Lesson Plan

Rocks

up-close investigation of rocks

NPS photo

Overall Rating

Add your review
Grade Level:
Second Grade
Subject:
Earth Science
Duration:
30 minutes
National/State Standards:
Utah Integrated Core Curruculum Topic, Standard Three: Students will develop an understanding of their environment. Objective Three: Investigate the properties and the uses of rocks.
Keywords:
sedimentary rocks, stone tools, erosion, minerals, Biological Soil Crust, deposition

Overview

Students explore a few rocks and minerals of the area. They investigate how sandstone was formed and experiment with erosion to demonstrate how local landforms are the result of sand and rock being removed. Students explore biological soil crust, and search for clues to discover how we use rocks compared to the people who lived here in ancient times.

Objective(s)

PRE-TRIP ACTIVITY
Just What Are Rocks Anyway?
Students will be able to:
a. Understand that rock underlies everything on the surface of the earth.
b. Name one set of categories that can be used to classify a rock collection.

STATION #1
Rocks, Rocks and More Rocks

Students will be able to:
a. Identify and describe, using observable characteristics, three specific kinds of rocks
found in the area.

STATION #2
Build Up, Tear Down

Students will be able to:
a. Name two processes that change rocks.
b. Name two things that harden rocks.
c. Name two things that erode rocks.

STATION #3
Secrets in the Soil

Students will be able to:
a. Explain two roles of biological soil crusts.
b. Name two places to walk in order to avoid stepping on biological soil crusts.

STATION #4
Rocks: Past and Present

Students will be able to:
a. Name two modern uses of rocks.
b. Describe how people used to use rocks.

POST-TRIP ACTIVITY
Rock Art

Students will be able to:
a. Describe two things about a rock that could easily be missed.
b. Name one use for a rock.

Background

Rocks are made up of one or more minerals. Minerals are naturally occurring elements e.g., gold) or inorganic compounds (e.g., quartz) that have specific crystal structures.

There are three major kinds of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from molten rock (magma) that has cooled. Examples include granite, basalt and pumice. They are usually unlayered (except basalts) and often contain visible crystals. Sedimentary rocks form when sediments that are deposited by water or wind on the surface of the earth, harden and solidify over time, as they are buried by more sediment. Sedimentary rocks commonly look layered. Metamorphic rocks are rocks of any type that have been altered (not melted) by heat or pressure. Sandstone metamorphoses into quartzite, limestone into marble, and granite into gneiss. Crystals commonly seen in metamorphic rocks are usually oriented in lines or sheets, at times giving both small hand samples and outcrops a wavy or crinkled appearance.

Rocks change. Heat or pressure can metamorphose any type of rock. If a rock is heated to the melting point and later recrystallizes, a new igneous rock can form. Any type of rock can erode, be redeposited, and become a sedimentary rock. These processes, changing one type of rock into another, are known collectively as the rock cycle. Many simpler cycles exist within the complex rock cycle. Metamorphic rocks maybe remetamorphosed. Igneous rocks may melt and recrystallize.

Most rocks in southeastern Utah are sedimentary, and the most common sedimentary rock is sandstone. Sandstone is made up of quartz sand grains cemented together by calcium carbonate or silica. The red appearance of many types of sandstone in the area is due to oxidized iron that coats the sand grains. Generally, sandstone is easily eroded. Water is the most effective agent of erosion, but gravity and wind also play a part. The erosion of sandstone formed the unique canyons, needles, arches, natural bridges, spires, and balanced rocks of southeastern Utah.

Petrified wood forms when minerals (usually quartz) replace organic materials in wood. Chert is microcrystalline quartz, without the cellular structure visible in petrified wood. It is very hard and breaks conchoidally. Limestone is calcium carbonate deposited on ocean floors.

Granite is found in the La Sal Mountains near Arches and Canyonlands national parks. It is a hard igneous rock that cooled from magma while still underground. Granite is composed primarily of visible crystals of quartz, mica, and feldspar. Generally, granite erodes more slowly than sandstone. Small pebbles eroded from granite, along with organic materials
from mountain vegetation, contribute to rich mountain soil.

Deserts have less, smaller, and slower-growing vegetation than mountains, so desert soils have a low organic content. Biological soil crusts are extremely common in the southeastern Utah high desert and help to make up for this lack of organic matter. The soil crusts are a community of small organisms that form a living mat and secure the top few inches of sand particles against water and wind erosion. The crusts also increase absorption and retention of water and add nitrogen to the soil, an essential for plant growth. Biological soil crusts give desert soils a lumpy, spongy look, a result of gases produced by each living, breathing community member.

Because of their incredible importance and extreme fragility, the preservation of biological soil crusts is the target of many educational eff orts within the southeastern Utah national parks. To avoid walking on the crusts, hikers should walk on slickrock, on trails, or in washes. Don’t bust the crust!

Procedure

Extensions

PRE-TRIP ACTIVITY
Just What Are Rocks Anyway?


Have students start a rock collection from rocks found in the schoolyard. Have students categorize the collected rocks by observable characteristics.

STATION #3
Secrets in the Soil 


Have students imagine they were shrunk to a size smaller than an ant. Have them write a story or draw a picture of their adventures exploring the pothole garden or crypto condo.

Additional Resources

Baylor, B. (1974). Everybody needs a rock. Illus. by P. Parnall. New York, NY: Macmillan
Publishing.

Bramwell, M. (1983). Understanding & collecting rocks & fossils. London, England: Usborne
Publishing.

Caduto, M. & Bruchac, J. (1988). Keepers of the earth: Native American stories and environmental activities for children. Golden, CO: Fulcrum.

Cole, J. (1987). The magic school bus: Inside the earth. Illustrated by B. Degen. New York, NY: Scholastic.

Gans, R. (1984). Rock collecting. Illustrated by H. Keller. New York, NY: HarperCollins
Publishers.

Hyler, N. W. (1987). The how and why wonder book of rocks and minerals. Los Angeles, CA: Price, Stern, Sloan Publishers.

Williams, D. (1997). Geology: Arches National Park. Moab, UT: Canyonlands Natural History Association. Brochure.

Williams, D. (2000). A naturalist’s guide to canyon country. Helena, MT: Falcon Publishing.