Primary Type: Lesson Plan
Status: Published
This is a resource from CPALMS (www.cpalms.org) where all educators go for bright ideas!
Resource ID#: 72026
Sweet Superposition!
This lesson addresses only the Law of Superposition portion and not radiometric dating. Students will investigate the correlation between rock layers
and fossil age. Students will also become familiar with the Law of Superposition and apply to finding the relative age of excavated "fossils".
Subject(s): Science
Grade Level(s): 7
Intended Audience: Educators
Instructional Time: 1 Hour(s)
Resource supports reading in content area: Yes
Freely Available: Yes
Keywords: Superposition, Relative Dating, Law of Superposition
Resource Collection: FCR-STEMLearn Earth Systems
ATTACHMENTS
Stratification Bisection.docx
Superposition Quiz.docx
SUPERPOSITION TRAYS.docx
Sweet Superposition.docx
LESSON CONTENT
Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
Students will be able to define the Law of Superposition.
Students will be able to organize fossils by their relative ages using the Law of Superposition.
Prior Knowledge: What prior knowledge should students have for this lesson?
Students should have mastered 4th grade standard SC.4.E.6.1: Identify the three categories of rocks: igneous, (formed from molten rock); sedimentary (pieces of
other rocks and fossilized organisms); and metamorphic (formed from heat and pressure).
Students should already know that sedimentary rocks can be found in layers.
Students should also know what a fossil is and that paleontologists search for them in order to give us clues about Earth's past.
Guiding Questions: What are the guiding questions for this lesson?
Before inquiry lab (Step of Teaching Phase):
1. What is a scenario in your life where it would be important to know the exact date events happened? (Daily Bell Schedule, Timelines, TV Showtimes)
2. When would it be more helpful to only know the order in which events happened? (Recipe instructions, Turn-by-turn directions)
3. How can we tell the age of a discovered fossil? (Superposition and radiometric dating)
After inquiry lab (Step 4 of Teaching Phase):
1. The Law of Superposition states that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom, each layer
being younger than the one beneath it and older than the one above. How might this law help you to find the relative age of the fossils you unearthed? (Students
should correlate the relative age of their "fossils" to the age of the rock layers using the Law of Superposition. You may want to target specific students' responses
page 1 of 3 to the "why" questions from before to guide the rest of the class toward understanding the link between ages of layers of rock and the age of the fossils found
within them.)
2. Which layer would be oldest if several layers of rock have a layer disrupting them or "breaking them apart"? (Show this picture) (Explain to students that the layer
below must be older. Those layers must already be in place in order for a new layer to disrupt them.)
3. How might it be possible to find a fossil embedded in a layer of rock that is not relatively the same age as that rock? (Rock layers being disturbed/dug up, fossils
being uplifted in rock. NOTE: These occurrences are less common.)
Teaching Phase: How will the teacher present the concept or skill to students?
Step 1: To begin the lesson, conduct a K-W-L as described in the Formative Assessment section.
Step 2: Pose the following discussions:
What is a scenario in your life where it would important to know the exact date events happened? (Daily Bell Schedule, Timelines, TV Showtimes)
When would it be more helpful to only know the order in which events happened? (Recipe instructions, Turn-by-turn directions)
How can we tell the age of a discovered fossil? (Superposition and radiometric dating)
Step 3: Refer to Guided Practice Section.
Step 4: Following the Sweet Superposition lab, teacher will lead a discussion based on the questions on the back of the students' lab sheets. Teacher will elicit
student responses and guide the discussion toward understanding that the Law of Superposition tells us that not only can rocks be relatively dated by their layers, but
also fossils within those rock layers.
1. Looking at your "fossils", which fossil would you hypothesize is oldest? Why? (Students should identify samples taken from the pebble layer as oldest. Leave their
"why" answers open-ended until we summarize.)
2. Which fossil do you hypothesize is youngest? Why? (Students should identify samples taken from the soil layer as youngest. Leave their "why" answers open-ended
until we summarize.)
3. Are there any fossils that you infer to be around the same age? How can you tell? (Students should identify any samples taken from the same layer as each other to
be similar in age. Leave their "why" answers open-ended until we summarize)
4. The Law of Superposition states that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest is on bottom, each layer
being younger than the one beneath it and older than the one above. How might this law help you to find the relative age of the fossils you unearthed? (Students
should correlate the relative age of their "fossils" to the age of the rock layers using the Law of Superposition. You may want to target specific students' responses
to the "why" questions from before to guide the rest of the class toward understanding the link between ages of layers of rock and the age of the fossils found
within them.)
5. Which layer would be oldest if several layers of rock have a layer disrupting them or "breaking them apart"? (Show this picture) (Explain to students that the layer
below must be older. Those layers have to already be in place in order for a new layer to disrupt them.)
6. How might it be possible to find a fossil embedded in a layer of rock that is not relatively the same age as that rock? (Rock layers being disturbed/dug up, fossils
being uplifted in rock. NOTE: These occurrences are less common.)
Step 5: Refer to Independent Practice section.
Guided Practice: What activities or exercises will the students complete with teacher guidance?
Step 3: Before class, set up superposition trays filled with pebbles, sand and soil as shown in this diagram.
Bury candy (can substitute with replica fossils or figurines) throughout the various layers for students to "excavate".
Be sure to distribute candy across the stratified layers so that each tray has at least one example of "fossils" coming from the same layer and fossils coming from
earlier/later layers.
Be sure to review your class lab safety procedures with the students. Students should wear eye protection at all times while participating in the inquiry lab.
As students are excavating, they will record their observations/findings on this worksheet.
The worksheet includes discussion questions that they may answer as a small group. These questions will be reviewed as a whole group during Step 4 found in
the Teaching Phase.
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the
lesson?
Step 5: Students will now apply their knowledge of the Law of Superposition as they complete this worksheet on superposition taken from the Lake County Forest
Preserves website. (Note: The worksheet is labeled Fun With Stratigraphy. You may want to explain to your students that "stratigraphy" is the branch of geology that
studies the order and position of rock layers. Upon completion of the worksheet, they can all be called amateur "stratigraphers"!)
As the students work, the teacher will circulate to ensure that students are properly identifying the relative age of fossils according to their depth within the layers.
Be sure to correct student misconceptions that disrupted layers become older or younger based on anything bisecting them. (i.e. just because you dig a hole
through several layers of rock, the bottom of your hole is NOT older than the layers of rock it has bisected.)
Once all students have completed the worksheet, review the answers to the worksheet as a whole group. The answer key can be found immediately following the
worksheet.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
After reviewing the answers to the independent practice worksheet, review with students the definition of the Law of Superposition.
Reiterate that the oldest layers of rock will always be found on bottom and youngest on top.
Remind students that any rock layer that disturbs (bisects) other rock layers MUST be newer than the layers it has disrupted.
Students will take this quiz before exiting. The teacher may opt to collect student response via iClickers, SMART Response remotes or through internet-enabled
smart phones/tablets for easier data collection and analysis. See "Summative Assessment" section for further details.
Summative Assessment
Once students have completed their Independent Practice worksheet and the class has reviewed the answers for clarification, students will be assessed through a
short multiple choice mini-quiz to evaluate their mastery of the Law of Superposition. The results of this quiz should be reviewed by the teacher to ensure mastery of
the Law of Superposition. For those students who have not demonstrated mastery, consider the Sand Art activity described in the Accommodations section. For
students who have shown mastery, consider the Extension activity. All students will end the lesson by finishing the "L" portion of their KWL (see Formative Assessment
for description).
Formative Assessment
Together with the students, begin the lesson by constructing a K-W-L of prior knowledge relating to how we find the age of rocks and fossils. Give each student a KWL
page 2 of 3 worksheet and allow them 3-4 minutes to fill out the "What I Know" (K) and "What I Want to Know" (W) portions of the KWL. "What I Learned" (L) will be completed at
the end of the lesson. Once the students have completed the K and W sections of their KWL, bring the class together for a whole group discussion, assembling a
master list of "K" and "W" student responses on the board. Explain to students that you will be revisiting the "L" at the end of the lesson. Have students place this
worksheet in a safe place to be completed later.
Feedback to Students
Following a hands-on inquiry activity and discussion, students will complete this worksheet on superposition. (Note: The worksheet is labeled Fun With Stratigraphy.
You may want to explain to your students that "stratigraphy" is the branch of geology that studies the order and position of rock layers. Upon completion of the
worksheet, they can all be called amateur "stratigraphers"!) As the students work, the teacher will circulate to ensure that students are properly identifying the relative
age of fossils according to their depth within the layers. Be sure to correct student misconceptions that disrupted layers become older or younger based on anything
bisecting them. (i.e. just because you dig a hole through several layers of rock, the bottom of your hole is NOT older than the layers of rock it has bisected.)
ACCOMMODATIONS & RECOMMENDATIONS
Accommodations:
For differentiated learning, you may consider creating sand art sculptures with your students. Have students take turns filling the sculptures with various colors of
sand, then ask them which layer they added first (oldest layer) and which they added most recently (youngest). If the container is large enough to add foreign objects
(beans, glass stones, macaroni pieces) you can have them pretend they are fossils and talk about which fossil is oldest and youngest based on what order you placed
them in the container.
Extensions:
For high achieving students, you may choose to forgo (or supplement) the multiple choice quiz as a summative assessment in favor of a more independent activity. For
example, have the students recreate a cliff face with exposed stratified rock. Tell them to draw fossils into multiple layers and include a legend. Then have them
create a "quiz" that asks at least 5 questions addressing the relative ages of various fossils in their pictures with respect to each other (essentially, creating their own
unique version of the worksheet).
Special Materials Needed:
Materials Needed for Inquiry Lab:
Teacher Computer/Printer to print off worksheets
Superposition Pans - (Instructions included in attachment)
Pebbles/Small stone
Sand
Soil
Hard individually-wrapped candies (it is SWEET Superposition after all!) Optional substitutes: Figurines, dry beans, coins, replica fossils
Optional Materials:
Sand Art kits (for differentiated activity)
Dry Beans, Uncooked Macaroni, beads, glass stones (Optional for differentiated activity. See description above.)
Construction paper and drawing supplies (for Extension activity)
SOURCE AND ACCESS INFORMATION
Contributed by: Adam Fournier
Name of Author/Source: Adam Fournier
District/Organization of Contributor(s): Alachua
Is this Resource freely Available? Yes
Access Privileges: Public
License: CPALMS License - no distribution - non commercial
Related Standards
Name
SC.7.E.6.3:
Description
Identify current methods for measuring the age of Earth and its parts, including the law of superposition and
radioactive dating.
Related Access Points
Access Point Number
SC.7.E.6.In.3:
Access Point Title
Demonstrate how older rock layers are deposited at the bottom before younger layers (Law of Superposition).
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