Prepare trays with each of the nine rock samples. Each sample should be assigned a number. Students will use these numbers when identifying the rocks. Each group of students will receive a tray when doing the lab. The day before the lab, students should read the article “Rocks Serve as Snapshot of Valley’s Timeline” by Jill S. Schneiderman for homework. When reading the article, they should underline or highlight any rock name they encounter.
- To get students thinking about where rocks come from, ask: “How did your backyard get its rocks?”
- Ask the students what kind of rocks they have in their backyard, focusing particularly on the rocks’ physical characteristics, and whether any of the students have outcrops or unusual specimens.
- Divide the class into small groups. Give each group a few minutes to brainstorm a potential “history” of how a rock, chosen from the examples given by the students or one of their own backyards, may have gotten into his/her backyard.
- At the conclusion, relate the exercise to how the Hudson Valley’s geologic past has shaped and influence the rocks that can be found across the local landscape today.
Students should break up into pairs for this exercise; however, each person should complete and hand in their own lab packet.
- Distribute materials to the students, including their lab sheets, maps, and reference tables. Provide each group with a tray containing the nine unidentified rock samples.
- Explain that each of the samples was found somewhere in the Hudson Valley and it is up to the students to explain why the rocks are the way they are and locate where they came from. Stress the importance of using the reference materials provided, their Earth Science Reference Tables, and the article they read for homework when doing the activity.
- Once students answer all lab questions and identify each sample they should check their results with the teacher. If a student misidentifies a rock sample they should be made aware of which ones are incorrect and have a chance to correct their error.
Often timeswe don’t think about the rocks we see around us everyday as we walk around our property, drive down roads, or hike up hills and mountains. Why are there different rocks in different places? How did the rocks come to be as they are? Very little attention is paid to the geologic tapestry of an area aside form the most basic physical characteristics of the rocks we encounter. Geologists have learned to see rocks as more that just something colored and clunky. They have learned to interpret the past from the stones they see under their feet in the present. They ask the question, “What happened to make this rock the way it is?” By noting simple physical features, along with considering a rock’s mineral make-up, a geologist can decipher the geologic events and processes that occurred to form and mold the rocks all around us and in our backyards.
In the Hudson Valley a scientist can hold rocks spanning the three major types—metamorphic, igneous, and sedimentary—and from a range of geologic time periods all in a single day trip up or down the valley. Each different kind of rock tells a tale of molten magma, being squeezed by continents, thrust up as part of a mountain, or buried beneath a shallow inland sea swarming with exotic creatures. From these simple rocks, we can learn about our natural history—not only how the rocks came to be, but how the Hudson Valley came to be as well.
Students could pick a region of New York State and do a research project that includes information about the different rocks and rock types found there, why those specific rocks are found in that region, and what the commercial uses of some of the named rocks are. Students would then present their results to the class either as a poster presentation or a PowerPoint. The New Paltz worksheet and answer keys are provided as an example of an extension activity.
As an exit ticket challenge, hold up different rock samples and ask students to answer where the rocks could be found, and why.