Earth and Space Science Assessment Probes
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ls lt a Rock? (Version 2)
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What is a rock? How do you decide if something is a rock?
Put an X next to the things that You think are rocks.
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a
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block
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-cement
dried mud
Piece of claY Pot
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coral
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hardened lava
limestone
asPhalt (road tar)
iron ore
-gl"t.
!
*
concrete
coal
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brick
a gravestone
marble statue
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granite
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*
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Explain your thinking. \flhat "rule" or reasoning did you use to decide
I
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is a rock?
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Uncoverin$ Student ldeas in Science
L57
Earth and Space Science Assessment Probes
ls !t a Rock? (version 2l
Teacher Notes
Purpose
Some rocks, such as limestone, are composed
The purpose of this assessment probe is to elicit
almost entirely of.one
students' ideas about rocks. The probe is designed
impure masses of calcite. Other rocks occur
to determine whether students can distinguish
aggregates of two or more minerals. For exam-
between human-made, "rock-like" materials and
ple, granite is a common rock composed of the
geologically formed rock material of various ori-
minerals quartz, hornblende, and feldspar.
gins, even though it may have been shaped by hu-
few rocks are composed of nonmineral matter.
mans. The probe reveals whether students have a
Pumice is a volcanic rock formed by the cool-
geologic conception ofa rock.
ing of frothy lava. Coal is a rock formed by the
mineral-in this case,
as
A
hardening of solid organic debris.
Related Concepts
158
Some of the items on the list are rock-like
minerals, rocks
in that they are similar to rock material but
are not naturally formed through geologic
Explanation
processes. The cement block, piece of clay pot,
The items on the list that are rocks are coal,
brick, asphalt, glass, and concrete are all made
hardened lava, limestone, a gravestone, iron
using some rock material, combined with oth-
ore, marble statue, and granite. Simply, a rock
er materials, and reshaped through a human-
can be defined as any solid mass of mineral or
made process, not a geologic one. The material
mineral-like matter that occurs naturally as
part of our planet (Lutgens and Tarbuck2003)'
itself is not "rock." However, the gravestone
and marble statue are rock, even though they
National Science Teachers Association
Earth and Space Science Assessment Probes
unchanged. The material is still rock, only the
combining materials from the environment
in new ways, based on the properties of the
materials. Students comPare and classify familiar human and naturally made objects
and materials, and they investigate unfa-
shape and texture have changed.
miliar materials to find out what they
have been reshaped and polished through a
human-made process, because the material
they are made of was formed through a 1eologic process and the original composition is
Coral is made by living processes' not geo-
are
made of.
logic processes. Soft-bodied organisms secrete
calcium carbonate to make hard, rocklike
casings that protect their soft bodies. These
"community casings" result in the formation
ofcoral
reefs.
Mud is a mixture of silt, clay, and water.
Silt and clay are fine rock fragments. Mud can
dry out, forming hard cakes that appear rocklike. However it takes long periods of geologic
time for dried mud to harden (lithifi') into
solid sedimentary rock such
as shale.
Gurricular and lnstructional
Gonsiderations
Middle School Students
Students continue to refine their ideas about
how natural objects such
as rocks are formed.
They can contrast composition and formation of human-made materials with naturally
formed ones. They begin to develop an understanding of how rocks are formed through various geologic processes, resulting in a variety of
sedimentary, igneous, and metamorphic rocks.
Students can begin to trace the composition
of rocks and minerals back to the geologic
that formed them. They can contrast this formation with short-term human
processes
processes developed through materials science
Elementary Students
Observing and classifying objects and materials is a major part of elementary science in-
quiry. Younger elementary students should
become familiar with the variety of objects
and materials in their local environment, including rocks and objects made from rocks'
Ideas about rocks are linked to ideas about
properties of matter. They begin to under-
stand that rocks can come in natural forms
or can be cut, shaped, and polished by humans for various uses. They begin to understand how some objects and materials exist
naturally and others are made by humans
Uncovering Student ldeas in Science
and technology that result in rockJike materi-
als such as cement.
In their study of natural
resources, they recognize that rock is a natu-
ral resource that can be reshaped by humans
without changing its composition or can be
crushed and combined with other materials to
form
a new, hard material.
High School Students
Student at this level refine their understanding
of the geologic processes that form rocks as well
as an understanding of the chemical composi-
tion and origin of minerals that make up rocks'
159
=
Earth and Space Science Assessment Probes
They have a greater awareness of the long-term,
them useful in different ways, for example,
geologic processes that form rocks. They learn
as building materials, as sources
about chemical processes, invented by humans,
or for growing the plants we use as food.
which result in rockJike mixtures such as
Earth materials provide many of the re-
phalt, concrete, and cement.
In biology
as-
of fuel,
sources that humans use.
they
recognize living processes that form hard, rock-
like casings such
as
K-4 Types of Resources
coral and mollusk shells and
e
link this to the idea of biogeochemical cycles.
At this level, combined with their knowledge
of chemistry, students have greater familiarity
with synthetically produced materials and are
more apt to differentiate them from materials
Some resources are basic materials such
as air, water, and soil; some are produced
from basic resources, such as food, fuel,
and building materials.
5-8 Structure of the Earth System
produced through geologic processes.
o
Some changes in the solid Earth can be de-
Administering the Probe
Make sure younger students understand the
scribed as the "rock cycle." Old rocks at the
words on the list. You may choose to show ex-
that are buried, then compacted, heated,
amples (actual or photographic) of the materials
and often crystallized into new rock. Even-
or point out examples they are familiar with in
tually, those new rocks m'ay be brought to
their local environment, such as a cement side-
the surface by forces that drive plate mo-
walk. \7ords can also be written on cards or
tions, and the rock cycle continues.
Earth's surface weather, forming sediments
combined with pictures and used as a card sort
9-L2 Geochemical Cycles
activity, sorting cards into "rock" and "non-
o
rock." For older students who are familiar with
Each element on Earth moves among reser-
examples of igneous rocks, consider replacing
voirs in the solid Earth, oceans, atmosphere,
the term hardened lauawith basah or pumice.
and organisms
as
part of geochemical cycles.
9-L2 Natural Resources
Related ldeas in National
Science Education Standards
.
(NRC 1es6)
Human populations use resources in the
environment in order to maintain and improve their existence.
K-4 Properties of Earth Materials
*
Related ldeas in Bench marks
for Scien ce Literacy (AAAS
1e98)
Earth materials are solid rocks and soils,
water, and the gases of the atmosphere.
The varied materials have different physi-
cal and chemical properties, which make
E lndicates a strong match between the ideas elicited
160
bythe probe and a national standard's learninggoal.
National Science Teachers Association
-lE-
Earth and Space Science Assessment Probes
of rocks, based on their composition.
Emphasize the long periods
of
Related NSTA Science Store
Publications and NSTA Journal
geologic
time it takes to make rock and review the
stages
Articles
ofthe rock cycle versus the short pe-
riod of time to make
American Association for the Advancement of Sci-
a brick.
ence (AAAS). 1993. Benchmarks
'When younger elementary students describe
eraq'.
physical properties ofobjects, include rocks
in the study of properties.
NewYork Oxford Universiry
ence
Press.
Driver, R., A. Squires, P Rushworth, and V.
Robinson. 1994. Making
same. For example, show students a rough
science: Research
of granite and a smooth,
lit-
and Children (Oct.):25-26.
erty may change, but the material is still the
piece
science
Damonte, K. 2004. Going through changes. .9rl-
Rocks can be
to demonstrate how a physical prop-
used
for
polished
sense
of
\food-
secondary
into childrenls ideas. London:
RoutledgeFalmer
of granite, noting that they are sdll
the same material although the property of
Ford, B. 1996. Projeo Eartlt science: Geologt Arling-
texture has been changed by humans.
Keeley, P. 2005. Science curriculum topic study:
piece
Compare and contrast naturally formed objects
with objects made or reformed by hu-
In the latter category have students
place objects into two groups: (1) those
mans.
made entirely from natural materials that
have not been recombined when reshaped
by humans (e.g., the marble statue) and Q)
those that contain some natural material,
combinedwith other materials to make new
material that does not exist in
a
con,
VA: NSTA
Press.
Bridging the gap between standards and practice.
Thousand Oaks, CA: Corwin Press.
National Research Council (NRC). 1996. National
science education standards.
\Tashington, DC:
National Academy Press.
Plummer, D., and
\(
Kuiman. 2005. Rocls in our
pockets. Science Scope 29 (2): 60-61.
Varelas,
M., andJ. Benhart. 2004. \Telcome to rock
day. Science
6
Children 40 (1):
4045.
natural state
(e.g., concrete or brick).
Have students investigate the materials
that make up brick, concrete, cement, and
asphalt. Connect this to materials science
and technology, noting how humans
use
natural resources and scientific knowledge
about materials to make new types of materials for construction.
t62
National Science Teachers Association
Earth and Space Science Assessment Probes
o
K-2 The Structure of Matter
* Objects can be described in terms of the
,.
i:.i
ffi
Some students regard rock as being made
of only one substance and thus have difficulty in recognizing granite as rock (Driver
materials they are made uP of.
et al. 1994).
o
3-5 Processes That ShaPe the Earth
* Rock is composed of different combinations of minerals.
In studies by Happs (1982,1985), students
had difficulty making the distinction between "natural" things and those created
or altered by humans. For example' some
3-5 Materials and Manufacturing
. Through science and technology, a wide
students considered brick a rock because
part of it comes from natural material'
variety of materials that do not appear in
Conversely, some students thought cut,
smooth, polished marble is not a rock be-
nature at all have become available.
cause humans made
it smooth and so it
is
no longer natural (Driver et al. 1994).
6-8 Processes That ShaPe the Earth
* Sedimentary rock buried deep enough may
r \fhen students were shown different types of
rock and asked whether they were rocks, several students thought pumice was too light to
be reformed by pressure and heat, perhaps
melting and recrystallizing into different
kinds of rock. These reformed rock layers
may be forced up again to become land
be a rock (Osborne and Freyberg 1985).
surface and even mountains. Subsequently,
this new rock will erode. Rock bears evidence of the minerals' temperatures, and
Su$$estions for lnstruction and
Assessment
. \(hen teaching about rocks, take time to
elicit students' conception of what a rock
forces that created it.
Although students may have had several
opportunities to study rocks during their
is.
g-L2 Processes That Shape the Earth
r The formation, weathering, sedimenta-
K-B experiences' do not
assume that they
tion, and reformation of rock constitute a
continuing "rock cycle" in which the total
have a correct conception of what a rock
is. Students may be able to define a rock,
amount of material stays the same as its
name tyPes of rocks, and describe the geo-
form changes.
logic processes that formed them, yet they
may still identify human-made materials,
Related Researeh
. The word rock is used in many different
o
DeveloP an operational definition before
ways in our common language, contribut-
introducing the scientific definition' Stu-
ing to the confusion of what it means in
dents need
a
geologic sense (FreYberg 1985)'
*
such as brick, as rocks.
to
understand what minerals
are before they develop a scientific notion
probe and a national standard's learning goal'
lndicates a strong match between the ideas elicited by the
Uncovering Student Ideas in Science
161
Earth and Space Science Assessment Probes
Happs, J. 1985. Regression in learning outcomes:
References
American Association for the Advancement of Science (AAAS). 1993. Benchmarhsfor science
erary. New
York Oxford University
Driver, R., A. Squires,
P.
of
secondary
into
child.ren's ideas.
London:
sense
P 1935. Implications
across
the curricu-
lum. In Learning in science, eds. R. Osborne and
P.
Freyberg, 125-1'35.Auckland, New Zealand:
P (2005). Science cuniculum topic study:
Bridging the gap between standards and practice.
Thousand OaIa, CA: Corwin Press.
Lutgens, F., and E. Thrbuck. 2003. Essentials of geol'
Happs, J. 1952. Rochs and mineral's. LISP'Working
Hamilton, New Zealand. Universiry
of\flaikato, Science Education
Hall.
Nadonal Research Council (NRC). 1995. National
s
cienc
e edacation standards.'Washington, DC:
Nadonal Academy Press.
Heinemann.
Paper 204.
science. European
ogy. 8th ed. Upper Saddle fuver, NJ: Prentice
RoutledgeFalmer.
Freyberg,
Eartl
Journal of Science EducationT (4):431443.
Keeley,
Press.
Rushworth, andV \7ood-
Robinson. 1994. Mahing
science: Research
lit'
Some examples from
Research
Unit.
Uncovering Student ldeas in Science
Osborne, R., and P Freyberg. 1985' Learning in science: The implications of childrenls science.
Auck'
land, New Zealand: Heinemann.
163