Soils Overview

Science

Grade 2

Unit 1

SOILS

(based on STC Kit)

INTRODUCTION

Soils can easily be described by their color, texture and capacity to retain water. Understanding soils helps us to also understand how the growth of certain plants is supported or inhibited by where they grow and in what substance. Soils support the growth of many kinds of plants, including those in our food supply. Understanding the properties of soil enables us to better understand the environment in which we live.

SCIENCE STANDARDS AND INDICATORS

Content Standard 2.3: Earth materials have varied physical properties which make them useful in different ways.

A21: Sort different soils by properties, such as particle size, color and composition.

A22: Relate the properties of different soils to their capacity to retain water and support the growth of certain plants.

SCIENCE INQUIRY: Scientific inquiry is a thoughtful and coordinated attempt to search out describe, explain and predict natural phenomena.

SCIENCE LITERACY: Science literacy includes speaking listening, presenting, interpreting, reading and writing about science.

SCIENCE NUMERACY: Mathematics provides useful tool for the description, analysis and presentation of scientific data and ideas.

EXPECTED PERFORMANCES

AINQ.2 Use senses and simple measuring tools to collect data

AINQ.4 Read, write and speak about observations of the natural world.

AINQ.9 Count, order and sort objects by their properties.

BIG IDEA

Soil is made of three different things and supports plant life in different ways.

LINKS TO OTHER STANDARDS

LANGUAGE ARTS

1.2.b. Interpret information that is implied in a text

1.3.d. Develop vocabulary through listening, speaking, reading and writing.

3.2.d. Research information from multiple sources for a specific purpose.

Key Vocabulary: soil, silt, clay, particles, properties, organic, textures, habitat, compost

ESSENTIAL KNOWLEDGE:

Soil is a mixture of pieces of rock (particles) living and once living things (humus), water, and air. The components of soil can be separated using devices and settlement tests.
There are different types of soil that vary from place to place. Soil properties can be observed and compared. Soils can be classified by properties such as color, particle size, and amount of organic material. Digging a deep hole shows that soils are often found in layers that have different colors and textures.
The size of the particles in soil gives the soil its texture. Soils can be classified by how they feel; sandy soils feel gritty, silt feels powdery, clay feels sticky and soils with small rocks feel rough and scratchy.
The broken rocks that make up soils can be tiny (silt and clay), medium (sand), or large (pebbles). Soils can be classified by the size of their particles.
A soil’s texture affects how it packs together; soils that pack together tightly hold less air and water than soils that stay loosely packed.
There are different types of soil that vary from place to place. Some soil types are suited for supporting the weight of buildings and highways; other types are suited for planting food crops or forest growth.
Many plants need soil to grow because it holds water and nutrients that are taken in by plant roots.
Soil is a habitat for many living things. Some organisms live in the soil, while others live on the soil. Underground organisms adapt the soil to their needs.
Plants that we eat grow in different soil types. Plant height, root length, number of leaves and flowers can all be affected by how much water air and other organic materials the soil holds.
To support the growth of different plants, people can change the properties of soil by adding nutrients (fertilizing), water (irrigating) or air (tilling).

CONCEPTS

Soil contains particles of different sizes.
Soil may contain animals, plants and their remains.
Over time, dead plants become part of soil.
Composting, especially with worms, is an effective way to recycle old plants and other discarded organic matter.
Sand, clay and humus are three basic components of soil.
Every soil component has unique properties that can be identified using simple tests.
Different soils absorb water at different rates.
Many factors, including soil, effect plant and root growth.

SKILLS:

· Performing simple tests to describe and identify soil components.

· Observing, recording, and organizing test results.

· Interpreting test results to draw conclusions about soil components.

· Reflecting on test results to predict how plants will grow in different so

· Assembling laboratory materials for soil experiments.

· Communicating results and ideas through writing, drawing and discussion.

· Applying previously learned concepts and skills to analyze unfamiliar soil samples.

ESSENTIAL QUESTIONS TO GUIDE INSTRUCTION AND ASSESSMENT:

What is soil?
What is soil made of?
What are the properties of different soils?
Why do different plants grow differently in different soils?
How does soil hold water?
How does soil support plant life?
What factors regarding soil affects plant and root growth?

MATERIALS AND SUPPLIES

STC Soils Kit

OBJECTIVES AND GOALS (as summarized from STC Kit, “Soils”)

LESSON ONE

What is in Soil?

Students share what they show about soil and what they want to find out.
Students discuss the difference between a prediction and an observation.
Students predict what they will find in a sample of garden soil.
Students observe soil with a hand lens.
Students compare and record observations of garden soil.

LESSON TWO

Where do dead plants go?

Students brainstorm where dead plants might go.
Students set up a five-week composting project using garden soil, worms and plant remains.
The class sets up a compost bag without worms for comparison (control).
Students predict what will happen to the organic matter in their compost bags.
Students describe and record observations of their organic matter.

LESSON THREE

Introducing Sand, Clay and Humus

Students discuss what they already know about sand, clay and humus.
Students examine sand, clay and humus with a hand lens.
Students touch, smell and listen to the three samples.
Students compare and discuss their observations.
Students record their observations through writing and drawing.

LESSON FOUR

When Soils Get Wet

Students describe the feel and appearance of moistened sand, clay and humus.
Students compare wet and dry samples, discussing similarities and differences.
Students discuss the results of rolling the moist samples between their fingers.
Students record their observations about moist samples.

LESSON FIVE

More About Wet Soils

Students conduct a smear test on sand, clay and humus.
Students record and discuss the results of the smear test.
Students observe and discuss changes in the clay balls made in the last lesson.
Students crush and moisten the dried clay balls and discuss the changes.
Students read about everyday uses for sand and clay.

LESSON SIX

How Quickly Do Soils Settle in Water?

Students predict what will happen when they separate soil and components by settling.
Students observe and describe the results of the settling test.
Through drawing, students record their test results.
Students compare and discuss the results of settling for the three samples.

LESSON SEVEN

More Settling a Few Days Later

Students observe further settling of sand, clay and humus.
Students discuss and record their observations of settled materials.
Students compare how the settled materials look now with how they looked during the last lesson.
Students observe the compost bags they set up in Lesson 2.

LESSON EIGHT

What is Your Mystery Mixture?

Students conduct soil tests on an unfamiliar mixture.
Students compare their test results with those from their previous tests on sand, clay and humus.
Students describe the properties of the new mixture.
Using their data, students infer which soil components their mystery mixture contains.
Students create a “mystery mixture” book with their record sheets.

LESSON NINE

Growing Plants in Different Soils

Students discuss their ideas about plant growth in different samples.
Students plant seeds in sand, clay or humus and their local soil.
Students begin a logbook of their plants’ progress.

LESSON TEN

Why Do Plants Have Roots in Soil?

Students brainstorm what the roots of a plant do.
Students plant seeds in clear tubes filled with sand, clay and humus.
Students monitor the growth of roots in each tube, watering them regularly.
Students observe and discuss changes in the materials in their compost bags.
Students read about earthworms and their connection to plant roots and soil.

LESSON ELEVEN

Can Soil Hold Water?

Students brainstorm a device to observe how water moves through humus.
Students compare the quantity of water added to humus with the quantity that filters through.
Students deduce where the missing water went.
Students discuss how rain soaks into the ground.
Students observe their planting cups and record plant growth.
Using a hand lens, students observe and compare root growth in sand, clay, and humus.

LESSON TWELVE

How Water Moves through Sand and Clay

Students pour water simultaneously over samples of sand and clay.
Students observe, compare, and record how water moves through the two samples.
Students brainstorm how their experiment resembles the effect of rain on soil.
Students observe their planting cups and record further plant growth.
Using a hand lens, students observe and compare root growth in sand, clay and humus.

LESSON THIRTEEN

Opening the Compost Bags

Students observe, discuss, and record changes that have occurred inside their compost bags.
Students compare their predictions and findings from earlier lessons to their observations today.
Students compare the results of composting with and without worms.
Students read about making compost outdoors.
Using a hand lens, students observe and discuss root growth in sand, clay and humus, comparing results among the three samples.

LESSON FOURTEEN

Exploring Your Local Soil

Students review previous soil tests and their results.
Students examine the local soil and predict which components it might contain.
Students run tests on the local soil.
Students discuss and record their findings.
Students compare their test results today with those from previous tests on sand, clay and humus.
Students observe their planting cups and record further plant growth.