Lesson Plan Title. Toilet Paper Tape Measure of Geologic Time

Transcription

1 Lesson Plan Title Toilet Paper Tape Measure of Geologic Time Name (last, first): Serratos, Danielle J. Scientific Theme(s): Life Science *Changes in Life Forms over Time Earth Science *Forces that Shape the Earth *Origin and evolution of the universe and our planet Mathematic Theme: *Multiplication, division and fractions Grade Level(s): * 6-8 * 9-12 Lesson Duration: 2-3 days (approx. 3 hours). Overview The main purpose of this lesson is to show students just how small the amount of time that human civilizations have been around in comparison to Earth s history. Students seem to have difficulty understanding the scope of geologic time and this lesson allows them to see a physical representation of the time that our planet has existed. Objectives Students will be able to calculate how many millions of years are in a billion year. Students will understand the order of geologic eons, eras, and periods and the differences between them. Students will be exposed to information such as the oldest mineral, oldest rock, oldest fossil, Grade Level Expectations (GLEs) Addressed [7] SA1.1; SD1.1; SD2.2; SE3.1

2 Required Background Students must already be able to work in groups of 2-5 and stay on task without constant supervision by the teacher. This lab takes up a lot of space and requires the teacher to walk around from group to group over large distances, leaving students out of earshot of the teacher at times. Students will be expected to be familiar with what fossils, extinction, and geologic time means. Students must be able to multiply, divide and use fractions. Vocabulary Eon, Era, Period, Archean, Proterozoic, Paleozoic, Mesozoic, Cenozoic, Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Tertiary, Billion, Million Materials One roll per group of thin, poor quality toilet paper, calculators and 5 different colored gel pens (one for each of the following: numbers/years, Eons, Eras, Periods, and events) (For teacher reference) One up- to- date Geologic Time Scale: see Geological Society of America website Activity Preparation and Procedure Teachers should be familiar with the Geologic Time Scale and how to convert millions to billions and vice versa. Buy the toilet paper and gel pens if the teacher does not already have these items. Gel pens are necessary to write on the toilet paper because regular pens tear through. Teachers should be familiar with the history of how scientists age minerals, rocks, and fossils. Teachers should also understand plate tectonic theory and mass extinctions. Refer to the following resources for more information: Assessment The questions that are included in the lab worksheet are the written assessment, however, the activity itself should encourage students to ask questions about how scientists know the ages of the events along the timeline. Complementary Activities and Extension Ideas Teachers could assign the events and have students research the dates for when those events occurred, instead of being told when. This would incorporate content standards [7] SA1.1 and [7] SA2.1. References This lab was modified from Sarah Fowell, PhD at the University of Alaska Fairbanks Geology 112 Lab #1.

3 Lab: Understanding the scope of geologic time using toilet paper Name Introduction: For humans, with lives generally less than 100 years in duration and a written history that spans a mere 2,000 years, geologic time is difficult to fathom. Very little in our daily lives requires us to think in terms of millions, much less billions. Have you ever seen 1,000,000 people? 1,000,000 caribou? 1,000,000 mosquitoes? Few of us will ever posses $1,000,000 at one time. Even those who regularly deal with million and billion dollar budgets find the numbers difficult to grasp; a recent, unofficial survey indicates that the majority of U.S. congress members do not know how many million are in one billion (There are 1,000 million in a billion. That means 1,000,000,000 is one billion). Today s exercise is designed to help you envision the relative length of the various geologic eons, eras, and periods using an everyday material a roll of toilet paper. As you plot the history of the earth on your roll of 1,000 squares, try to grasp the vast expanses of time represented by simple terms like Archean or Cretaceous. A sense of the absolute is important to understanding geologic processes, because events that are rare or extremely improbable on a human time scale may be common or inevitable on a geologic time scale. Part I: Eons, Eras, Periods, and Epochs Divide into groups of 2-5. Each group should have a roll of TP, and five gel pens (black, purple, red, green, and blue). 1. Your roll of TP consists of 1,000 squares. Assume that each square represents 10 million years. How many years is represented by the entire roll? Pick a long, straight section of hallway, detach the end of the toilet paper from the roll, and lay it on the floor. This represents the top of your geologic tape measure, or the present time. As you unroll it, use the black pen to label the boundaries of the squares (= perforations) in 10 million-year increments until you get to 600 million years ago (=600 MYA). Then label every 5th perforation in 50 million-year increments until you get to 4.6 billion years ago (=BYA) and tape the end to the floor. 2. The Earth is believed to have formed 4.6 BYA. How many squares of TP will be left over when you have finished your timeline? 3. Using the geologic time scale attached to this lab, identify and label the base of the eons on your toilet paper timeline with a line and a date, using a green pen. Write the names of each eon in green within the appropriate span of TP. 4. Using a blue pen, label and date the base of the eras and record the name of each. 5. Label the periods on the time scale in purple. 6. Finally, label and draw the events in Part ll in red or pink.

4 Part II: Milestones in Earth History Below is a short list of some of the highlights of earth history. Use the approximate date to locate each event on your TP time scale. Oldest minerals (zircons): 4.2 BYA Sketch a few crystals on your time scale. Oldest rock (the Acasta gneiss): 3.9 BYA Draw a picture of a metamorphic rock Oldest fossils (bacteria): 3.5 BYA Illustrate this event with bacterial cells spheres or rods. First multicellular organisms (algae): 2.5 BYA Draw a picture of seaweed in the ocean. Oldest known ice age: 900 MYA Illustrate with ice cubes. First multicellular animals (soft-bodied Ediacaran Fauna): 630 MYA Draw a jellyfish. Their relatives were part of this fauna, and they re easier to draw than sponges! Cambrian Explosion! Trilobites and other critters with hard parts appear: 530 MYA Sketch a trilobite. Consult books available in the lab if you need visual aid. Plants colonize the land surface: 470 MYA Draw a small plant with simple branches and no leaves. First fish with jaws: 410 MYA Illustrate with a fish. First land-dwelling vertebrates (= amphibians): 363 MYA Sketch a salamander. Formation of the supercontinent Pangea: 260 MYA An illustration of a globe with one giant land mass will do. Largest mass extinction in Earth s history: 251 MYA How about a skull and crossbones? First dinosaurs and mammals: 230 MYA Sketch your favorite dinosaur. First birds: 160 MYA Draw a bird. First flowering plants: 130 MYA Illustrate with a flower. Mass extinction of non-avian dinosaurs and ammonoids (squids with shells): 65.5 MYA Sketch another dinosaur with a red x symbol over it. First members of the genus Homo (our relatives!): 300,000 years ago (= 0.3 MYA) A more upright stick figure, please. Last ice age: 20,000 years ago (= 0.02 MYA) Sketch some more ice cubes here. Roman empire at its height: 2,000 years ago (= MYA) Sketch the Roman coliseum (you know, where gladiators fought).

5 Part III: Deep Time and the Big Picture Take a walk through your time scale and use it to answer the questions below. 1. Look at your geologic tape measure. What can you say about the relative lengths of the Archean, Proterozoic, and Phanerozoic eons? 3. Based on the events included in your time scale, what criteria did geologists use to determine/ recognize the boundaries of the Paleozoic, Mesozoic, and Cenozoic eras? 4. Find the events on your timescale related to the appearance and extinction of dinosaurs. Compare this to the length of time that humans (including all members of our genus, Homo) have walked the Earth. If success is equivalent to longevity, dinosaurs have us beat (for now). Human history to date represents what fraction of the non-avian dinosaurs rule? Show your work. A. Amount of time that non-avian dinosaurs were alive and well on Earth: MY B. Amount of time that has passed since our genus (Homo) evolved: MY C. Now express these numbers as a fraction (non-avian dinosaurs over humans): D. These are BIG numbers, so let s turn your fraction into something easier to grasp by reducing it. Divide both numbers (the numerator on the top and the denominator on the bottom) by the denominator. Use a calculator! = You should end with a large number in the numerator and 1 in the denominator, giving you the answer to the following question: How many times longer did the non-avian dinosaurs survive, compared to our (ongoing) lifespan as a group?

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