Earth History – Middle School

Big Idea: Earth History emphasizes the use of knowledge and evidence to construct explanations about the processes and systems that have operated over geological time.

Sub Concept 1: Use of processes of observation and inference contribute to answering questions by students and those asked by geologists.

Inference: Part 1

Investigate canceled envelopes and list observations and inferences to determine a historical sequence of events.

Inference: Part 2

Trading envelopes students use inferential thinking to develop a sequential history.

Sub Concept 2: Use videos, photographs, rock samples, and multimedia to introduce a local site (example, Red Bud Valley)

Part 1: Who was the first explorer to come to this area?

Part 2: Visit the site and look at points of interest, and do a geology lab inspection of four rocks.

Part 3: Students generate questions about the site and refine them in collaborative groups. The questions should inquire into the origin, structure, age, and composition of the site.

Part 4: Organize questions by establishing categories for different types of questions.

Sub Concept 3:Students begin to build the concept of rock layers as a three dimensional structure that comprises many layers.

Part 1: Observe and compare rock samples from two locations at your site as an introduction to sedimentary rocks (limestone, sandstone, and shale). Use acid to test for calcium carbonate.

Part 2: Correlate rocks from the two sites and begin to visualize the layers.

Part 3: Compare rock samples from several locations and begin to build a view of the sequence of sedimentary rocks.

Part 4: Look for evidence of differential erosion and explore rocks.

Sub Concept 4:Investigate the properties of sand, sandstone, and shale and the process that creates them.

Part 1: Consider how long the rocks have been there.

Part 2: Compare sand samples from different locations (mountains, beach, sand dunes) and relate features of the sand to the process that created it.

Part 3: Observe erosion and deposition using a stream table, then discuss how variables affect the system.

Part 4: Compare the processes of physical weathering, chemical weathering, and erosion.

Part 5: Make sandstone using a variety of sands and sodium silicate as the matrix or glue. Introduce basins as low areas where sediments might accumulate over time.

Part 6: Compare sandstone to shale to determine the products in shale. Use clay and sediment to make shale and discuss the principles of original horizontality and uniformitarianism.

Sub Concept 5: Investigate conditions that lead to the formation of sedimentary rock, limestone, and how rock layers provide the evidence for ancient environments.

Part 1: Study formation of limestone layers. Knowing that limestone formed in a marine environment, search for the source of calcium carbonate in the limestone by modeling chemical reactions in a seawater environment.

Part 2: Test a number of items from the ocean to see if they contain calcium carbonate, including the precipitate resulting from animals respiring in seawater (limewater).

Part 3: Determine the ingredients in limestone and create a recipe for making this rock. Make limestone and add it to the sandstone layer in their basin. Look at the age of layers and the principle of superposition.

Part 4: Considering modern environments that might provide clues to past environments by using evidence about fossils and sedimentary rocks, interpret the sequence of environments over time.

Sub Concept 6: Become familiar with geological time (enormous spans of time) and scale and put the history of your site into the scale.

Part 1: Create a personal timeline to record their own history using eras and divide their history into eras.

Part 2: Mark off 10 important events in the history of the earth from the formation of the planet 4.5 bya to the present. Make a scale for the timeline.

Part 3: Construct the timeline using adding machine tape.

Part 4: Add the history of your site to the timeline and discover gaps in the layers of rocks.

Sub Concept 7: Research index fossils as evidence for determining the relative age of sedimentary rocks and then explore fossil succession over geologic time.

Part 1: Study index fossils (an organism that lived for a relatively short time in many places around the world) found in three locations at your site and then correlate rock layers.

Part 2: Sequence thirty major events in the history of the earth (geological and biological).

Sub Concept 8: Look at two other types of rocks found on earth, igneous and metamorphic, and the processes that form these rocks.

Part 1: Use reference material to identify a number of igneous and metamorphic rock (each type forms from a different rock source) samples. Review the rock cycle.

Part 2: Experiment with salol crystals to determine the effect of cooling rate on crystal size.

Part 3: Investigate some more local rocks using knowledge and techniques learned.

Part 4: Design and conduct students own geology project.

Submitted by Mary Stewart