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Geologic time scale and relative dating lab

At the end of this geologic time scale lesson plan, students will be able to describe how the relative and absolute age of rocks and fossil record provide evidence of Earth’s geologic history, discover how the Earth’s geologic history is classified, and give examples of major events in the Earth’s geologic history. Each lesson is designed using the 5E method of instruction to ensure maximum comprehension by the students.

The following post will walk you through each of the steps and activities from the geologic time scale lesson plan.

At the beginning of the lesson, the class will do a Think-Pair-Share to discuss the objective.

The teacher can model this activity first. You can do it with the class or prepare it prior to class. Cut off 2-3 feet of receipt tape. Length doesn’t really matter. On one end put “birth” and the other “today.” Divide the tape into increments of years (ones, fives, or tens). Depends on your age. Define “chronological time” for students. Draw pictures related to important events in your life in the correct place on the timeline. Now have the students make a timeline of their lives. Have them add up important events with pictures. Make sure they put them in chronological order. Tell students they will be learning about the geological timescale of the age of the Earth and how scientists determined it. Explain the difference between geological time and historical time.

The teacher will help to clear up any misconceptions about the geologic time scale. A major misconception is that students probably think people and dinosaurs lived at the same time.

Estimated Class Time for the Engagement: 20-30 minutes

This student-centered station lab is set up so students can begin to explore geologic time scale. Four of the stations are considered input stations where students are learning new information about the geologic time scale and four of the stations are output stations where students will be demonstrating their mastery of the input stations. Each of the stations is differentiated to challenge students using a different learning style. You can read more about how I set up the station labs here.

Students will be working in pairs to better understand the geologic time scale. Students will be examining a number models of different layers of the earth. From the models, students will make observations as to which layer is older, younger, and which fossils are older/younger. Students will record their observations on their lab sheet.

At this station, students will be watching a short video explaining the laws of relative rock dating. Students will then answer questions related to the video and record their answers on their lab station sheet. For example: What is the law of superposition? What is the law of crosscutting? What is the law of inclusion?

The research station will allow students to find out information about the history of the Earth. Students will be able to click on sections of a clock that is used to represent different time periods that occurred on Earth. Students will be instructed to complete a few tasks and record answers on their lab sheets.

This station will provide students with a one page reading about how old rocks are. Students will read about relative and absolute dating, as well as superposition. These are what scientists consider when dating rocks. There are 4 follow-up questions that the students will answer to show reading comprehension of the subject.

The assess it station is where students will go to prove mastery over the concepts they learned in the lab. The questions are set up in a standardized format with multiple choice answers. Some questions include: Which fossil would make the best index fossil? Which law of relative dating is the student referring to? Which statement is incorrect about the Geologic Time Scale? Which era best represents when humans first appeared on Earth?

Students who can answer open-ended questions about the lab truly understand the concepts that are being taught. At this station, the students will be answering three task cards: How do geologists use index fossils to determine the age of rock strata? What is the difference between relative dating and absolute dating? Briefly, describe the geologic time scale.

Your visual students will love this station. Students will sketch three images to explain the laws of relative rock dating.

The organize it station allows your students to organize the type of relative dating to descriptions that match.

Estimated Class Time for the Exploration: 1-2, 45 minute class periods

The explanation activities will become much more engaging for the class once they have completed the exploration station lab. During the explanation piece, the teacher will be clearing up any misconceptions about geologic time scale with an interactive PowerPoint, anchor charts, and interactive notebook activities. The geologic time scale lesson includes a PowerPoint with activities scattered throughout to keep the students engaged.

The students will also be interacting with their journals using INB templates for the geologic time scale. Each INB activity is designed to help students compartmentalize information for a greater understanding of the concept. The geologic time scale INB templates allow students to focus their notes on the Geologic Time Eras.

Estimated Class Time for the Exploration: 2-3, 45 minute class periods

The elaboration section of the 5E method of instruction is intended to give students choice on how they can prove mastery of the concept. When students are given choice the ‘buy-in’ is much greater than when the teacher tells them the project they will have to create. The elaboration project will allow students to create a presentation to teach about geologic time scale. Estimated Class Time for the Elaboration: 2-3, 45 minute class periods (can also be used as an at-home project)

The final piece of the 5E model is to evaluate student comprehension. Included in every 5E lesson is a homework assignment, assessment, and modified assessment. Research has shown that homework needs to be meaningful and applicable to real-world activities in order to be effective. When possible, I like to give open-ended assessments to truly gauge the student’s comprehension.

Estimated Class Time for the Elaboration: 1, 45 minute class period

The full lesson is available for download from my TpT store. Save yourself a ton of time and grab it now.

In this lab-learning exercise you will:

Use the theory of radioactive isotope decay to calculate parent and daughter isotope abundances and determine the absolute age of geological materials. Determine relative geologic age sequences using the basic principles of relative age determination. Distinguish different types of unconformities in the stratigraphy of the Grand Canyon.

There are two parts to this lab exercise A. Part 1 is on absolute age determinations using radioactive isotopes and their daughter products in geological materials.

In Part 2 you will use the principles of relative dating to determine sequences of geological events as indicated by the layers and structures in the rocks. Part 2 ends with an application of the principles of relative dating to the rocks of the Grand Canyon.

PART 1: DETERMINING ABSOLUTE GEOLOGIC AGES
Go to the Virtual Dating Web page and earn your Virtual Radiochronologist Certificate by completing the exercise entitled Virtual Dating Isochron for rocks and minerals. E-mail a copy of your certificate to the Assignments folder in the virtual classroom, or else mail in a hard copy, or both.

Note on Carbon-14: Table 8.1 in Chapter 8 of your textbook (third edition) lists some radiometric decay schemes. Add one more: Carbon-14 decays to Nitrogen-14 with a half-life of 5,730 years.

With such a geologically short half life, carbon-14 can only be used to determine ages of relatively young materials, less than 70,000 years old. Older materials have so little carbon-14 left that it cannot be accurately measured. Thus, carbon-14 is of no use in determining the absolute ages of, for example, dinosaur fossils.

The only materials that start out with usable amounts of carbon-14 in them are carbon-bearing materials which derived their carbon immediately from the atmosphere or from shallow water. This means that the remains of living things are useful for carbon-14 dating. Most rocks, however, are not useful for carbon-14 dating (either not enough carbon, or didn’t derive its carbon from the atmosphere-shallow water reservoir).

PART 2: DETERMINING RELATIVE GEOLOGIC AGE SEQUENCES – This has two parts, A and B.

A. Borrowed from Pam Gore and Georgia Perimeter College.
We are going to borrow a set of Relative Dating Exercises from Pamela Gore of of Georgia Perimeter College. Print out the
Relative Dating Lab Exercises
( http://gpc. edu/

Before you perform the Relative Dating Lab Exercises you should read the following Web pageFor background explanations and illustrations: Relative Dating Laboratory background
( http://www. dc. peachnet. edu/

REMEMBER – Print out and complete questions 1-15 of the Relative Dating Lab Exercises.

You can either print out and mail a copy of your marked-up exercise Part A from Dr. Reynolds, to:

Ralph Dawes-ESS
Wenatchee Valley College
1300 Fifth Street
Wenatchee, WA 98801

Remember to put your name on your exercise pages, not just the outside of the envelope.

B. Applying the Principles of Relative Dating to a Real Case: The Grand Canyon Sequence

This particular exercise was created by Al Friedman of Everett Community College.

View the above image, a cross-section (side-view of a cut-out through the crust) of the Grand Canyon. Study this diagram carefully, noting the orientation of individual rock layers, as well as the type of rock in each layer, and the age of the rock in each layer. Refer to the geologic time scale on page 219 for the names of each of the geologic time periods, as well as the absolute dates attached to each Period.

In order to answer the following questions, you will need additional geologic information about the Grand Canyon.

YOUR GOAL IN PART 2.B. IS TO CLEARLY IDENTIFY FOUR MAJOR UNCONFORMITIES IN THE GRAND CANYON SEQUENCE. Four major unconformities are evident in the Grand Canyon cross-section. Remember that unconformities represent sections of missing time, either through non-deposition of rocks for a period of time, or through an interval of erosion which has removed some strata. (Strata are layers of rock.)

The three different types of unconformities are shown in the textbook (refer to the index of the book to find where). Each of the four major unconformities in the Grand Canyon can be identified as one of the three specific types of unconformities. For each of the four major unconformities in the Grand Canyon, answer each of the following questions:

For the oldest unconformity:

1. Between which two rock layers (use the names of the rock layers shown on the diagram) does the unconformity occur? It occurs between the Proterozoic Vishnu Schist and Proterozoic Bass Limestone.

2. What evidence do you specifically see that allowed you to identify an unconformity at this location?
Schist forms deep in the crust and must be uplifted and eroded to have the sediments that form limestone deposited on top.

3. Which of the three types of unconformities is this? It is a nonconformity.

4. In the sequence of geological eons, eras, or periods, where is the unconformity located? (Be as specific as you can, such as “between the Jurassic and Tertiary periods,” or “Within the Triassic period.”)
This unconformity is in the Proterozoic Eon.

For the next-to-oldest unconformity:

5. Between which two rock layers (use the names of the rock layers shown on the diagram) does the unconformity occur?
6. What evidence do you specifically see that allowed you to identify an unconformity at this location?
7. Which of the three types of unconformities is this?
8. In the sequence of geological eons, eras, or periods, where is the unconformity located? (Be as specific as you can, such as “between the Jurassic and Tertiary periods,” or “Within the Triassic period.”)

For the next-to-youngest unconformity:

9. Between which two rock layers (use the names of the rock layers shown on the diagram) does the unconformity occur?
10. What evidence do you specifically see that allowed you to identify an unconformity at this location?
11. Which of the three types of unconformities is this?
12. In the sequence of geological eons, eras, or periods, where is the unconformity located? (Be as specific as you can, such as “between the Jurassic and Tertiary periods,” or “Within the Triassic period.”)

For the youngest unconformity:

13. Between which two rock layers (use the names of the rock layers shown on the diagram) does the unconformity occur?
14. What evidence do you specifically see that allowed you to identify an unconformity at this location?
15. Which of the three types of unconformities is this?
16. In the sequence of geological eons, eras, or periods, where is the unconformity located? (Be as specific as you can, such as “between the Jurassic and Tertiary periods,” or “Within the Triassic period.”)

When you are done, you should have answered questions 1 through 4 four times, one for each major Grand Canyon unconformity. Note that the first four answers are already given to you.

Enter your answers into the Lab 3B.2 online “Quiz” form. Remember to do so by the end of the Week, and click “Submit” when you are done.

    Lab 3A: Turn in your Virtual Geochronologist Certificate. Lab 3B Part 1: Turn in your marked-up and written-answered printout of Pam Gore’s Relative Dating Lab exercises. Lab 3B Part 2: Turn in your written answers using the online Lab 3B.2 “quiz.”

That’s it. You are now absolutely and relatively up to date!

Dr. Ralph Dawes, WAOL Earth Systems Science Instructor

Ralph Dawes-ESS
Wenatchee Valley College
1300 Fifth Street
Wenatchee, WA 98801

Remember to put your name on your exercise pages, not just the outside of the envelope.

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