You Rock!
© 2009 Barbara J. Shaw Ph.D., Science A to Z
Permission is granted to make and distribute copies of this lesson plan for educational use only.
http://en.wikipedia.org/wiki/Geologic_time
http://www.fas.org/irp/imint/docs/rst/Sect2/Sect2_1b.html
http://pubs.usgs.gov/gip/fossils/rocks-layers.html
http://pubs.usgs.gov/gip/dynamic/understanding.html
http://en.wikipedia.org/wiki/Rock_cycle
http://explorations.ucsd.edu/Voyager/Activities/images/playdoh.gif
http://en.wikipedia.org/wiki/Alfred_wegner
http://scotese.com - specifically: http://scotese.com/newpage5.htm
http://www.math.montana.edu/~nmp/materials/ess/geosphere/inter/activities/plate_calc/pangaea_map.gif
http://www.pbs4549.org/antarcti/platetec.htm
http://chemistry.about.com/od/growingcrystals/Growing_Crystals.htm
http://earthsci.org/mineral/rockmin/mineral/mineral_i_d.html
Background:
Uniformitarianism is the assumption that the natural processes operating in the past are the same
as those that can be observed operating in the present. "The present is the key to the past."
Catastrophism is the idea that Earth has been affected by sudden, short-lived, violent events that
were sometimes worldwide in scope.
Various geologists in the 1700-1800s began to publish descriptions of the sequences they
studied. As the Geologic Column grew, estimates of their ages were made using mainly
deposition rates. Individual sequences within the column were assigned times in the past which
resulted from the column estimates. It became conventional to give a name to a sequence that
seemed to represent a long span of time but with certain diagnostic properties (e.g., a collection
of life forms that, while evolving, possessed similarities). These sequences became Periods in a
temporal-stratigraphic nomenclature and all rocks contained within the sequence made up a
System. Subdivision of Periods into
smaller time spans yielded Epochs,
with their Rocks being Series. Broader
divisions of time made up some
number of Periods (each younger one
overlying an older Period - Law of
Superposition) were called Eras.
Geologists and other scientists use the
geological time scale to describe the
timing and relationships between
events that have occurred during the
history of Earth. The table of geologic
periods presented here agrees with the
dates and nomenclature proposed by
the International Commission on
Stratigraphy, and uses the standard
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color codes of the United States Geological Survey.
Evidence from radiometric dating indicates that the Earth is about 4.570 billion years old. The
geological or deep time of Earth's past has been organized into various units according to events
that took place in each period. Different spans of time on the time scale are usually delimited by
major geological or paleontological events, such as mass extinctions. For example, the
boundary between the Cretaceous period and the Paleogene period is defined by the extinction
event, known as the Cretaceous–Tertiary extinction event, that marked the demise of the
dinosaurs and of many marine species. Older periods that predate the reliable fossil record are
defined by absolute age.
We study Earth's history by studying the record of past events that is preserved in the rocks. The
layers of the rocks are the pages in our history book.
Most of the rocks exposed at the surface of Earth are sedimentary--formed from particles of
older rocks that have been broken apart by water or wind. The gravel, sand, and mud settle to the
bottom in rivers, lakes, and oceans. These sedimentary particles may bury living and dead
animals and plants on the lake or sea bottom. With the passage of time and the accumulation of
more particles, and often with chemical changes, the sediments at the bottom of the pile become
rock. Gravel becomes a rock called conglomerate, sand becomes sandstone, mud becomes
mudstone or shale, and the animal skeletons and plant pieces can become fossils.
An idealized
view of a
modern
landscape
with some
plants and
animals that
could be
preserved as
fossils.
As early as the mid-1600's, the Danish scientist Nicholas Steno studied the relative positions of
sedimentary rocks. He found that solid particles settle from a fluid according to their relative
weight or size. The largest, or heaviest, settle first, and the smallest, or lightest, settle last. Slight
changes in particle size or composition result in the
formation of layers, also called beds, in the rock.
Layering, or bedding, is the most obvious feature of
sedimentary rocks.
Originations of major life forms
Sedimentary rocks are formed particle by particle
and bed by bed, and the layers are piled one on top
of the other. Thus, in any sequence of layered rocks,
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a given bed must be older than any bed on top of it. This Law of Superposition is fundamental to
the interpretation of Earth history, because at any one location it indicates the relative ages of
rock layers and the fossils in them.
Layered rocks form when particles settle from water or air. Steno's Law of Original Horizontality
states that most sediments, when originally formed, were laid down horizontally. However, many
layered rocks are no longer horizontal. Because of the Law of Original Horizontality, we know
that sedimentary rocks that are not horizontal either were formed in special ways or, more often,
were moved from their horizontal position by later events, such as tilting during episodes of
mountain building.
Rock layers are also called strata (the plural form of the Latin word stratum), and stratigraphy is
the science of strata. Stratigraphy deals with all the characteristics of layered rocks; it includes
the study of how these rocks relate to time.
Scientists now have a fairly good understanding of how the plates move and how such
movements relate to earthquake activity. Most movement occurs along narrow zones between
plates where the results of plate-tectonic forces are most evident.
There are four types of plate boundaries:
 Divergent boundaries -- where new crust is generated as the plates pull away from each
other.



Convergent boundaries -- where crust is destroyed as one plate dives under another.
Transform boundaries -- where crust is neither produced nor destroyed as the plates slide
horizontally past each other.
Plate boundary zones -- broad belts in which boundaries are not well defined and the
effects of plate interaction are unclear.
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Divergent boundaries:
Divergent boundaries occur along spreading centers where plates are moving apart and new crust
is created by magma pushing up from the mantle. Picture two giant conveyor belts, facing each
other but slowly moving in opposite directions as they transport newly formed oceanic crust
away from the ridge crest.
Perhaps the best known of the divergent boundaries is the Mid-Atlantic Ridge. This submerged
mountain range, which extends from the Arctic Ocean to beyond the southern tip of Africa, is but
one segment of the global mid-ocean ridge system that encircles the Earth. The rate of spreading
along the Mid-Atlantic Ridge averages about 2.5 centimeters per year (cm/yr), or 25 km in a
million years. This rate may seem slow by human standards, but because this process has been
going on for millions of years, it has resulted in plate movement of thousands of kilometers.
Seafloor spreading over the past 100 to 200 million years has caused the Atlantic Ocean to grow
from a tiny inlet of water between the continents of Europe, Africa, and the Americas into the
vast ocean that exists today.
The volcanic country of Iceland, which straddles the Mid-Atlantic Ridge, offers scientists a
natural laboratory for studying on land the processes also occurring along the submerged parts of
a spreading ridge. Iceland is splitting along the spreading center between the North American
and Eurasian Plates, as North America moves westward relative to Eurasia.
The consequences of plate movement are easy to see around Krafla Volcano, in the northeastern
part of Iceland. Here, existing ground cracks have widened and new ones appear every few
months. From 1975 to 1984, numerous episodes of rifting (surface cracking) took place along the
Krafla fissure zone. Some of these rifting events were accompanied by volcanic activity; the
ground would gradually rise 1-2 m before abruptly dropping, signalling an impending eruption.
Between 1975 and 1984, the displacements caused by rifting totalled about 7 m.
East Africa may be the site of the Earth's next major ocean. Plate interactions in the region
provide scientists an opportunity to study first hand how the Atlantic may have begun to form
about 200 million years ago. Geologists believe that, if spreading continues, the three plates that
meet at the edge of the present-day African continent will separate completely, allowing the
Indian Ocean to flood the area and making the easternmost corner of Africa (the Horn of Africa)
a large island.
Convergent boundaries:
The size of the Earth has not changed significantly during the past 600 million years, and very
likely not since shortly after its formation 4.6 billion years ago. The Earth's unchanging size
implies that the crust must be destroyed at about the same rate as it is being created, as Harry
Hess surmised. Such destruction (recycling) of crust takes place along convergent boundaries
where plates are moving toward each other, and sometimes one plate sinks (is subducted) under
another. The location where sinking of a plate occurs is called a subduction zone.
The type of convergence -- called by some a very slow "collision" -- that takes place between
plates depends on the kind of lithosphere involved. Convergence can occur between an oceanic
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and a largely continental plate, or between two largely oceanic plates, or between two largely
continental plates.
If by magic we could pull a plug and drain the Pacific Ocean, we would see a most amazing sight
-- a number of long narrow, curving trenches thousands of kilometers long and 8 to 10 km deep
cutting into the ocean floor. Trenches are the deepest parts of the ocean floor and are created by
subduction.
Off the coast of South America along the Peru-Chile trench, the oceanic Nazca Plate is pushing
into and being subducted under the continental part of the South American Plate. In turn, the
overriding South American Plate is being lifted up, creating the towering Andes mountains, the
backbone of the continent. Strong, destructive earthquakes and the rapid uplift of mountain
ranges are common in this region. Even though the Nazca Plate as a whole is sinking smoothly
and continuously into the trench, the deepest part of the subducting plate breaks into smaller
pieces that become locked in place for long periods of time before suddenly moving to generate
large earthquakes. Such earthquakes are often accompanied by uplift of the land by as much as a
few meters.
On 9 June 1994, a magnitude-8.3 earthquake struck about 320 km northeast of La Paz, Bolivia,
at a depth of 636 km. This earthquake, within the subduction zone between the Nazca Plate and
the South American Plate, was one of deepest and largest subduction earthquakes recorded in
South America. Fortunately, even though this powerful earthquake was felt as far away as
Minnesota and Toronto, Canada, it caused no major damage because of its great depth.
Oceanic-continental convergence also sustains many of the Earth's active volcanoes, such as
those in the Andes and the Cascade Range in the Pacific Northwest. The eruptive activity is
clearly associated with subduction, but scientists vigorously debate the possible sources of
magma: Is magma generated by the partial melting of the subducted oceanic slab, or the
overlying continental lithosphere, or both?
As with oceanic-continental convergence, when two oceanic plates converge, one is usually
subducted under the other, and in the process a trench is formed. The Marianas Trench
(paralleling the Mariana Islands), for example, marks where the fast-moving Pacific Plate
converges against the slower moving Philippine Plate. The Challenger Deep, at the southern end
of the Marianas Trench, plunges deeper into the Earth's interior (nearly 11,000 m) than Mount
Everest, the world's tallest mountain, rises above sea level (about 8,854 m).
Subduction processes in oceanic-oceanic plate convergence also result in the formation of
volcanoes. Over millions of years, the erupted lava and volcanic debris pile up on the ocean floor
until a submarine volcano rises above sea level to form an island volcano. Such volcanoes are
typically strung out in chains called island arcs. As the name implies, volcanic island arcs, which
closely parallel the trenches, are generally curved. The trenches are the key to understanding how
island arcs such as the Marianas and the Aleutian Islands have formed and why they experience
numerous strong earthquakes. Magmas that form island arcs are produced by the partial melting
of the descending plate and/or the overlying oceanic lithosphere. The descending plate also
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provides a source of stress as the two plates interact, leading to frequent moderate to strong
earthquakes.
The Himalayan mountain range dramatically demonstrates one of the most visible and
spectacular consequences of plate tectonics. When two continents meet head-on, neither is
subducted because the continental rocks are relatively light and, like two colliding icebergs,
resist downward motion. Instead, the crust tends to buckle and be pushed upward or sideways.
The collision of India into Asia 50 million years ago caused the Eurasian Plate to crumple up and
override the Indian Plate. After the collision, the slow continuous convergence of the two plates
over millions of years pushed up the Himalayas and the Tibetan Plateau to their present heights.
Most of this growth occurred during the past 10 million years. The Himalayas, towering as high
as 8,854 m above sea level, form the highest continental mountains in the world. Moreover, the
neighboring Tibetan Plateau, at an average elevation of about 4,600 m, is higher than all the
peaks in the Alps except for Mont Blanc and Monte Rosa, and is well above the summits of most
mountains in the United States.
Transform boundaries:
The zone between two plates sliding horizontally past one another is called a transform-fault
boundary, or simply a transform boundary. The concept of transform faults originated with
Canadian geophysicist J. Tuzo Wilson, who proposed that these large faults or fracture zones
connect two spreading centers (divergent plate boundaries) or, less commonly, trenches
(convergent plate boundaries). Most transform faults are found on the ocean floor. They
commonly offset the active spreading ridges, producing zig-zag plate margins, and are generally
defined by shallow earthquakes. However, a few occur on land, for example the San Andreas
fault zone in California. This transform fault connects the East Pacific Rise, a divergent
boundary to the south, with the South Gorda -- Juan de Fuca -- Explorer Ridge, another divergent
boundary to the north.
The San Andreas fault zone, which is about 1,300 km long and in places tens of kilometers wide,
slices through two thirds of the length of California. Along it, the Pacific Plate has been grinding
horizontally past the North American Plate for 10 million years, at an average rate of about 5
cm/yr. Land on the west side of the fault zone (on the Pacific Plate) is moving in a northwesterly
direction relative to the land on the east side of the fault zone (on the North American Plate).
Oceanic fracture zones are ocean-floor valleys that horizontally offset spreading ridges; some of
these zones are hundreds to thousands of kilometers long and as much as 8 km deep. Examples
of these large scars include the Clarion, Molokai, and Pioneer fracture zones in the Northeast
Pacific off the coast of California and Mexico. These zones are presently inactive, but the offsets
of the patterns of magnetic striping provide evidence of their previous transform-fault activity.
Not all plate boundaries are as simple as the main types discussed above. In some regions, the
boundaries are not well defined because the plate-movement deformation occurring there
extends over a broad belt (called a plate-boundary zone). One of these zones marks the
Mediterranean-Alpine region between the Eurasian and African Plates, within which several
smaller fragments of plates (microplates) have been recognized. Because plate-boundary zones
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involve at least two large plates and one or more microplates caught up between them, they tend
to have complicated geological structures and earthquake patterns.
We can measure how fast tectonic plates are moving today, but how do scientists know what the
rates of plate movement have been over geologic time? The oceans hold one of the key pieces to
the puzzle. Because the ocean-floor magnetic striping records the flip-flops in the Earth's
magnetic field, scientists, knowing the approximate duration of the reversal, can calculate the
average rate of plate movement during a given time span. These average rates of plate
separations can range widely. The Arctic Ridge has the slowest rate (less than 2.5 cm/yr), and the
East Pacific Rise near Easter Island, in the South Pacific about 3,400 km west of Chile, has the
fastest rate (more than 15 cm/yr).
Evidence of past rates of plate movement also can be obtained from geologic mapping studies. If
a rock formation of known age -- with distinctive composition, structure, or fossils -- mapped on
one side of a plate boundary can be matched with the same formation on the other side of the
boundary, then measuring the distance that the formation has been offset can give an estimate of
the average rate of plate motion. This simple but effective technique has been used to determine
the rates of plate motion at divergent boundaries, for example the Mid-Atlantic Ridge, and
transform boundaries, such as the San Andreas Fault.
Current plate movement can be tracked directly by means of ground-based or space-based
geodetic measurements; geodesy is the science of the size and shape of the Earth. Ground-based
measurements are taken with conventional but very precise ground-surveying techniques, using
laser-electronic instruments. However, because plate motions are global in scale, they are best
measured by satellite-based methods. The late 1970s witnessed the rapid growth of space
geodesy, a term applied to space-based techniques for taking precise, repeated measurements of
carefully chosen points on the Earth's surface separated by hundreds to thousands of kilometers.
The three most commonly used space-geodetic techniques -- very long baseline interferometry
(VLBI), satellite laser ranging (SLR), and the Global Positioning System (GPS) -- are based on
technologies developed for military and aerospace research, notably radio astronomy and
satellite tracking.
Among the three techniques, to date the GPS has been the most useful for studying the Earth's
crustal movements. Twenty-one satellites are currently in orbit 20,000 km above the Earth as
part of the NavStar system of the U.S. Department of Defense. These satellites continuously
transmit radio signals back to Earth. To determine its precise position on Earth (longitude,
latitude, elevation), each GPS ground site must simultaneously receive signals from at least four
satellites, recording the exact time and location of each satellite when its signal was received. By
repeatedly measuring distances between specific points, geologists can determine if there has
been active movement along faults or between plates. The separations between GPS sites are
already being measured regularly around the Pacific basin. By monitoring the interaction
between the Pacific Plate and the surrounding, largely continental plates, scientists hope to learn
more about the events building up to earthquakes and volcanic eruptions in the circum-Pacific
Ring of Fire. Space-geodetic data have already confirmed that the rates and direction of plate
movement, averaged over several years, compare well with rates and direction of plate
movement averaged over millions of years.
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The rock cycle is a fundamental concept in geology that describes the dynamic transitions
through geologic time among the three main rock types: sedimentary, metamorphic, and igneous.
Each type of rock is altered or destroyed when it is forced out of its equilibrium conditions. An
igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or
melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate
tectonics and the water cycle, rocks do not remain in equilibrium and are forced to change as
they encounter new environments. The rock cycle is an illustration that explains how the 3 rock
types are related to each other and how processes change from one type to another over time.
The original concept of the rock cycle is usually attributed to James Hutton, the eighteenth
century father of geology. The rock cycle was a part of Hutton's uniformitarianism and his
famous quote: no vestige of a beginning, and no prospect of an end, applied in particular to the
rock cycle and the envisioned cyclical nature of geologic processes. This concept of a repetitive
non-evolutionary rock cycle remained dominant until the plate tectonics revolution of the 1960s.
With the developing understanding of the driving engine of plate tectonics, the rock cycle
changed from endlessly repetitive to a gradually evolving process. The Wilson cycle (a plate
tectonics based rock cycle) was developed by J. Tuzo Wilson during the 1960s and 70s.
When rocks are pushed deep under the Earth's surface, they may melt into magma. If the
conditions no longer exist for the magma to stay in its liquid state, it will cool and solidify into
an igneous rock. A rock that cools within the Earth is called intrusive or plutonic and will cool
very slowly, producing a coarse-grained texture. As a result of volcanic activity, magma (which
is called Lava when it reaches Earth's surface) may cool very rapidly while being on Earth's
surface exposed to the atmosphere and are called extrusive or volcanic rocks. These rocks are
fine-grained and sometimes cool so rapidly that no crystals can form and result in a natural glass,
such as obsidian. Any of the three main types of rocks (Igneous, Sedimentary, and Metamorphic
rocks) can melt into magma and cool into igneous rocks.
Rock masses of igneous origin have no sooner cooled than they begin to change. The solids with
which the magma is charged are slowly dissipated, lava flows often remain hot and steaming for
many years. These gases attack the components of the rock and deposit new minerals in cavities
and fissures. The zeolites are largely of this origin. Even before these "post-volcanic" processes
have ceased, atmospheric decomposition or weathering begins as the mineral components of
volcanic and igneous rocks are not stable under surface atmospheric conditions. Rain, frost,
carbonic acid, oxygen and other agents operate continuously, and do not cease until the whole
mass has crumbled down and most of its ingredients have been resolved into new products or
carried away in aqueous solution. In the classification of rocks these secondary changes are
generally considered unessential: rocks are classified and described as if they were ideally fresh,
though this is rarely the case in nature.
Epigenitic change (secondary processes) may be arranged under a number of headings, each of
which is typical of a group of rocks or rock-forming minerals, though usually more than one of
these alterations will be found in progress in the same rock. Silicification, the replacement of the
minerals by crystalline or crypto-crystalline silica, is most common in felsic rocks, such as
rhyolite, but is also found in serpentine, etc. Kaolinization is the decomposition of the feldspars,
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which are the most common minerals in igneous rocks, into kaolin (along with quartz and other
clay minerals); it is best shown by granites and syenites. Serpentinization is the alteration of
olivine to serpentine (with magnetite); it is typical of peridotites, but occurs in most of the mafic
rocks. In uralitization secondary hornblende replaces augite; this occurs very generally in
diabases; chloritization is the alteration of augite (biotite or hornblende) to chlorite, and is seen in
many diabases, diorites and greenstones. Epidotization occurs also in rocks of this group, and
consists in the development of epidote from biotite, hornblende, augite or plagioclase feldspar.
Rocks exposed to high temperatures and/or pressures can be changed physically or chemically to
form a different rock, called metamorphic. Regional metamorphism refers to the effects on large
masses of rocks over a wide area, typically associated with mountain building events within
orogenic belts. These rocks commonly exhibit distinct bands of differing mineralogy and colors,
called foliation. Another main type of metamorphism is caused when a body of rock comes into
contact with an igneous intrusion that heats up this surrounding country rock. This contact
metamorphism results in a rock that is altered and re-crystallized by the extreme heat of the
magma and/or by the addition of fluids from the magma that add chemicals to the surrounding
rock (metasomatism). Any pre-existing type of rock can be modified by the processes of
metamorphism.
Rocks exposed to the atmosphere are variably unstable and subject to the processes of
weathering and erosion. Weathering and erosion breaks the original rock down into smaller
fragments and carries away dissolved material. This fragmented material accumulates and is
buried by additional material. While an individual grain of sand is still a member of the class of
rock it was formed from, a rock made up of such grains fused together is sedimentary.
Sedimentary rocks can be formed from the lithification of these buried smaller fragments (clastic
sedimentary rock), the accumulation and lithification of material generated by living organisms
(biogenic sedimentary rock - fossils), or lithification of chemically precipitated material from a
mineral bearing solution due to evaporation (precipitate sedimentary rock). Clastic rocks can be
formed from fragments broken apart from larger rocks of any type, due to processes such as
erosion or from organic material, like plant remains. Biogenic and precipitate rocks form from
the deposition of minerals from chemicals dissolved from all other rock types.
Procedure:
This unit is a three-week introduction to geology, covering the major concepts in this science.
Each lesson is designed for 45 minutes covering:
 Geologic Concepts:
o Geologic Time
 Uniformitarianism vs. Catastrophism
 Superposition
 Fossils
o Earth’s Interior
 Plate Tectonics
 Plate Boundaries
o Minerals and Matter
 Rock Cycle
 Igneous Rock
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

 Volcanos
Sedimentary Rock
 Weathering
Metamorphic Rock
 Metamorphism
Week 1
#1 Introduction to Geology:
 What do I know
 What do I want to learn
Week 2
#6 Plate Tectonics
 Students solve the puzzle of
Pangaea
Tuesday
#2 Geologic Time:
 Students transform number of
years into millimeters, and walk
back to the formation of the earth
Wednesday
#3 Superposition
 Students construct a model of the
layers of sediment to demonstrate
superposition
#4 Fossils
 Students research, draw, and place
their fossils on the Geologic Time
Line from lesson #2.
#7 Plate Boundaries
 Students model the different types
of plate boundaries, convergent,
divergent, and transform
boundaries
#8 Rock Cycle
 Students model the rock cycle
Monday
Thursday
Friday
#5 Model of the Earth
 Students construct a model of the
Earth and it’s layers
#9 Minerals and Matter
 Students grow their own minerals
and apply the mineral definitions
to their results
#10 Igneous, Sedimentary,
Metamorphic Rocks
 Students conduct tests on rock to
group according to different traits
Week 3
#11 Follow-up: What I want to know. Students explore in depths one of the questions they
asked during this two-week unit using the scientific method (all or part).
One week prior to starting this unit, divide the students into groups of 5. Ask students to divide
the list of organism (on page 17) so that they each are responsible for 4 of them. Assign the
students to research their organisms, and be prepared for lesson 4 with their information.
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Lesson 1: Introduction to Geology
Materials (1 set for class):
 Butcher paper ~ 4’ x 5’
 Permanent markers (variety of colors)
Preparation:
 Gather materials
 Divide butcher paper into 2 columns. Title the first column, “What we know,” and the
second column, “What we want to learn.”
Directions:
 Ask students, “What do you know about Geology? What do you know about our planet
Earth?” Write down answers on butcher paper to keep through this unit.
 Record responses in the first column of the butcher paper. Ask students to expand on this
information. Differentiate between information students “know” from information that
they think they know.
 Optional, have a 3rd column (between “What we know,” and “What we want to learn.”)
titled “What we think we know.”
Lesson 2: Geologic Timeline
Materials (1 set per team of students):
 15’ strip of butcher paper
 markers (in variety of colors)
 meter sticks
 rulers
 Copy of geologic time scale (page 3)
Preparation:
 Gather materials
 Cut butcher paper into 15 feet strips, one per student team
Directions:
Divide students into groups of 5
How long is 4.6 billion years?
4.6 billion = 4,600,000,000.
That is a HUGE number! Just how big is it really? Today, we are going to create a timeline, to
make a model of years by converting one million years to one millimeter. (1,000,000 years =
1mm) How big is one millimeter? Look at your ruler. If you look carefully between the 0 and 1
centimeter (cm), you can see 10 lines. Each space between those lines is approximately 1
millimeter.
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We are going to measure 4 Eons (very long times) Eras (The Phanerozoic Eon is divided into 3
Eras), and then we are going to measure Periods (with a total of 11).
The Phanerozoic (use a green marker):
Write down time ending:
545
Subtract the time starting:
0
How long is your line?
545 mm
There are three Eons in the Precambrian that are not shown. They are:
Proterozoic (use a red marker):
Write down time ending:
2,500
Subtract the time starting:
545
How long is your line?
1,955 mm
Archean (use a blue marker):
Write down time ending:
3,800
Subtract the time starting:
2,500
How long is your line?
1,300 mm
Hadean (use a black marker):
Write down time ending:
4,500
Subtract the time starting:
3,800
How long is your line?
700 mm
Measure each Eon and draw (with the color
marker indicated above) a line across the tape,
label each section of tape (with the color marker
indicated above name with the proper Eon.
Phanerozoic
Proterozoic
Archean
Hadean
Next, you need to mark off the Eras that are in the Phanerozoic. This time, you do the math to
figure out how big each era will be:
Cenozoic:
Write down time ending:
Subtract the time starting: ____
How long is your line (in mm)?
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Mesozoic:
Write down time ending:
Subtract the time starting: ____
How long is your line (in mm)?
Paleozoic:
Write down time ending:
Subtract the time starting:
__
How long is your line (in mm)?
Measure each Eon and draw (with the color marker indicated above) a line across the tape, label
each section of tape (with the color marker indicated above name with the proper Eon.
Finally, you need to mark off the Periods that are in the Paleozoic, Mesozoic and Cenozoic.
They are (from the top of the paper down):
Cenozoic
 Today (at the very top of the chart)
 Quaternary 1.8mm
 Tertiary 63.2mm
Mesozoic
 Cretaceous 144 – 65 = 79mm
 Jurassic 206 –144 = 62mm
 Triassic 248 – 206 = 42mm
Paleozoic
 Permian 299 – 248 = 51mm
 Carboniferous 359 – 299 = 60mm
 Devonian 416 – 359 = 57mm
 Silurian 444 – 416 = 28mm
 Ordovician 488 – 444 = 44mm
 Cambrian 542 – 488 = 54mm
Keep Geologic Time Scales for lesson 4.
Lesson 3: Stratigraphy
Materials (1 per student):
 Paper cup – 8 oz
 Large, transparent, plastic straw (Burgerville has the perfect straws)
 Homemade of playdoh in 4 different colors (yellow, green, red, blue; recipe for 28
students follows)
o 7 c. flour
o 7 c. boiling water
o 14 tbsp. cream of tartar
13
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
o 3½c. salt
o 7 tbsp. oil
o Red food coloring
o Mix and kneed all ingredients until smooth consistency
o Repeat for the other three colors (green, blue and yellow)
o Store each color separately in gallon zip-lock baggies
“Fossil” (use can use just about anything small item to represent the fossil for example a
button or stone)
Optional wax paper or newspaper to confine the mess
Preparation:
 Gather materials
 Make 7 cups of each color of homemade playdoh (each student receives ¼ cup of each
color
Directions:
 Discuss with the students Steno’s Law of Original Horizontality and the Law of
Superposition.
 Ask each student to collect 1 cup, 1 straw, ¼ cup of each color of playdoh and 1 fossil.
 Direct the students to place the blue playdoh into their cup, and press it firmly so that
there are no air bubbles. Direct the student to press the yellow playdoh firmly into their
cup on top of the blue playdoh. Direct the students to place their fossil in the red
playdoh, and to place the red playdoh into their cup on top of the yellow playdoh.
Finally, direct the students to put the green playdoh on top of the red playdoh.
 Which is the playdoh that is the oldest – the one first placed into the cup (blue)? Where
is it located (on the bottom)?
 Which is the playdoh that is the youngest – the last one placed into the cup (green)?
Where is it located (on the top)? Which playdoh is older, the yellow or the red?
 Ask if the students can see their fossil.
 Ask the students to take their straw to collect a core sample of their playdoh Earth. In
order to collect their sample, they need to carefully twist their straw back and forth with a
thumb and forefinger as
pushing slowly down.
Direct them to place their
cup on their desk and
hold it with their nondominant hand. Direct
them to CAREFULLY
stab their playdoh.
Remove the straw. Inside
the straw should be a core
of playdoh Earth (maybe
with all 4 layers).
 Ask the students to rip their cups from the playdoh, being careful not to damage their
playdoh. Ask the students to compare their core to the actual layers that were in the cup.
14


They will now simulate weathering. Ask half of the students to carefully scrape the green
playdoh, as weathering occurs at the surface, working their way to the red play doh until
their fossil begins to appear. Ask the other half of the students to break their playdoh in
half, through all 4 colors simulating faults in the Earth.
Ask the students if they can see their fossil. Not all students will be able to see it.
Discuss that fossils are found by seeing them. It isn’t until the Earth around them erodes,
or geologic action (like faulting) brings them to the surface, and then weathers them out.
Lesson 4: Fossils
Please note: The 45-minute allocated time does not include the research portion of this lesson,
which is to be assigned as homework starting 5 days prior to this lesson.
Materials (1 set per team of students):
 Organisms for Geologic Time copy (found below)
 20 Index cards
 Color pencils
 Markers
 Computers or library books
 String, yarn, or ribbon
 Clear tape
 If available, fossils of as many of the species listed. If you live close to a university, you
may be able to borrow some of these, or a rock shop may be willing to visit your
classroom and bring in some of their fossils to show the students.
Preparation:
 Gather materials
Directions:
 Divide students back into their groups of 4-5 from the geologic time line lesson.
 One week prior to this lesson, students select either 4 of the organisms listed on the
provided handout below. The students research (either with the internet or library books)
what these animals looked like, and an interesting fact or two about them as homework.
 The students sketch a picture of their organisms on one side of the index card, and on the
other side, they write some of the interesting facts they learned about their organisms.
 Each student tapes a string, ribbon or yarn on their index card, and attaches the card to
the timeline when this organism first appeared in the fossil record.
 Using a different color marker for each type of organism, the student draws a line from
the first evidence to when they went extinct or all the way to "today" (the top edge of
their timeline) if they are still around.
 Using the time line on the first page, find out when the first fossils for each of these
organisms was found. Then draw a line along the length of your paper from first fossil to
either today, or when the animal went extinct.
15
Organisms for the Geologic Timeline
Organism
bivalves (clams)
First fossils
Cambrian
Extant/Extinct Notes
Still alive
greatly increased
brachiopods
Ordovician
Still alive
crinoid
Early Ordovician
Still alive
most common fossil, now greatly
reduced
only live in deep marine water now
gastropods (snails)
Cambrian
Still alive
greatly increased
horn coral
Ordovician
Late Permian
sand dollars
Ordovician
Still alive
sea urchins
Ordovician
Still alive
tabulate coral
Late Cambrian
Late Permian
trilobites
Early Cambrian
Late Permian
first metazoan with eyes
ammonite
Devonian
Cretaceous
related to octopus, squid and
nautilus
mammal
Jurassic
Still alive
amphibian
Devonian
Still alive
reptile
Carboniferous
Still alive
bird
Jurassic
Still alive
mammal-like
reptile
Carboniferous
Triassic
insects
Devonian
Still alive
arachnid
Silurian
Still alive
dinosaur
Triassic
Cretaceous
shark
Devonian
Still alive
fish
Cambrian
Still alive
First fossils had 7 or 8 digits
(fingers or toes)!
Reptiles – currently changing to
include birds
Included in reptiles
Almost wiped out in Permian
extinction, but were dominant
animal during Permian
Mass extinctions do not seem to
impact insects
First terrestrial animal know –
scorpion fossil
Dominant animal during most of
the Mesozoic
Jawless fish, most closely related to
lampreys and hagfish
16
Lesson 5: Layers of the Earth
Materials (1 per student):
 1 handout per student
 markers
 scissors
 construction paper
 drawing compass
 ruler
 glue
Preparation:
 Gather materials
Directions:
 Discuss that the Earth is comprised of different layers. What we see as our landscape is
thinner than the skin on an apple.
 Post the measurements of the Earth layers on the blackboard, overhead, or on a piece of
butcher paper.
 Ask the students what they could do to convert this information into a scale model of the
Earth’s layers.
 Distribute the markers, construction paper, scissors, drawing compasses, and rulers to the
students.
Post the following information
The diameter of the Earth is 12,756 km.
Layer
Thick
Model
Crust
0-35 km 8½” circle
Mantle
2,890 km 8” circle
Outer Core
2,210 km 5½” circle
Inner Core
2,440 km 2½” circle
Notes
o Using the colored construction paper, have each student model the layers of the
earth. With the blue sheet, students should measure an 8½" circle for the crust and
label it 6-40 miles. The crust is made of many plates that "float" above mantle.
The crust is thicker and lighter at the continents and thinner and denser at the
ocean floor.
o The brown sheet of construction paper should be used to measure an 8" circle for
the mantle and labeled 1,800 miles. The mantle lies below the crust and is a thick
layer of solid rock. Many scientists believe that the mantle transfers heat from the
core to the surface.
o With the yellow sheet, ask students to measure a 6" circle and label it 1,375 miles.
This represents the outer core that is made of melted iron and nickel. It is much
denser than the rock layers above it. The temperature of the outer core can range
from 4000 to 9000 deg F.
17
o Use the black construction paper to represent the inner core. Students should
measure a 3" diameter circle and label it 1, 750 miles. The inner core is made of
solid iron and nickel. These materials sank to the center of the earth while it was
still in molten form.
 Ask the student to calculate the radius of each of the scale of Earth’s layers.
 Review all of the student calculations to ensure that they are correct.
Layer
Thick
Model
Notes
Crust
0-35 km 8½” circle
Radius 4.25”
Mantle
2,890 km 8” circle
Radius 4”
Outer Core
2,210 km 5½” circle
Radius 2.75”
Inner Core
2,440 km 2½” circle
Radius 1.25”
 Instruct the students to use the drawing compass. First they need to open the drawing
compass to the radius of the inner core. (Ask why they open to the radius?)
 Instruct the students to draw their circle of the inner core using their compass.
 Repeat for each of the other layers, using the radial measurements.
 Instruct the students to cut out each of the circles.
 Instruct the students to add information about each of these layers on their circles.
 Instruct the students to glue each of the layers to build their model of the Earth.
Example:
18
Lesson 6: Plate Tectonics
Materials (1 per student):
 1 handout per student
 scissors
 construction paper
 glue
 color pencils
Preparation:
 Gather materials
Directions:
 Discuss with the students:
o In 1911, Alfred Wegner was struck by the occurrence of identical fossils in
geological strata that are now separated by oceans. The accepted explanations or
theories at the time posited land bridges to explain the fossil anomalies; animals
and plants could have migrated between fixed separate continents by crossing the
land bridges. But Wegener was increasingly convinced that the continents
themselves had shifted away from a primal single massive supercontinent, which
drifted apart about 180 million years ago, to judge from the fossil evidence.
Wegener used land features, fossils, and climate as evidence to support his
hypothesis of continental drift. Examples of land features such as mountain ranges
in Africa and South America lined up; also coal fields on Europe matched up with
coal fields in North America. Wegener noticed that fossils from reptiles such as
Mesosaurus and Lystrosaurus were found in places that are now separated by
oceans. Since neither reptile could have swam great distances, Wegener inferred
that these reptiles had once lived on a single landmass that split apart.
o About 250 million years ago, all the continents collided into one supercontinent
called Pangaea. We see evidence of that collision today.
 Support for the theory of Plate Tectonics is fossil evidence. With a world map, discuss
the evidence.
 Distribute the map to the students. Instruct the students note the evidence on their map.
For example, in northern Brazil and central Africa, label “paleomagnetic stripes mirror
each other. In addition, color-code these clues for clarity.
 Instruct the students to cut out each of the continents.
 Direct the students to use their best guesses as to how the continents fit together. The
clues will provide support for their guesses.
 After everyone tries the best guess, distribute the Pangaea map. How close were they to
the leading hypotheses?
19
The Evidence In Support of Plate Tectonics
1. The paleomagnetic stipes or iron crystal patterns in the rocks of northern Brazil and
central Africa are mirror images of each other. Color Code: RED
2. There is evidence of glacier activity on both sides of the Atlantic Ocean along the
Equator. Color Code: ORANGE
3. Glossopteris is a genus of extinct seed fern (a Pteriosperm) whose fossils are found
throughout India, South America, southern Africa, Australia, and Antarctica. Color
Code: YELLOW
4. Mesosaurus was one of the first aquatic reptiles. Fossils have been found in South Africa
and South America. Color Code: GREEN
5. The age of the rocks in Europe and north America are the same, and get progressively
older as you move inland from the ocean. Color Code: LIGHT BLUE
6. Fossils of Lystrosaurus, a mammal-like reptile, are known from Antarctica, India, and
Africa. Color Code: DARK BLUE
7. Mountains in Greenland and Norway are almost identical in their geological structure.
8. The locations of earthquakes and volcanoes are not random. The occur along the margins
of the crustal plates. Color Code: PURPLE
9. The mountains of Scotland and the Appalachian mountains of north Americal are almost
identical in their geological structure. Color Code: Gray
10. The geological structure of southern Senegal and the Amazon Basin are almost identical.
Color Code: PINK
20
Instructions:
1. Color code the 10 clues that support the theory of plate tectonics.
2. Cut out each of the 7 continents.
3. Arrange each of the continents based on three lines of evidence:
a. How the continents look today
b. The shape of each of the continents
c. The 10 clues.
4. Examine Dr. Scotese’s map of the Permian. How close were you?
5. If you need to, rearrange your continents to the current hypothesis, and glue them to a
piece of paper.
21
Lesson 7: Plate Boundaries
Materials (1 set per group):
 Foam mattress cut into wedges as depicted below. You only need to cut 3 shapes. For
diagram D, you can use the two flat sides of your polygons.
 blue paper
 cardboard
 box
 scissors (or craft knife)
 color pencils or markers
Preparation:
 Cut foam mattress into the 3
defined shapes pictured to the
right.
 Cut box as pictured below
 Gather all materials.
Directions:
 Discuss that as the continents
move, that causes the continental
plates to do one of three things,
move apart, crunch together, or
grind past each other. This
lesson, students will be building
2 different models of these
boundaries.
 Distribute the prepared boxes.
Direct students to take two sheets of blue paper to represent the oceanic plate. On both sheets
place a triangular tube to represent the plate with an oceanic and continental crust. (Brown
cardboard works well.)
 Place the unattached sides of the papers through the slit so that only about half of the paper is
showing. Direct the student to reach in the opening on the side and slowly move the paper.
When one paper is pulled down, this represents the convergence of the plates. When the
paper is pushed up, this represents the divergence of the plates.
 Move only the sheet with the cardboard attached so that the cardboard comes to the edge of
the slit. This represents the ocean plate disappearing beneath the edge of the continent. This
is called subduction. This sinking of the oceanic plate into the mantle below the edge of the
22






continental crust results in "plate-pull" and may be one of the major forces driving plate
tectonics. Subduction also results in volcanic eruptions and very deep ocean trenches.
On the plain sheet of blue paper, attach another triangle so that this also has a continental and
an oceanic crust. Now pull both sheets of blue paper from the bottom. If you do this
carefully, one of the triangles will go on top of the other showing the development of
mountains when convergence occurs.
If the layers are moved toward the sides of the box, the students can see the action of fault
lines moving in an earthquake. This is called a transform fault.
For the next demonstration, students can work in groups of 2. Hand one set of the 3 foam
polygons the partners.
Working together, the students simulate the plates moving together (convergence), forcing
the wedge up. Ask the students to remove the wedge, and one student turn their polygon
over. Try this again. Note that one wedge is on top, and the other is force beneath it.
Working together, ask the students to simulate the plates moving apart (divergence), and the
wedge drops down. However, this thins the crust, and instead of getting a depression, there
is magma upwelling underneath the wedge. Direct one student demonstrate this by their
hand simulating magma, and gently pushing the wedge up higher than the two polygons.
Working together, ask the students to simulate the plates grinding past each other (transform
boundaries). The students will need to push both turn their polygons around, using the flat
sides. Direct the students to stand facing each other and gently press the foam towards each
other. Ask the student to move their foam to the right, which should cause the foam pieces to
travel in opposite directions.
Lesson 8: Rock Cycle
Materials (1 set per group of 4 students):
 Multicolor mini-marshmallows
 Plastic wrap – 4 pieces
 White frosting
 Plastic knife
In addition, set aside:
 Pan and hot plate (or electric skillet)
Preparation:
 Gather all materials.
Directions:
 Discuss the rock cycle.
 To demonstrate it, direct all students to wash their hands with soap and warm water.
 Distribute the plastic knife, color marshmallows and frosting to groups of students
(generally 4 students can easily share one can of frosting). Give a piece of wax paper and
a piece of plastic wrap to each student as a work surface.
 Sedimentary rock is made by pieces of metamorphic, sedimentary, or igneous rock
(weathered into smaller and smaller particles) and then cemented together with minerals.
To represent sedimentary rock, direct the students to make two layers of marshmallows,
23



and each layer is a total of 8 marshmallows. Students will need 16 marshmallows total.
To represent the minerals that cement the smaller pieces together, the students will use
the white frosting. BE SURE TO TELL THE STUDENTS
THAT THIS SHOULD BE DONE ON TOP OF THE PLASTIC
WRAP.
When the students have completed their sedimentary rocks, they
will model metamorphic rock. This rock is formed through
pressure and heat. It can be metamorphic, sedimentary, or
igneous rock. To simulate this, direct the students to loosely
wrap their marshmallow in the plastic wrap. The heat and
pressure will come from their hands. Have them squish their
marshmallow between their hands while you continue to discuss
the rock cycle with them. This may take a bit of time, and their arms may get tired. Give
them a break, and then back at it. Just like metamorphic rock, it doesn’t happen in a
second, or a minute. When the marshmallows squish and stick together, you have
completed the metamorphic stage.
To demonstrate igneous, those metamorphic rocks get buried, however igneous rock can
be metamorphic, sedimentary, or igneous rock. As it gets buried further down, it melts,
and becomes igneous rock. To demonstrate igneous, direct the students to bring you their
marshmallows. Place them in the pot or electric skillet, and melt them. If you do this
over low heat, you will see spots of different colors. When the marshmallows have
melted, place them in the freezer overnight.
The remaining step will be conducted on the next lab.
Lesson 9: Minerals
Materials (1 set per student):
 Three clear plastic cups (short and wide are better than tall and thin)
 1 pint canning jar
 Distilled water
 3 craft sticks
 Epsom salts
 Black construction paper
 Scissors
 Pipe cleaner
 Borax
 Pencil
 String
 Mrs. Stewart’s bluing
 Ammonia
 Table salt
 Food coloring
 Charcoal briquettes
 Hand lens
In addition, set aside
24


Hot plate and pot or other method of making hot water
Pot holder
Preparation:
 Gather all materials.
Directions:
 Students will make 3 crystal recipes using different minerals. When the crystals have
grown, they will examine the crystals and classify them according to their crystalline
structure.
 Recipe #1:
o Use the scissors to cut black construction paper so that it will fit in the bottom of the
cup, and put it in the bottom of the cup.
o In another cup, add 1 teaspoon of Epsom salt to 1 tablespoon of very warm water. Stir
with the craft stick until the salt is dissolved.
o Pour the salt solution over the paper.
o Put the cup in the place where it will remain undisturbed.
o Rinse out your mixing cup.
 Recipe #2 (conduct this experiment in the morning. Check results before going home.)
o Cut a pipe cleaner into three equal sections.
o Twist the sections together at their centers to form a six-sided shape. The pipe cleaner
should fit inside the jar, but not touch the bottom.
o Tie the string to the end of one of the arms. Tie the other end of the string to the
pencil. You want the pipe cleaner to hang into the jar, but not all the way to the
bottom.
o Add 1 cup of boiling water to the jar.
o Add 3 tablespoons borax to the water. It is okay if some undissolved borax settles to
the bottom of the jar.
o Add food color.
o Hang the pipe cleaner snowflake into the jar so that the pencil rests on top of the jar
and the snowflake is completely covered with liquid and hangs freely (not touching
the bottom of the jar).
o Allow the jar to sit in an undisturbed location during the day or overnight.
o Allow the crystals to continue to grow.
 Recipe #3 (this one will not be visible right away, and your students will need to revisit it
later)
o Place chunks of your charcoal briquette in an even layer in the bottom of your cup.
You will need smaller pieces (largest about 1-inch in diameter), so use a hammer to
break the material.
o Sprinkle distilled water, onto the briquette until is has been thoroughly dampened.
Pour off any excess water.
o In an empty cup, mix 1 tablespoons uniodized salt, 1 tablespoons ammonia, and 2
tablespoons bluing. Stir until the salt is dissolved.
o Pour the mixture over the briquette.
o Add and swirl a bit of water around in the empty jar to pick up the remaining
chemicals and pour this liquid onto the substrate, too.
25


o Add a drop of food coloring here and there across the surface. Areas with no food
coloring will be white.
o Sprinkle more salt (about 1 T or about 30 ml) across the surface.
o Set the cup in an area where it will not be disturbed.
o On days 2 and 3, pour a mixture of ammonia, water, and bluing (1 tablespoon) in the
bottom of the pan, being careful not to disturb the delicate growing crystals.
o Keep the pan in an undisturbed place, but check on it periodically.
After the crystals have grown, give each student a piece of black construction paper and a
hand lens. Students will now classify what category each crystal belongs.
There's more than one way to categorize a crystal! The two most common methods are to
group them according to their crystalline structure and to group them according to their
chemical/physical properties. We will be using the crystalline structure.
26
Crystalline Shapes
Using your hand lens, determine what shape your crystals have.
Cubic or Isometric - not always cube shaped! You'll also find
octahedrons (eight faces) and dodecahedrons (10 faces).
Tetragonal - similar to cubic crystals, but longer along one axis
than the other, forming double pyramids and prisms.
Orthorhombic - like tetragonal crystals except not square in
cross section (when viewing the crystal on end), forming
rhombic prisms or dipyramids (two pyramids stuck together).
Hexagonal - six-sided prisms. When you look at the crystal onend, the cross section is a hexagon.
Triclinic - usually not symmetrical from one side to the other,
which can lead to some fairly strange shapes.
Monoclinic - like skewed tetragonal crystals, often forming
prisms and double pyramids.
27
Lesson 10: Rocks
Modified from: http://geology.about.com/od/rocks/tp/rocks101.htm
Materials (1 set per group of students):
 Rocks 1 or 2 of each of the following:
o Igneous
o Metamorphic
o Sedimentary
 Hand lens
 White unglazed ceramic tile
 Black unglazed ceramic tile
 Paper clip
 Penny
 Nail
 HCl (dilute solution)
 Magnet
 Water
 100 ml graduated cylinder
 Scale or balance
 Copies of
o Rock Sorting Student Directions
o Student Data Collection Sheet
o Words List
Preparation:
 Gather all materials.
 Divide students into teams
 Distribute
o supplies
o Rock Sorting Student Directions
o Student Data Collection Sheet
o Rock Description “Words List”
28
1.
2.
3.
4.
5.
Rock Sorting Student Directions:
Sort the rocks into groups based on any characters you and your lab partners
choose. Record how you group your rocks.
Select different characteristics, and sort the rocks. Record.
a. Do you think one way of classifying is more informative than the other?
Rocks get dirty and decay: wind and water make every kind of rock slowly
break down, the process called weathering. You want to observe fresh. Now
take out your magnifier. Find good light and examine the rock's fresh color.
Overall, is it dark or light? What colors are the different minerals in it, if those
are visible? What proportions are the different ingredients? Sketch the rock on
the reverse side of your data collection sheet.
a. –Color:
i. –Draw a line on the white streak plate and record the color(s) of the
streak
ii. –Draw a line on the black streak plate (if available) and record the
color(s) of the streak
iii. –Dampen rock and record color(s)
b. –Luster: How does the rock reflect light? Is it:
. –Glassy vitreous – shines like glass
. –Earthy, chalky – dull
. –Metallic – looks like metal
. –Waxy, silky, pearly – has muted shine
Some rock characteristics are the weight/volume (specific gravity), and if the
rock is magnetic.
a. –Specific Gravity: What is the mass in grams?
. –Mass the rock in grams
. –Use the graduated cylinders to find the volume of the rock (record
the volume of water before adding the rock, and after adding the rock.
The difference is the volume of the rock.
. –Calculate (HOORAY, MATH!!!) g/ml
. –Example: 12.3g/3.1ml = 3.97g/ml
b. –Magnetic: Is the rock magnetic or do magnets stick to it?
. –Does a paperclip stick to the rock? Record result.
. –Does the magnet stick to the rock? Record result.
For a chemical reaction analysis, you can use your sense of smell, and a dilute
Hydrochloric Acid.
a. –Smell: How does the rock smell?:
i. –Earthy
ii. –Sour
iii. –Sweet
29
6.
7.
8.
9.
iv. –Rotten eggish
v. –Other
b. –Chemical: Does HCl react?
i. Add a drop and observe. Record the results
Observe the rock's texture, close up. What kind of particles is it made of, and
how do they fit together? What's between the particles? This is usually where
you may first decide if your rock is igneous, sedimentary or metamorphic. The
choice may not be clear. Observations you make after this should help confirm
or contradict your choice.
a. Igneous rocks cooled from a fluid state and their grains fit tightly. Igneous
textures usually look like something you might bake in the oven.
b. Metamorphic rocks are rocks of the first two types that were changed by
heating and stretching. They tend to be colored and striped.
c. Sedimentary rocks consist of sand, gravel or mud turned to stone.
Generally they look like the sand and mud they once were.
Observe the rock's structure, at arm's length. Does it have layers, and what size
and shape are they? Do the layers have ripples or waves or folds? Is the rock
bubbly? Is it lumpy? Is it cracked, and are the cracks healed? Is it neatly
organized, or is it jumbled? Does it split easily? Does it look like one kind of
material has invaded another?
a. –Feel: When you touch it, does it feel
i. –Gritty or sandy
ii. –Powdery, earthy, or chalky
iii. –Smooth like glass
iv. –Smooth and sticky or waxy
v. –Sharp and metallic
Mohs Test of Hardness is the last important set of observations. You need your
fingernail, a penny, and a nail.
a. Using your fingernail, can you scratch the rock? If so, stop here and
record.
b. Using a penny, can you scratch the rock? If so, stop here and record.
c. Using a nail, can you scratch the rock? If so, stop here and record. This is
a quick and simple version of the 10-point Mohs scale of mineral hardness:
nail is usually hardness 5-1/2, coins are hardness 3, and fingernails are
hardness 2.
d. Be careful: a soft, crumbly rock made of hard minerals may be confusing.
If you can, test the hardness of the different minerals in the rock.
After completing these different assessments, use this information to sort your
rocks one more time.
a. Is it different than your first time? In what ways is it different?
30
Character
Student Data Collection Sheet
Rock 1
Rock 2
Rock 3
Color
White Streak
Plate color
Black Streak
Plate color
Luster
Specific
Gravity (g/ml)
Paper clip
sticks to rock?
Magnet sticks
to the rock?
Smell
Rx with acid?
Igneous,
Metamorphic,
or Sedimentary
Feel
Hardness fingernail
Hardness penny
Hardness - nail
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Sketch of Rock #1:
Sketch of Rock #2
Sketch of Rock #3
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Rock Description “Words List”
Colors
white
colorless
clear
beige
dirty-white
red
purple
mauve
pink
salmon pink
blue
bluish
turquoise
green
silvery -yellow
gray
silver
black
golden
gold-colored
yellow
bronze
brown
creamy
copper-colored
dark
very dark
speckled
banded
Other words to describe colors
deep
shiny
dull
light
pale
bright
splotchy
streaked
layered
Luster
Word
dull / earthy
Description
very dull, mainly in minerals that are porous
Example
kaolinite, orthoclase
waxy
opal, chalcedony
greasy / oily
nepheline
pearly
like a pearl, play of colours, light
silky
talc, some micas
some varieties of gypsum, kernite,
ulexite & in fibrous minerals
glassy /
vitreous
looks like glass
quartz, many rock-forming minerals
obsidian – "nature’s glass"
resinous
looks like freshly-broken shellac, usually yellowbrown
sphalerite
adamantine
high lustre, almost brilliant
sphalerite
submetallic
silvery or metallic lustre but mineral is transparent or
translucent when in small slivers
hematite
metallic
highly reflective, opaque minerals
pyrite, gold, silver
Other words that describe luster
shiny
sparkles
milky
shimmering
opalescent
frosted
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Transparancy
transparent
clear, see right through it when it is sliced thin
- quartz crystal,
celestite, selenite
translucent
see shapes & shadows through it when it is sliced thin, chemical
impurities can cause the mineral to be cloudy
- calcite, quartz,
sphalerite
opaque
can’t see light through it at all when it is sliced thin
- metals, gypsum
Specific Gravity
Description
SG
Mineral examples
very light
<2
borax
light
2–3
quartz, calcite, halite, dolomite, ulexite, gypsum, turquoise, talc,
muscovite, biotite
heavy
3–5
barite, chalcopyrite, fluorite, celestite, apatite, almandine garnet
very heavy
5 – 10
nickel-iron, galena, pyrite, magnetite
extremely heavy
> 10
silver, gold
Reaction with Acid
Yes?
Calcium carbonate
Magnetic
Yes?
Magnitite
Other
Moh's Scale of Hardness
Rating
Description
Mineral example
1 SOFT
Easily crumbles. Can be scratched with a fingernail (2.2).
Talc
2
Can be scratched with a fingernail (2.2).
Gypsum, Soapstone (impure talc)
3
Can be scratched with a copper penny (3.5).
Calcite
4
Can be scratched with a common nail.
Fluorite
5
Can be scratched with a piece of glass (5.5).
Apatite
6
Mineral of hardness 6 or more will scratch glass.
Feldspar, Orthoclase
7
Quartz
8
Topaz
9
Corundum
10 HARD
Diamond
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Week 3 – Scientific Method
Suggestion
http://chemistry.about.com/cs/sciencefairideas/a/aa072903a.htm
Growing crystals is a fun way to explore your interest in chemistry and geology. There are lots of
types of crystals that can be grown from common household substances, such as sugar (sucrose),
salt (sodium chloride), Epsom salts, borax, and alum. Sometimes it's interesting to mix different
materials to see what types of crystals result. For example, salt crystals look different when they
are grown with vinegar. Can you figure out why?
If you want a good science fair project, it would be better if you tested some aspect of growing
crystals rather than simply growing pretty crystals and explaining the process. Here are some
ideas of ways to turn a fun project into a great science fair or research project:
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How does the rate of evaporation of the crystal-growing medium affect the final size of
the crystals? You can change the rate of evaporation by sealing the container (no
evaporation at all if there is no air space) or by blowing a fan over the liquid or enclosing
the jar of medium with a dessicant. Different places and seasons will have different
humidities. The crystals grown in a desert may be different from those grown in a rain
forest.
You will usually heat water or another liquid to dissolve a solid to grow your crystals.
Does the rate at which this liquid is cooled affect the way the crystals grow? You can
compare crystals allowed to cool at room temperature to those formed from cooling the
liquid in a refrigerator.
What effect do additives have on the crystals? You could add food coloring, flavorings,
or other 'impurities'. How do crystals grown from uniodized salt compare with those
grown from iodized salt?
What steps can you take to maximize crystal size? Developing a procedure is a form of
experimental science. You can affect parameters such as vibration, humidity,
temperature, rate of evaporation, purity of your growth medium, and time allowed for
crystal growth. The type of container used to grow your crystals may make a difference,
as could the type of string used to suspend a seed crystal (or other method used to grow a
crystal). Are you changing containers when crystals start to grow that could compete with
your seed crystal? There are lots of things to think about! Some may have a major effect
on crystal growth and others may be negligible. Does light/dark affect growth? Probably
not for a salt crystal, but it could for a substance that is degraded by visible radiation.
If you are up for a challenge, you can make predictions about the shapes of crystals
before you grow them, based on their molecular structures and molecular geometry.
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