Unit: Earth’s Materials
Lesson Title: Shake it up baby!!
Topic: Physical weathering through abrasion.
Focus Question: What effect does hardness of a rock sediment and the length of time a
rock is weathered have on the way rock particles are changed by physical weathering?
Demographics:
This lesson could be used in any Earth Science class, but is currently being used
in an 8th grade non-regents earth science class. The class size is 25 students, 11 girls and
14 boys. The students in this class reflect the socioeconomic make up of the school,
which is predominantly lower to middle - middle class. Though white students compose
90% of the racial composition of the sand creek middle school, as a whole approximately
50% of this class is racial minorities. This class has several students with diagnosed
learning problems as documented by their IEP. Specifics of each child’s IEP are given in
the Unit Plan Demographics.
This lesson is part of the Earth’s Materials Unit and is being taught after an
introduction to weathering and erosion. The lesson is a lab activity that is designed to
provide a concrete example of topics that have been covering previous lessons on the
weathering process.
The students will gain an appreciation of how time and rock type or hardness
affect the weathering process during this lesson. At the completion of the lesson should
be able to state the relationships that control this process. During the lesson students will
be asked to manipulate rock samples, record data, graph the results and then answer
questions related to the experiment, the results and their graph. It is important that
students have some working knowledge of how to graph data and how to use and electric
balance.
Two 40-minute periods (over two days) will be used to complete this lesson. The
instructor will introduce the students to the questions of study for the lab, explain the
procedures and then control the timing of the experiment. Students are then given time to
work on their own to complete calculations, graph data and answer questions. A portion
of the flowing instructional period is given to finish the lab and give closure to the lesson.
The classes in which this lesson will be taught are 40 minutes long and take place
5th and 6th periods of a 9 period day. These periods occur just after the students have
come back from lunch and they often need additional time and coaching to settle into
lessons. The anticipatory set used on the first day of the lesson is design to do help
students settle and focus on the material to be covered in the lesson.
Statement of Intent:
In this lesson students will explore how time and composition of rock (rock type
affect the weathering process. Different rocks weather at different rates based on their
composition, but it is important for students to recognize that all rocks, regardless of
composition, weather more with time. This laboratory style lesson asks students to shake
several rock types for multiple intervals of time and to record the mass of the rocks after
each interval. In doing so, students will be able to observe that the rock fragments are
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loosing mass over time. They will also observe that the different rock types lose mass at
different rates. After the activity portion of the lab, students are asked to graphically
represent the relationship between time and weathering for each of the rock types. Prior
knowledge of weathering, the experience during the lab activity and the graphs will help
students to complete the post lab questions related to the amount of weathering
experienced by their rock fragments.
It is assumed that students will have prior knowledge of the weathering process
from previous portions of their Earth Science curriculum. In previous units the students
have learned about the physical properties of matter including mass. The ability to record
data, graph multiple data sets and to interpret graphs is also necessary for successful
completion of this lab exercise. Additionally students should be familiar with electric
balances.
Objectives:
After completing this lab students will be able to:
1. State the relationship between rate of physical weathering and rock particle
hardness.
2. Compare the changes that occur to rock particles as they are abraded over
time.
Rationale:
The following New York State Mathematics, Science and Technology Learning
Standards for the intermediate level (5-8) are addressed in this lab:
Standard 4 – Science
Key Idea 2: Many of the phenomena that we observe on Earth involve interactions among
components of air, water and land.
In this lesson students will study the relationship between rock type and the weathering
process of abrasion. The weathering process is an interaction of the three spheres that
surround the Earth, during which components of the hydrosphere and atmosphere break
down the lithosphere.
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Content:
Questions of investigation:
1. Does weathering occur at different rates for different rock types?
2. What happens to weathering over time?
Vocabulary:
Abrasion
Chemical weathering
Dissolve
Erosion
Hardness
Physical weathering
Saltation
Sediment
Solution
Stream load
Streambed
Suspension
Weathering
Materials:
Student:
Buckets for discarded water
Calculator
Electric balance
Lab packet
Nalgine bottles
Paper towels
Pencil
Shale for medium hardness rock
Sieve for sink (if used)
Water supply
Instructor:
PowerPoint presentation for intro
PowerPoint presentation for post lab
Overheads of lab packet or PowerPoint slides if possible
One empty Nalgine with known mass
Large supply of Shale pieces – pebble sized
Sieves to catch sediment in water dumped into sink.
An unweathered piece of halite and a weathered piece to put on the projector
Rounded sediments from fluvial abrasion
– Class Examples to hold up and have around the room
Initial mass of empty Nalgine bottle
Shake music (if used)
Clock or stop watch
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Procedures:
Preparation for lesson – (before class arrives)
1.
2.
3.
4.
5.
6.
7.
Make enough copies of “Shake It Up Baby” lab packet.
Prepare slide presentations for lab and post lab portions of lesson
Set up stations in the room so that there are enough for two students at a station. Each
station needs, one electric balance, one Nalgine with shale pieces, access to water
(sink or pitcher) and a few paper towels.
Put the sieves in the sink in the room.
Place a few buckets around the room so that groups that don’t have access to the
bucket can dump there excess water in to the bucket
Write on the board:
o Lesson Title
o Focus Question
Have first slide displayed with anticipatory set activity shown.
FIRST DAY – Lab activity (entire period)
Anticipatory Set (3-4 minutes as students arrive)
1.
3.
4.
5.
Have a slide shown on the screen that has river sediment shown (or if you have them
have enough actual river sediments so that each group can have some to look at their
station). On the slide write the directions: “Take a look at these sediments. Using your
observational skills, think about how they are similar and how they are different.”
Ask students to share their observations, highlighting any responses that deal with the
shape (round, angular), texture (smooth, rough) of the sediments.
Explain: “These sediments were taken from the same location, a stream near my
house”. Ask: “What are some reasons why these sediments are different?”
Explain: “In today’s lab you will explore how these sediments became that way. We
will return to this question about why they are different tomorrow once you become
experts”.
Introduction (6-10 minutes)
1.
2.
3.
Point out the title, and the focus question for today’s lab.
Tell students: You will be working in pares to explore the effects that hardness (rock
type) and length of time have on the weathering process. It is important that you find
someone that you can work with and stay on task. We need the whole period to get
this activity done.”
Read the introduction from the lab packet: “As rocks are carried along by currents in
a fast flowing stream, they tend to physically weather into smaller and smoother
pieces. Does this process occur at the same rate for different types of rocks under the
same conditions? Remember we talked about how rocks with stronger and weaker
chemical compositions weather differently. What happens to the weathering process
over time? In this investigation you will model the physical weathering process that
occurs naturally in streams. The shaking of these bottles is meant to simulate or
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4.
5.
6.
7.
8.
9.
10.
11.
model how sediments tumble, role and slide in a stream causing physical weathering
in the form of abrasion. You will speed up the process that may take years to occur in
nature.”
“Take a look at the objectives of the lab. After completing this activity you will be
able to: 1.) State the relation ship between rate of physical weathering and rock
particle hardness…what we are looking for here is, Harder rocks weather faster or
slower than soft rocks. 2.) Compare the changes to rock particles caused by abrasion
over time. What is happening to the shape and texture of the rock as weathering
continues?
There are some changes that need to be made to the lab packet so that it matches the
materials that we are using. Instead of marble we are using shale and the quartz and
halite have been done for you. Also on the graph I would like you to graph each rock
type as a separate line. I will cover this when we get done with the activity.
Explain procedure: “What do you need to do? Look at the data sheet. You see that
there is a column for weathering time, mass remaining, % mass remaining and then
and area where they want you to draw the appearance of a particle. This means you
need to know how much material you have to start out with. Since the rocks are
already in the bottle what do we need to know to get the mass of the unweathered
pieces. The mass of just the particles would be equal to the mass of the particles and
the bottle minus the mass of the bottle, which is ______grams. So you need to find
the mass of your particles and bottle and then subtract the mass of the bottle, which
I’ve measured for you out for you. This you will write in the first slot, mass
remaining at 0 minutes. All the mass is remaining since you haven’t done anything.
Take a moment to pull one of the particles out of your bottle and draw what it looks
like. You only need to do this twice even though the packet asks for it several times.
I want you to do it initially and then at the end. Focus on shape and texture, how
rough is it what is it size.
You will fill your bottle half full with water, and then as a class we are all going to
shake the bottles for 3 minutes. You will drain the water and mud from the bottle,
use your fingers to keep the rocks in, and then find the mass again.
Remember you need to subtract the mass of the bottle from your measurement each
time so make sure you have it written down, _____ grams. (Write the Initial mass
____ grams and the equation Mass Remaining = Measured Mass of particles and
bottle – mass of bottle on the board.) If your initial number isn’t between 100 and
200 grams raise your hand (they may have the balance in the wrong mode).
We will “shake it up baby” 4 times which will take something like 20 minutes so you
need to stay focused and pay attention so that we have enough time to finish the lab.
For now, only write down the mass remaining (measurement – bottle mass). Once
we are done I will give you time to calculate the % mass reaming and graph the
results on the next page.
Make sure the top is on tight, repeat shaking as directed.
Lesson Body (25 minutes)
1.
Do the shaking. Teacher should keep time – 3 minutes. Give students time to
measure mass and write it down. (If possible, it may be fun to play music during the
shaking, Shake it up baby, Shake it like a Polaroid picture etc.)
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2.
3.
4.
5.
Once students are done with shaking portion if there is still time remaining in the
period, allow them time to calculate mass remaining, % mass remaining and start
graph. The instructor should give a brief explanation of how to calculate percent
remaining (part over whole, mass remaining over initial mass).
With the graph the students will need to be walked through how to make a key and
graph multiple variables (use separate colors or symbols, dot, x or square, dashed line
solid line heavy line).
Once they have made the graph the students should start the questions.
Teacher should circulate to make sure students are on task, are properly recording
data and to answer any questions.
Second Day – Post Lab (40 minutes)
1.
2.
3.
6.
4.
Let the students come in and continue to work on the lab. (15 minutes)
Go over graph. (10 minutes) Discuss the general relationship between weathering and
time and then discuss why the different materials have different curves (hardness,
chemical composition). Have an overhead of the graph and draw the general
relationships. Explain that their curve may not be exactly the same but that they
should have the same general relationship. Weathering increases with time, the
harder a rock is the longer it will take to weather.
Go over questions. (10 minutes) Refer them to points in our previous discussions
where each topic was covered and any examples that were used to clarify. Some
topics will be covered in their notes packet and the students should be made aware of
where in the packet to look.
For closure lead a discussion about the Anticipatory Set question from the previous
day (5 minutes). “Now that you are all experts in weathering by stream abrasion…lets
go back to yesterdays question: What are some reasons why the stream sediment that I
brought in are different?” Answer: They have been weathered for different amounts of
time. They have been moved down the stream a farther distance. They have different
compositions….
Have them hand the lab in.
Student Assessment:
Each student will be required to hand in his or her own completed copy of the lab packet. Student
understanding will be assessed by the accuracy and completeness of the graph and questions in the
lab packet.
Student understanding should be monitored through out the less as teacher circulates so that students
don’t fall behind. Also the instructor to determine level of student understanding should monitor
student reposes to questions and discussion posed during class
Teacher Reflection:
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Did students enjoy the lesson? Were the students engaged by the activity? This is measured by how
well the students follow along with the activity. Did they participate when called on?
Were the objectives of the lesson met? Was the lesson effective at helping students to understand
how weathering is affected by rock type and time?
This will be measured by the responses given during class and primarily by the quality and
accuracy of individual student lab write-ups.
Did the lesson effectively use the time allotted for it?
This will be measured by the amount of material covered? Was time at the beginning of the next
class needed to complete discussions or was there enough time to begin the next activity?
Was my awareness of the students’ prior knowledge accurate?
This will be measured by the students’ ability to understand the introductory material without
further explanation. This will be apparent quality and accuracy of their responses to my questions
during the introductory review.
Were the needs of students with IEPs met?
This will be measure against each IEP student’s goals as stated in their IEP and by their
performance on the task and the quality of their products.
Resources
Bibliography of useful references
Students:
Daley, Higham and Matthias, 1986. Earth Science: A study of a changing planet. Newton , NJ:
Cebco.
Secondary Education Physical Setting Textbook designed specifically for the Earth Science
curriculum of New York State. This text has many examples that draw from localities in New
York State. This is a excellent source of information for students seeking additional
information beyond what is covered in class or in their assigned text. There are several
copies of this text available in the classroom.
Spaulding and Namowitz, 1994.
Company.
Earth Science.
Lexington, Massachusetts: D.C. Heath and
Secondary education Earth Science textbook. Each Student was assigned this text at the
beginning of the year. This text has very simple and easy to understand examples of the
processes that we will be discussing in class.
USGS: Science Topics – Weathering. Last Modified April 29th , 2005.
http://www.usgs.gov/science.php?term=1037.
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Scientific information produced by the USGS on the topics of Erosion, Weathering and
Sedimentation for student audiences. Each category provides a links to related terms,
definition and related science content. Students and teachers could use this site for further
in depth study of the topics, specifically as they relate to research at the USGS and other
research programs on the web.
Teacher:
Prothero and Schwab, 1996. Sedimentary Geology: An introduction to sedimentary rock and
Stratigraphy.
College level geology textbook, useful for in depth reading prior to the lesson. There are also
may useful diagrams and pictures available in the text.
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