Download Learning About Layers-Rocks

Topic
Rocks
Materials
For each student group:
a one-liter bottle with lid
soil, sand, and pebbles (see Management 1)
funnel (see Management 2)
sedimentary rocks (see Management 5)
hand lens
water source
Key Question
How can models, drawings, and reading passages help
you understand some ways that rocks form in layers?
Learning Goals
Students will:
• model how sediment layers can form rocks,
• read about sedimentary rocks, and
• identify some of the ways that sedimentary rocks form.
Background Information
Sedimentary rocks are made up of materials that
were once a part of another rock. These parts were
deposited as layers of loose materials. These parts are
called sediments. Most sediment is deposited on ocean
floors or at the bottom of rivers and lakes. Over time
the loose sediments are formed into solid rocks.
Sedimentary rocks are classified into three groups.
They are grouped based on what the original sediments
were. Clastic sedimentary rocks form from layers of sediments. Pressure causes the water around the sediments
to be squeezed out and the sediments are cemented
together. Sandstones, shales, and conglomerates form
this way.
Chemical sedimentary rocks form when rock fragments dissolve in water. Over time the water evaporates
and the minerals that were in the rock crystallize into
large deposits. Rock salt and gypsum form this way.
Organic sedimentary rocks form from the sedimentary remains of shells, skeletons, and other plant and
animals parts. Limestones and coals form this way.
Guiding Documents
Project 2061 Benchmarks
• 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.
• Models are often used to think about processes that
happen too slowly, too quickly, or on too small a scale
to observe directly, or that are too vast to be changed
deliberately, or that are potentially dangerous.
NRC Standard
• Some changes in the solid earth can be described
as the “rock cycle.” Old rocks at the earth’s surface weather, forming sediments that are buried,
then compacted, heated, and often recrystallized
into new rock. Eventually, those new rocks may
be brought to the surface by the forces that drive
plate motions, and the rock cycle continues.
Management
1. You will need to gather builder’s sand, potting soil, and
small pebbles. These will be called Earth materials as
well as sediments in this activity. Students will need
to understand that these materials come from rocks
that have been broken down as a result of weathering.
The soil also contains organic materials.
2. You will need funnels that will permit the students
to easily place the sand, soil, and pebbles into the
bottles. Paper funnels sold to pour oil into cars are an
inexpensive source for these.
3. Prepare one bottle with the three types of sediments and
a second bottle with the three sediments and water.
4. Tell the students to fill the containers half-full with
the three Earth materials and to pour in water so
that the bottle is three-fourths full.
5. You will need samples of conglomerates, sandstones,
limestones, and shales for each group.
Science
Earth science
rocks and minerals
Integrated Processes
Observing
Comparing and contrasting
Relating
Communicating
Collecting and recording data
Interpreting data
Inferring
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© 2006 AIMS Education Foundation
7. Tell the students to tighten the cap of the bottle and
shake the bottle. Direct them to place the bottles
in the center on the group and observe and record
what they see happening in the bottle. Encourage
them to use the hand lens when making observations. Distribute the sedimentary rock samples and
have the students identify which layer they think the
sample is most like. [The conglomerates are most
like the bottom layer, the sandstone and limestone
most like the middle layers, and the shale most like
the top layer.]
8. Tell the students to gently turn the bottle upside
down. Have them observe and record what they
see happening in the bottle.
9. Distribute the reading passage on Learning about
Layers. Have the students read and respond to the
questions.
Procedure
1. Ask the Key Question and state the Learning
Goals.
2. Show the students the three Earth materials. Direct
the students in a discussion about these Earth
materials. Make sure the students understand that
these materials are called sediments.
3. Point out to the students that these three materials
came from other materials. The sand and pebbles
are smaller pieces of rocks that have been broken
down by processes on the Earth. The soil is a
combination of sand and rocks as well as organic
materials. Organic means that it was once living.
Examples of organic materials found in the soil are
decaying roots, leaves, as well as insects.
4. Direct the student’s attention to the bottle that has just
the Earth materials in it. Ask the students what Earth
materials are in the container. (They may or may not
be able to see the different type of materials.)
5. Show them the container with the Earth materials
and the water. Ask them what they think the water in
the bottle represents in this model. [It represents the
moving water.]
6. Distribute a bottle with lid and hand lens to each
group. Direct each student group to place the three
Earth materials into their bottle and add water.
Core Curriculum/Oklahoma
Connecting Learning
1. In your own words, describe how sediments form
layers.
2. What can happen to these layers over time?
3. Why is it useful in science to use models as well
as drawings when you are learning about how
rocks form?
4. What role does water play in the formation of rocks?
5. What are you wondering now?
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© 2006 AIMS Education Foundation
Key Question
How can models, drawings,
and reading passages help
you understand some ways
that rocks form in layers?
Learning Goals
• model how sediment layers can
form rocks,
• read about sedimentary rocks, and
• identify some
of the ways that
sedimentary
rocks form.
Core Curriculum/Oklahoma
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© 2006 AIMS Education Foundation
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Modeling Sedimentary Rocks
1.
2.
3.
4.
Pour soil, sand, and pebbles into the bottle.
Add water and shake.
Observe the particles in the jar.
Sketch and describe the layers.
Describe
Sketch
5. Slowly turn the bottle upside down.
6. Sketch and describe.
Describe
Sketch
In your journal, describe how this shows one way sedimentary rocks form.
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7
The last kind of sedimentary rock forms
from the remains of shells, skeletons, and
other plant and animals parts. Over time the
pressure of soil turns things into layers of
rocks. Limestones and coals form this way.
Sedimentary rocks are made up of
pieces of other rocks. These pieces
are called sediments. Sediments get
carried by wind, water, or ice and then
are deposited in layers.
Have you ever stirred sugar in water
and watched it dissolve? If you
let the water evaporate, a layer of
sugar will be left in the bottom of
the glass. Rock salt and gypsum
form this way.
sugar in
water
layer of
sugar
1
6
3
4
Imagine placing a wet sponge
between the palms of your hands
and squeezing it. The water
is squeezed out and the once
plump layer of sponge becomes
a thinner layer. Sandstones,
shales, and conglomerates form
this way.
One kind of sedimentary rock is formed
from layers of sediments. Pressure
causes the water around the sediments
to be squeezed out and the sediments are
pushed together.
Most sediments are deposited on
ocean floors. They can also be
deposited at the bottom of rivers and
lakes. Over time the loose sediments
form into layers of solid rocks.
Another kind of sedimentary rock forms
when rock fragments dissolve in water.
Over time the water evaporates and the
minerals that were in the rock turn back
into large layers of crystals.
5
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© 2006 AIMS Education Foundation
Connecting Learning
1. In your own words, describe
how sediments form layers.
2. What can happen to these layers
over time?
3. Why is it useful in science to
use models as well as drawings
when you are learning about how
rocks form?
4. What role does water play in the
formation of rocks?
5. What are you wondering now?
Core Curriculum/Oklahoma
61
© 2006 AIMS Education Foundation