2
Minerals
Visual Learning Company 1-800-453-8481
Table of Contents
Visual Learning Company 1-800-453-8481
A Message from our Company
2
Viewing Clearances
2
Use and Copyright
2
National Standards Correlations
4
Student Learning Objectives
5
Assessment
6
Introducing the Program
7
Program Viewing Suggestions
7
Video Script
8
Answer Key to Student Assessments
12
Answer Key to Student Activities
13
Pre-Test
14
Post-Test
16
Video Review
18
Vocabulary
19
Writing Activity
20
Making Crystals
21
Mineral Identification
23
Exploring Mono Lake
25
Minerals
Page
3
National Standards Correlations
Benchmarks for Science Literacy
(Project 2061 - AAAS) Grades 3-5
The Physical Setting - Processes that Shape the Earth (4C)
By the end of the fifth grade, students should know that:
• Rock is composed of different combinations of minerals. Smaller rocks
come from the breakage and weathering of bedrock and larger rocks. Soil
is made partly from weathered rock, partly from plant remains — and also
contains many living organisms.
The Physical Setting - The Structure of Matter (4D)
By the end of the fifth grade, students should know that:
• Materials may be composed of parts that are too small to be seen
without magnification.
National Science Education Standards
(Content Standards: K-4, National Academy of Sciences)
Earth and Space Science - Content Standard D
As a result of activities in grades K-4, all students should develop an
understanding of:
Properties of Earth Materials
• Earth materials are solid rocks and soils, water, and the gases of the
atmosphere. The varied materials have different physical and chemical
properties, which make them useful in different ways, for example, as
sources of fuel, or for growing the plants we use as food. Earth materials
provide many of the resources that humans use.
Page
4
Minerals
Visual Learning Company 1-800-453-8481
Student Learning Objectives
Upon viewing the video and completing the enclosed student activities,
students will be able to do the following:
• Define minerals as naturally occurring solids that have a definite chemical
makeup and crystal shape.
• Explain that a crystal is made of particles that form a repeating pattern.
• Understand that most minerals are comprised of two or more elements,
which are chemically pure substances.
• Differentiate between silicate and nonsilicate minerals and give examples of
both.
• List and define different mineral properties, such as color, hardness, streak,
and luster.
• Identify common problems associated with classifying or identifying minerals
based on their color.
• Explain how Mohs hardness scale can help determine the hardness of
minerals.
• Differentiate between cleavage and fracture.
• Explain how minerals are formed from molten rock on or beneath Earth’s
surface.
• Understand how changes in temperature or pressure can alter rocks to form
different minerals.
• Know that some minerals form when mineral-rich water evaporates.
Visual Learning Company 1-800-453-8481
Minerals
Page
5
Assessment
Preliminary Test (p. 14-15):
The Preliminary Test is an assessment tool designed to gain an
understanding of students’ preexisting knowledge. It can also be used as a
benchmark upon which to assess student progress based on the objectives
stated on the previous pages.
Post-Test (p. 16-17):
The Post-Test can be utilized as an assessment tool following student
completion of the program and student activities. The results of the
Post-Test can be compared against the results of the Preliminary Test to
assess student progress.
Video Review (p. 18):
The Video Review can be used as an assessment tool or as a student
activity. There are two sections. The first part contains questions displayed
during the program. The second part consists of a five-question video quiz
to be answered at the end of the video.
Page
6
Minerals
Visual Learning Company 1-800-453-8481
Introducing the Program
Before viewing the program, ask students if they know what a mineral is.
Explain that minerals are naturally occurring solids that have a definite
chemical makeup and crystal shape. Minerals are formed by two or more
elements, which are chemically pure substances. Different minerals
combine to form rocks.
Next, ask students to identify minerals they use everyday. Record the list
generated by the class on the board. If students need help getting started,
consider offering the following examples: The mineral graphite is used to
make the lead of pencils. The wiring of most electronics is made of the
mineral copper. Quartz is a raw material of glass and can be found in
mirrors, the face of wrist watches, lightbulbs, and drinking glasses. Salt is
a mineral that is used to add flavor to food. Jewelry can also be composed
of minerals, such as gold, turquoise, and diamonds. Tell students to
pay close attention to the video to learn more about minerals, their
characteristics, how they are formed, and their everyday uses.
Program Viewing Suggestions
The student master “Video Review” is provided (p. 18) for distribution to
students. You may choose to have your students complete this Master while
viewing the program or do so upon its conclusion.
The program is approximately 14 minutes in length and includes a five-question
video quiz. Answers are not provided to the Video Quiz in the video, but are
included in this guide on page 12. You may choose to grade student quizzes
as an assessment tool or to review the answers in class.
The video is content-rich with numerous vocabulary words. For this reason you
may want to periodically stop the video to review and discuss new terminology
and concepts.
Visual Learning Company 1-800-453-8481
Minerals
Page
7
Video Script
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
Page
8
What do copper wire,…
…talcum powder,…
…jewelry,…
…and table salt have in common?
All these things are made from minerals.
So, what exactly are minerals?
What’s the difference between a rock and a mineral?
What are some of the characteristics of minerals?
And how do you go about identifying them?
During the next few minutes, we are going to answer these questions and
others,…
…as we explore the fascinating topic of minerals.
Graphic Transition - What are Minerals?
The mineral turquoise, in this piece of jewelry,…
…and the mineral gypsum, used to make sheetrock, are just two examples of
the more than 3,000 known minerals.
Surprisingly, though, over 90% of the rocks in the Earth’s crust are comprised of
only 20 minerals. These minerals are generally called rock-forming minerals.
Chances are, the rocks you see around your neighborhood are made up of two
or more of these common rock-forming minerals.
For example, this rock, called granite, contains three main minerals: feldspar;
quartz; and black mica, or biotite.
So, what exactly is a mineral?
A mineral is a naturally occurring solid that has a definite chemical makeup and
crystal shape.
Phew! That’s a mouthful! So, let’s break this definition down into smaller pieces.
To start with, minerals are found in nature.
Minerals are also solids with a definite volume and shape.
And minerals have a crystal structure. A crystal is made of particles which form
a pattern that repeats itself over and over.
Sometimes a crystal pattern is quite obvious, as is the case with this quartz
crystal.
But sometimes special microscopes are needed to observe crystal shapes.
Another characteristic of minerals is that they have a definite chemical makeup,
which means they contain specific combinations of elements.
You can think of an element as a chemically-pure substance, like iron.
Most minerals are made up of two or more elements. Quartz, for example, is
made up of the elements silicon and oxygen.
Graphic Transition - Grouping Minerals
As we mentioned, there are thousands of different kinds of minerals.
Geologists often classify them in groups to make them easier to study.
Minerals
Visual Learning Company 1-800-453-8481
Video Script
32. A common way to group minerals is based on their chemical makeup.
33. For example, minerals are often placed into two main groups: silicate minerals
and non-silicate minerals.
34. Silicon, the element in silicate minerals, is very common in rocks.
35. Quartz and feldspar are examples of silicate minerals.
36. Non-silicate minerals do not contain silicon.
37. Sulfur, calcite, and salt are examples of non-silicates.
38. Sometimes scientists group minerals as metallic…
39. ...or non-metallic.
40. Galena and copper are examples of metallic minerals,…
41. ...whereas halite and calcite are non-metallic minerals.
42. Graphic Transition - Identifying Minerals
43. Because there are so many different kinds of minerals, it isn’t always easy to tell
them apart.
44. You Compare! Which of these two minerals is gold?
45. The one on the left is gold. The one on the right looks like gold but is called pyrite,
or “fool’s gold.”
46. Even though these minerals look similar, they have characteristics which make
them different from one another.
47. Each mineral has its own specific properties that can be used to identify it.
48. A property is a characteristic of a mineral.
49. One of the easiest mineral properties to notice is the color of a mineral’s outer
surface.
50. The problem with color, however, is that the same mineral can come in several
different colors.
51. And in some cases, different minerals may have the same color, as we just saw
with pyrite and gold.
52. Sometimes a mineral’s streak is helpful in identifying it. Streak is the color of a
minerals’ powder when rubbed against a piece of porcelain.
53. Notice how this mineral has a shiny metallic appearance,…
54. ...but this mineral has a dull appearance. This property is referred to as luster.
55. Luster is the way the surface of a mineral reflects light. There are many ways that
minerals reflect light.
56. Metallic, nonmetallic, waxy, and earthy are some of the ways we describe a
mineral’s luster.
57. You Observe! Was this mineral scratched with a fingernail or with a steel knife?
58. Your fingernail can’t scratch it, but a steel knife can.
59. This softer mineral, however, called talc, can easily be scratched with a fingernail.
60. Different minerals have varying degrees of hardness.
61. To determine the hardness of minerals, scientists use a scale called Mohs hardness
scale.
Visual Learning Company 1-800-453-8481
Minerals
Page
9
Video Script
62. On this scale, talc is the softest mineral at 1 and diamond is the hardest at 10.
Between these two extremes are other minerals with progressing degrees of
hardness.
63. Different types of minerals tend to break in different ways as well.
64. Notice how this piece of halite…
66. ...and this piece of biotite break along flat planes.
67. You Observe! Describe how this quartz breaks.
68. Quartz breaks unevenly.
69. Fracture is the tendency of minerals to break along irregular or curved surfaces.
70. Another way minerals differ is in the types of crystal structures that they form.
71. There are several different basic crystal shapes.
72. In some cases, minerals can be identified by other properties, such as density,
taste, and odor, to name just a few.
73. Graphic Transition - How Do Minerals Form?
74. Minerals form in a variety of ways.
75. Many minerals are formed from molten rock beneath or above Earth’s surface.
76. When molten rock cools, mineral crystals are formed.
77. Mica, feldspar, magnetite, and quartz are formed when molten rock cools.
78. Changes in temperature, pressure, or chemical makeup inside Earth can also alter
rocks to form different minerals.
79. Garnet, graphite, talc, and magnetite are formed this way.
80. Sometimes minerals form in solutions of mineral-rich water.
81. These formations were formed in Mono Lake, California when the lake was much
deeper.
82. Minerals such as sulfur and iron are often formed in geothermal pools.
83. Sometimes, when mineral-rich water evaporates, it leaves behind mineral crystals.
84. These salt crystals in Death Valley were formed when salt-rich water evaporated.
85. These are just a few examples of how minerals form.
86. Graphic Transition - Summing Up
87. During the past few minutes, we’ve explored some of the fascinating
characteristics of minerals.
88. We saw that minerals are very important substances which make up rocks.
89. Minerals are naturally occurring, inorganic solids that have a definite crystal shape
and a definite chemical composition.
90. We discussed how geologists sometimes classify minerals as silicates or nonsilicates.
91. Minerals possess many different properties, which can be used to identify them.
92. We briefly investigated the properties of color,…
93. ...streak,…
94. ...and luster.
95. We also explored the properties of hardness and the use of Mohs hardness scale.
Page
10
Minerals
Visual Learning Company 1-800-453-8481
Video Script
96. Some of the other properties used in identifying minerals were demonstrated,
including cleavage, fracture, and crystal shape.
97. So, the next time you use something made from minerals,…
98. ...or notice a nice piece of jewelry,…
99. ...think about some of the things we’ve just discussed.
100. You just might think about minerals a little differently.
Graphic Transition - Video Assessment
Fill in the correct word to complete the sentence. Good luck and let’s get started.
1. ________ have a definite chemical makeup and crystal shape.
2. A ______ is a characteristic of a mineral.
3. This mineral has a metallic _______.
4. ________ is the tendency of minerals to break along flat surfaces.
5. When ________ rock cools, mineral crystals form.
Answers can be found on page 12
Visual Learning Company 1-800-453-8481
Minerals
Page
11
Answer Key to Student Assessments
Pre-Test (p. 14-15)
Post-Test (p. 16-17)
1. d - minerals
2. c - elements
3. b - silicon
4. a - properties
5. c - luster
6. d - Mohs hardness scale
7. a - fracture
8. d - molten rock
9. b - streak
10. d - crystal
11. true
12. true
13. true
14. false
15. false
16. Properties used to identify minerals
include color, hardness, streak, luster,
cleavage, fracture, crystal shapes, density,
taste, and odor.
17. Cleavage is the tendency of minerals
to break along flat surfaces. Fracture is
the tendency of minerals to break along
irregular or curved surfaces.
18. Rocks are made up of a mixture of two
or more minerals.
19. Mineral crystals form when molten rock
cools.
20. An element is a chemically pure
substance. A mineral is made of two or
more elements.
1. a - fracture
2. b - streak
3. d - Mohs hardness scale
4. d - molten rock
5. d - minerals
6. b - silicon
7. d - crystal
8. a - properties
9. c - elements
10. c - luster
11. false
12. true
13. false
14. true
15. true
16. Rocks are made up of a mixture of
two or more minerals.
17. An element is a chemically pure
substance. A mineral is made of two or
more elements.
18. Mineral crystals form when molten
rock cools.
19. Cleavage is the tendency of minerals
to break along flat surfaces. Fracture is
the tendency of minerals to break along
irregular or curved surfaces.
20. Properties used to identify minerals
include color, hardness, streak, luster,
cleavage, fracture, crystal shapes,
density, taste, and odor.
Video Review (p. 18)
1. The mineral on the left is gold. The
mineral on the right is pyrite, or fool’s gold.
2. The mineral could not be scratched with
a fingernail, but it was scratched with a
steel knife.
3. Quartz breaks unevenly.
Page
12
Minerals
1. minerals
2. property
3. luster
4. cleavage
5. molten
Visual Learning Company 1-800-453-8481
Answer Key to Student Activities
Vocabulary (p. 19 )
Making Crystals (p. 22)
1. mineral
2. crystal
3. fracture
4. element
5. silicon
6. properties
7. streak
8. luster
9. Mohs hardness scale
10. cleavage
1. Evaporation causes crystals to form
from the salt solution. This is similar
to the process by which sulfur and
iron minerals are formed when water
evaporates from geothermal pools, and
when salt crystals form in shallow pools.
2. The crystals form when the sugar
solution cools. This is similar to the
process by which molten rock cools to
form mineral crystals.
3. The sides and bottom of the pan are
the sites of formation in the salt solution.
In the sugar solution, the crystals form on
the string or sides of the test tube.
Writing Activity (p. 20)
A mineral is a naturally occurring solid that
has a definite chemical makeup and crystal
shape. Minerals contain specific combinations
of elements, which are chemically pure
substances. Minerals are identified based
on their properties, or characteristics. For
example, minerals can be identified by the
color of their outer surface. Minerals can
also be identified by their streak, which is the
color of the mark they leave when rubbed on
a piece of porcelain. Luster, or the way the
surface of a mineral reflects light, is another
property. Metallic, nonmetallic, waxy, and
earthy are some words used to describe a
mineral’s luster. A mineral’s hardness can
be determined by using Mohs hardness scale.
Cleavage refers to a mineral’s tendency
to break along flat planes. Fracture is the
tendency of minerals to break along irregular
or curved surfaces.
In Your Own Words (p. 20)
1. Minerals are found in nature and have a
definite chemical makeup and crystal shape.
2. Minerals form when molten rock on or
beneath Earth’s surface cools and when
mineral-rich water evaporates. They can also
form as a result of changes in temperature,
pressure, and chemical makeup of rocks.
3. Luster refers to the way a mineral’s surface
reflects light. Metallic, nonmetallic, waxy, and
earthy are all terms used to describe luster.
Visual Learning Company 1-800-453-8481
Mineral Identification (p. 24)
1. Answers will vary.
2. Answers will vary.
3. Density, crystal structure, magnetism, and
odor are other properties that can be used to
identify minerals.
Exploring Mono Lake (p. 25)
1. Mono Lake is two to three times saltier
than the ocean because there is no outlet
for the mineral-rich water. Fresh water
evaporates, leaving behind the minerals
and salts.
2. Tufa towers form when the lake water,
saturated with minerals and salts left
behind by evaporation, comes in contact
with fresh water.
3. Mono Lake brine shrimp, alkali flies,
and hundreds of species of migratory
birds, including the California gull, live in
and around Mono Lake. Fish are not able
to survive in the lake.
4. The water level dropped drastically
when Los Angeles began diverting water,
forcing many of the organisms living
around the lake to leave the area.
Minerals
Page
13
Pre-Test
Name
Circle the best answer for each of the following questions.
1. Rocks are made of a mixture of two or more of the following:
a. igneous
b. sedimentary
c. diamonds
d. minerals
2. Most minerals are made up of two or more chemically pure substances called:
a. rocks
b. nonsilicates
c. elements
d. silicates
3. Silicate minerals contain this element, which is very common in rocks:
a. halite
b. silicon
c. graphite
d. quartz
4. These are physical characteristics used to identify minerals:
a. properties
b. traits
c. genes
d. linkages
5. Metallic, nonmetallic, waxy, and earthy are some terms used to describe this property:
a. hardness
b. color
c. luster
d. streak
6. Scientists use this to help determine the hardness of minerals:
a. hammer
b. microscope
c. telescope
d. Mohs hardness scale
7. This refers to the tendency of quartz and other minerals to break along irregular or
curved surfaces:
a. fracture
b. cleavage
c. strata
d. shale
8. This material must cool in order for mineral crystals to form on or beneath Earth’s
surface:
a. wax
b. water
c. geysers
d. molten rock
9. The color of a mineral’s powder when rubbed against a porcelain plate is called:
a. luster
b. streak
c. pressure
d. precipitation
10. A solid made up of particles that form repeating patterns:
a. rock
b. element
c. igneous rock
d. crystal
Minerals
Visual Learning Company
Page
14
Pre-Test
Name
Write true or false next to each statement.
11.
Minerals are found in nature.
12.
Rocks are made up of a mixture of two or more minerals.
13.
Approximately twenty of 3,000 minerals make up over 90%
of all rocks.
14.
Luster is the color of a mineral’s powder when rubbed
against a piece of porcelain.
15.
Diamond is a 10 on Mohs hardness scale, which means that
it is very soft.
Write a short answer for each of the following.
16.
List three different properties used to identify minerals.
17. Differentiate between cleavage and fracture.
18.
Of what are rocks made?
19.
How do minerals form from molten rock?
20.
What is the difference between an element and a mineral?
Minerals
Visual Learning Company
Page
15
Post-Test
Name
Circle the best answer for each of the following questions.
1. This refers to the tendency of quartz and other minerals to break along irregular or
curved surfaces:
a. fracture
b. cleavage
c. strata
d. shale
2. The color of a mineral’s powder when rubbed against a porcelain plate is called:
a. luster
b. streak
c. pressure
d. precipitation
3. Scientists use this to help determine the hardness of minerals:
a. hammer
b. microscope
c. telescope
d. Mohs hardness scale
4. This material must cool in order for mineral crystals to form on or beneath Earth’s
surface:
a. wax
b. water
c. geysers
d. molten rock
5. Rocks are made of a mixture of two or more of the following:
a. igneous
b. sedimentary
c. diamonds
d. minerals
6. Silicate minerals contain this element, which is very common in rocks:
a. halite
b. silicon
c. graphite
d. quartz
7. A solid made up of particles that form repeating patterns:
a. rock
b. element
c. igneous rock
d. crystal
8. These are physical characteristics used to identify minerals:
a. properties
b. traits
c. genes
d. linkages
9. Most minerals are made up of two or more chemically pure substances called:
a. rocks
b. nonsilicates
c. elements
d. silicates
10. Metallic, nonmetallic, waxy, and earthy are some terms used to describe this property:
a. hardness
b. color
c. luster
d. streak
Minerals
Visual Learning Company
Page
16
Post-Test
Name
Write true or false next to each statement.
11.
Luster is the color of a mineral’s powder when rubbed
against a piece of porcelain.
12.
Approximately twenty of 3,000 minerals make up over 90%
of all rocks.
13.
Diamond is a 10 on Mohs hardness scale, which means that
it is very soft.
14.
Rocks are made up of a mixture of two or more minerals.
15.
Minerals are found in nature.
Write a short answer for each of the following.
16. Of what are rocks made?
17. What is the difference between an element and a mineral?
18. How do minerals form from molten rock?
19. Differentiate between cleavage and fracture.
20. List three different properties used to identify minerals.
Minerals
Visual Learning Company
Page
17
Video Review
Name
While you watch the video, answer these questions:
You Compare!
1. Which of these two minerals is gold?
You Observe!
2. Was this mineral scratched with a fingernail or with a steel knife?
You Observe!
3. Describe how this quartz breaks.
After you watch the video, test your knowledge with these
questions.
1. ___________ have a definite chemical makeup and crystal shape.
2. A ___________ is a characteristic of a mineral.
3. This mineral has a metallic ___________.
4. ___________ is the tendency of minerals to break along flat surfaces.
5. When ___________ rock cools, mineral crystals form.
Minerals
Visual Learning Company
Page
18
Vocabulary
Name
Use these words to fill in the blanks next to the sentences below.
Words
luster
properties
Mohs hardness scale
fracture
mineral
cleavage crystal
silicon
streak
element
1.
A naturally occurring solid that has a definite chemical
makeup and crystal shape.
2.
A solid made of particles that form a repeating pattern.
3.
The tendency of minerals to break along irregular or
curved surfaces.
4.
A chemically pure substance.
5.
The element in silicate minerals that is found in many
rocks.
6.
Physical characteristics used to identify minerals.
7.
The color of a mineral’s powder when rubbed against a
piece of porcelain.
8.
This describes the way a mineral’s surface reflects
light.
9.
Scientists use this to determine a mineral’s hardness.
10.
The tendency of a mineral to break along flat surfaces.
Minerals
Visual Learning Company
Page
19
Writing Activity
Words
cleavage
elements
fracture
light
Name
streak
hardness
luster
color
mineral
properties
Use the correct word from above to complete the sentences in the following
paragraph.
A __________ is a naturally occurring solid that has a definite chemical makeup
and crystal shape. Minerals contain specific combinations of __________, which
are chemically pure substances. Minerals are identified based on their
__________, or characteristics. For example, minerals can be identified by the
__________ of their outer surface. Minerals can also be identified by their
__________, which is the color of the mark they leave when rubbed on a piece
of porcelain. Luster, or the way the surface of a mineral reflects __________, is
another property. Metallic, nonmetallic, waxy, and earthy are some words used
to describe a mineral’s __________. A mineral’s __________ can be determined
by using Mohs hardness scale. __________ refers to a mineral’s tendency to
break along flat planes. __________ is the tendency of minerals to break along
irregular or curved surfaces.
In Your Own Words
1. List three characteristics of minerals.
2. Describe two ways that minerals form.
3. What is a mineral’s luster and what are common words used to describe it?
Minerals
Visual Learning Company
Page
20
Making Crystals
Name
Background: A mineral is a naturally occurring solid with a definite chemical makeup
and crystal structure. A crystal is made of particles that form a repeating pattern.
Some mineral crystals form when molten rock cools on or below Earth’s surface.
Mineral crystals can also form in mineral-rich solution or when mineral-rich water
evaporates. In this activity you will make your own crystals.
Materials:
test tube
test tube rack
sugar
salt
water
oven mitt
two glass jars
small pot
shallow glass pan
hot plate
toothpick
string
magnifying lens
aluminum foil
Activity:
1. Before you begin, draw pictures of a salt crystal and sugar crystal on the following
page. Use the magnifying lens to closely examine the crystals.
2. To create the salt solution, add salt to a glass jar that is half full of water, stirring
constantly. Continue adding the salt until it stops dissolving in the water.
3. Pour a thin layer of the salt solution into the glass pan and set aside.
4. To create the sugar solution, repeat step 2, substituting sugar for salt.
5. Your teacher will pour the sugar solution into the small pot and heat it on the hot
plate, stirring frequently. Once the solution is heated, your teacher will transfer the liquid
into the test tube, which is suspended from the test tube rack. Caution: The sugar
solution is very hot! Do not touch the test tube once the liquid has been poured
into it. If you need to touch it, make sure your hands are protected with an oven
mitt.
6. Tie one end of the string to the center of the toothpick. Place the toothpick over the
top of the test tube, allowing the string to dangle into the solution. You do not want the
string to touch the bottom or sides of the test tube, so adjust as needed.
7. Lightly cover the test tube with aluminum foil and set aside.
8. Do not touch the two solutions for one week. At the end of one week, observe
the pan and test tube. Draw pictures of the crystals formed from the salt and sugar
solutions on the following page. Use a magnifying lens if necessary.
9. Answer the questions on the following page.
Minerals
Visual Learning Company
Page
21
Making Crystals
Name
Salt crystal
Sugar crystal
Salt crystal - one week later
Sugar crystal - one week later
Questions:
1. What process caused the salt solution to form crystals? Give an example of how this
occurs in nature.
2. What process caused the sugar solution to produce crystals? Give an example of
how this occurs in nature.
3. Crystals need a site for formation. Identify the sites for the sugar and salt solutions.
Minerals
Visual Learning Company
Page
22
Mineral
Identification
Name
Background: Minerals possess a set of specific properties, or characteristics, that
can be used to help identify them. Color is one of the most obvious properties, yet
it can also be the least helpful in identifying materials. Color is often determined by
slight variations in a mineral’s chemical formula. One mineral can often come in many
different colors, and two minerals can have the same color. A mineral’s hardness
can be determined by a scratch test. Mohs scale of hardness ranks minerals from
1 (softest) to 10 (hardest). Minerals are also identified based on how they break.
Cleavage refers to a mineral’s tendency to break along flat surfaces. Fracture refers
to a mineral’s tendency to break along irregular or curved surfaces. A mineral’s streak
refers to the color powder it leaves when rubbed against a piece of porcelain. Minerals
can also be identified based on their luster, which is the way the surface of a mineral
reflects light. Metallic, nonmetallic, waxy, earthy, glossy, and dull are common terms
used to describe luster. These are just a few examples of properties that can be used to
identify minerals.
Materials:
5 numbered samples of unknown minerals
copper penny
glass square
steel file or nail
porcelain streak plate
magnifying lens
mineral identification key
Activity:
Record your observations in the chart on the following page.
1. Identify the color and luster of each mineral.
2. Rub each mineral against the streak plate and record the color of the streak.
3. Use a penny, glass square, steel nail or file, and your fingernail to try to scratch
the mineral. Refer to the table on the following page to determine the approximate
hardness of the mineral.
4. Observe the surface of each mineral to determine if it displays cleavage or fracture.
5. Your teacher will provide you with the names and descriptions of the unknown
minerals, but will not indicate to which sample they belong. Match your unknown
samples with the correct mineral name and description.
Minerals
Visual Learning Company
Page
23
Mineral
Identification
Name
The following table, based on Mohs scale of hardness, can be used to approximate
a mineral’s hardness:
Material
Hardness
fingernail
2.5
coin
3.5
glass
5.5
steel knife
6.5
*For example, if a mineral can be scratched by a coin, but not a piece of glass, it has a
hardness between 3.5 and 5.5.
Sample #
Color and
luster
Hardness
Cleavage or
fracture
Streak
Mineral
name
Questions:
1. Which property do you feel was the most helpful in identifying the minerals?
Why?
2. Which property do you feel was the least helpful in identifying the minerals?
Why?
3. What other properties do you think could be helpful in identifying minerals?
Minerals
Visual Learning Company
Page
24
Exploring
Mono Lake
Name
Activity: Read the information below and answer the questions that follow.
Mono Lake is a large, ancient lake located in the Great Basin Desert in eastern California,
near the Nevada border. It covers about 60 square miles (155 km2) and is 13 miles (20.9 km)
wide by 8 miles (12.9 km) long. It is believed to be about 760,000 years old, making it one of
the oldest lakes in North America. It is a closed hydrological basin, which means that water
flows in, but does not flow out. Since its formation, minerals and salts from the surrounding
area have been carried into the lake by rivers and streams that feed into it. Fresh water is
able to leave the lake via evaporation, which is the process through which water becomes gas.
However, the minerals and salts do not evaporate, causing them to remain in the lake. As a
result, the lake is two to three times as salty as seawater. The mineral-rich water is denser
than ocean water and will help you float if you swim in it!
One of the most remarkable features of Mono Lake are its tufa towers. Tufa is a type of
limestone rock, which contains the mineral calcite. Some of the tufa towers located around
the lake are estimated to be between 200 and 900 years old. Tufa towers form when
freshwater comes in contact with the salty water of Mono Lake. The towers form underwater
at the mouth of the streams. They become visible as lake water evaporates and the lake level
drops. Some tufa towers, as old as 13,000 years, are located beyond the current edges of the
lake, illustrating the outer boundaries of the lake.
Due to the high salinity of the water, there are no fish native to the lake and efforts to introduce
fish have failed. However, the lake is home to trillions of Mono Lake brine shrimp, which are
tiny shrimp that exist nowhere else in the world. They offer no nutritional value to people,
but do feed the birds that inhabit the area. The lake is also inhabited by alkali flies, which, in
addition to the brine shrimp, attract approximately 100 species of migratory birds to the area.
Mono Lake has the second largest population of California gulls, with over 44,000 to 65,000
living at the lake periodically throughout the year.
In the early 1940s, the fast-growing city of Los Angeles needed more water than was available
in southern California. In search of water, the city turned to Mono Lake and began diverting
water that naturally fed into the lake. This caused the lake level to drop quickly. Soon more
water was evaporating than entering the lake, causing the lake level to drop drastically. This
forced many animals to leave the area. In the 1970s, the Mono Lake Committee and the
Audubon Society filed a famous law suit to protect the lake, and in 1994 the California State
Water Resources Control Board granted the lake special protections. Since that time, the lake
level has risen slowly.
Questions:
1. What makes the water of Mono Lake unique? Why is it this way?
2. How do tufa towers form?
3. What organisms live in and around Mono Lake? What organisms are not able to survive?
4. What happened to Mono Lake when Los Angeles began diverting water?
Minerals
Visual Learning Company
Page
25