Sequencing the rock layers will show students how paleontologists use fossils to give relative dates to rock strata. Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history.
These major concepts are part of the Denver Earth Science Project's "Paleontology and Dinosaurs" module written for students in grades The module is an integrated unit which addresses the following National Science Education Standards: Fossils indicate that many organisms that lived long ago are extinct. Extinction of species is common; most of the species that have lived on the earth no longer exist.
Fossils provide important evidence of how life and environmental conditions have changed. The complete "Paleontology and Dinosaurs" module takes approximately four weeks to teach. The "Who's On First?
Scientific measurements such as radiometric dating use the natural radioactivity of certain elements found in rocks to help determine their age. Scientists also use direct evidence from observations of the rock layers themselves to help determine the relative age of rock layers. Specific rock formations are indicative of a particular type of environment existing when the rock was being formed. For example, most limestones represent marine environments, whereas, sandstones with ripple marks might indicate a shoreline habitat or a riverbed.
Return to top The study and comparison of exposed rock layers or strata in various parts of the earth led scientists in the early 19th century to propose that the rock layers could be correlated from place to place. Locally, physical characteristics of rocks can be compared and correlated.
On a larger scale, even between continents, fossil evidence can help in correlating rock layers. The Law of Superposition, which states that in an undisturbed horizontal sequence of rocks, the oldest rock layers will be on the bottom, with successively younger rocks on top of these, helps geologists correlate rock layers around the world. This also means that fossils found in the lowest levels in a sequence of layered rocks represent the oldest record of life there.
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By matching partial sequences, the truly oldest layers with fossils can be worked out. By correlating fossils from various parts of the world, scientists are able to give relative ages to particular strata. This is called relative dating. Relative dating tells scientists if a rock layer is "older" or "younger" than another. This would also mean that fossils found in the deepest layer of rocks in an area would represent the oldest forms of life in that particular rock formation.
In reading earth history, these layers would be "read" from bottom to top or oldest to most recent.
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If certain fossils are typically found only in a particular rock unit and are found in many places worldwide, they may be useful as index or guide fossils in determining the age of undated strata. By using this information from rock formations in various parts of the world and correlating the studies, scientists have been able to establish the geologic time scale. This relative time scale divides the vast amount of earth history into various sections based on geological events sea encroachments, mountain-building, and depositional events , and notable biological events appearance, relative abundance, or extinction of certain life forms.
When you complete this activity, you will be able to: The first card in the sequence has "Card 1, Set A" in the lower left-hand corner and represents the bottom of the sequence. If the letters "T" and "C" represent fossils in the oldest rock layer, they are the oldest fossils, or the first fossils formed in the past for this sequence of rock layers. Now, look for a card that has either a "T" or "C" written on it. Since this card has a common letter with the first card, it must go on top of the "TC" card.
The fossils represented by the letters on this card are "younger" than the "T" or "C" fossils on the "TC" card which represents fossils in the oldest rock layer. Sequence the remaining cards by using the same process. When you finish, you should have a vertical stack of cards with the top card representing the youngest fossils of this rock sequence and the "TC" card at the bottom of the stack representing the oldest fossils.
Starting with the top card, the letters should be in order from youngest to oldest. Return to top Procedure Set B: Each card represents a particular rock layer with a collection of fossils that are found in that particular rock stratum. Mineral identification and properties using photographs by Richard Harwood of Black Hawk College — students can identify minerals photographs based on mineral property choices.
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WHO'S ON FIRST? A RELATIVE DATING ACTIVITY
Contact us if you know of a suitable replacement. Searchable mineral database by Amethyst Galleries, Inc.: Students can search for minerals by class or alphabetically. Descriptions of each mineral include physical properties, crystallography information, common uses, and chemical formulas as well as pictures. Mineral identification by Dave Jessey and Don Tarman through Cal State Pomona — students can use this site as a step-by-step tutorial to identify mineral sample.
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- Relative Dating Lab?
- INTRODUCTION.
- Relative Dating #1: EARTH SCIENCE LAB?
Igneous Rocks Igneous rock identification using photographs by Richard Harwood of Black Hawk College — students can identify igneous rock photographs based on rock property choices, self-checking. Igneous rock identification by Dave Jessey and Don Tarman through Cal State Pomona — students can use this site as a step-by-step tutorial to identify igneous rock samples.
Sedimentary Rocks Sedimentary rock identification using photographs by Richard Harwood of Black Hawk College — students can identify sedimentary rock photographs based on rock property choices, self-checking. Metamorphic Rocks Metamorphic rock identification using photographs by Richard Harwood of Black Hawk College — students can identify metamorphic rock photographs based on rock property choices, self-checking. Metamorphic rock identification by Dave Jessey and Don Tarman through Cal State Pomona — students can use this site as a step-by-step tutorial to identify metamorphic rock samples.
An interactive map where students can turn on and off features such as earthquakes, plate boundaries and names, faults, volcanoes, etc. Volcanic materials identification using photographs by Richard Harwood of Black Hawk College — students can identify volcanic material photographs based on property choices, self-checking. Volcanoes laboratory by Richard Harwood of Black Hawk College — a laboratory on volcanic processes, multiple choice and self-checking.
Deformation How do rocks respond to stress?
Relative Dating Lab
This is a 3 step investigation into deformation. In step 2, students can investigate the role of brittle vs ductile environments in relation to compressional, tensional, and shear stresses. Once the parameters are selected, an animation plays to show the impact on rock layers. Within the site you will find links so that students can learn about structural geology as well as go on virtual field trips. Question assignment could be designed to go along with field trips.
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In addition, there is a virtual mapping project. Geologic Time Interpreting geologic sections more info through Athro, Limited — students can test their knowledge of principles of geologic time through animations.
Finding Lab Activities Online
Radioactive dating game through PhET. Understand how decay and half-life work to enable radiometric dating to work. Play a game that tests your ability to match the percentage of the dating element that remains to the age of the object. Relative dating laboratory by Richard Harwood of Black Hawk College — a laboratory on relative dating, multiple choice and self-checking.
Radiometric dating laboratory by Richard Harwood of Black Hawk College — a laboratory on radiometric dating, multiple choice and self-checking. Paleontology Online rock and fossil identification kit by University of Tennessee — provides photographs and descriptions of various rocks and fossils.
Virtual museum of fossils by Valdosta State University. Topographic Maps Remote sensing laboratory by Richard Harwood of Black Hawk College — a laboratory on remote sensing, multiple choice and self-checking. Examples of landforms on topographic maps more info by Susan Slaymaker - website includes numerous example images that can be used to develop an online lab activity.
Topographic map examples more info which illustrate symbols commonly used on maps for cultural and natural features by Susan Slaymaker - website includes numerous example images that can be used to develop an online lab activity. Examples of topographic maps more info selected to illustrate common geologic processes, cultural features and topographic map symbols by Susan Slaymaker — website includes numerous example images that can be used to develop an online lab activity.
Groundwater How does groundwater move through the ground? Streams Virtual River This site may be offline. Students learn about river processes in these two activities: River Discharge and River Flooding. Coasts How do storms affect coastlines?