Name:

Science Fair Paper Outline

  1. Thesis Statement

Identify the subtopics you will answer for the body of your paper. You may have less than or more than four to explore; this is just a template to start you focusing your research. You must have at least three good supporting paragraphs.

  1. Subtopic #1:

The composition of soil. What is soil? What is it made of? What are the definitions of the things that make up soil?

  1. Subtopic #2:

How soil is made. What factors influence how soil is made? What are the definitions/explanations of these factors?

  1. Subtopic #3:

The basic outline of soil. What does a typical picture of soil look like? What makes up the basic layers of soil? Is soil one layer or many?

  1. Subtopic #4:

Porosity. What is porosity? What is pore space? How much pore space is the best? What happens when there is too much pore space?

  1. Subtopic #5:

Soil and the World. Why is soil needed? How is soil used today?

  1. Body Paragraph #1

Subtopic (Topic Sentence)

On the whole, soil is composed of four basic materials: minerals, organic material, air and water.

  1. Research Information Based on the Subtopic.

The mineral component is further broken down into three main parts: sand, silt and clay. Soil may be characterized based on the properties of the materials from the underlying parent material.

Source: Soil-Net.com. “Soils: Advanced”

  1. Research Information Based on the Subtopic.

Sand is typically the largest particle found in soil. It is rough to the touch, has sharp edges and sand does not hold many nutrients. Silt is smaller than sand, but larger than clay. Silt feels smooth and powdery to the touch. Clay is the smallest of the three particles. Clay feels smooth to the touch when it is dry and very sticky when it is wet. Soils that have a high content of clay are considered to be heavy soils. “Clay also can hold a lot of nutrients, but doesn’t let air and water through it well.” (Urban Programs Resource Network-Case 2).

Source: University of Illinois Extension. Urban Programs Resource Network,

  1. Body Paragraph #2

Subtopic (Topic Sentence):

There are five factors that influence the type of soil that develops and they are: parent material, climate, living organisms, topography and time.

Research Information Based on the Subtopic.

The parent material refers to the primary material from which the soil is formed. Some of the materials can come from “bedrock, organic material, an old soil surface, or a deposit from water, wind, glaciers, volcanoes or material moving down a slope” (Soil Science Education Page).

Source: Trakhtenberg, Izolda. Soil Science Education, April 20, 2005.

  1. Research Information Based on the Subtopic.

Climate factors are shown in the weathering and erosion process. As the particles continue to be weathered and eroded, they become smaller and smaller. Weathering is when particles of rock are exposed to various chemical and mechanical processes that cause these particles to decompose. Some of these mechanical processes are exposure to heat, moisture, strong winds/storms, collisions with other hard surfaces, solar energy, etc.

Source: The Shawnee County Conservation District,

  1. Research Information Based on the Subtopic.

Organic material in soil comes from all the living organisms in or on the soil. The amount of water and nutrients, the decomposition of waste materials and how the materials are moved within the soil are all influenced by the organisms living in, on and around the soil such as humans, animals, and bacteria.

Source: Trakhtenberg, Izolda. Soil Science Education, April 20, 2005.

  1. Research Information Based on the Subtopic:

Where the soil is formed and its internal components are dependent upon the landscape surrounding the soil. For instance, soil formed at the bottom of a hill will be different from the soil formed at the side of a lakefront, which will be different from the soil formed in a backyard.

Source: Trakhtenberg, Izolda. Soil Science Education, April 20, 2005.

  1. Research Information Based on the Subtopic:

The amount of time that passes during the formation of the soil severely affects the internal composition of the soil. The longer the time that passes, the more compact the soil is so there is less space between the composition of the soil. The soil is more compact because there is more time for living organisms living in, on or around the soil to influence what the soil is composed of.

Source: Trakhtenberg, Izolda. Soil Science Education, April 20, 2005.

  1. Body Paragraph #3

Subtopic:

A standard picture of soil and a description of the layers.

  1. Research Information Based on the Subtopic.

“(O) The uppermost layer is called the organic horizon or the O horizon. This layer consists of detritus, leaf litter and other organic material lying on the surface of the soil. This layer is dark because of the decomposition that is occurring.

(A) Below is the A horizon or topsoil. Usually it is darker than lower layers, loose and crumbly with varying amounts of organic material. As water moves down through the topsoil, many soluble minerals and nutrients dissolve.

(B) The next layer is the B horizon or subsoil. Subsoils are usually lighter in color, dense and low in organic matter.

(C) Still deeper is the C horizon. It is a transition area between soil and parent material. Partially disintegrated parent material and mineral particles may be found in this horizon. At some point, the C horizon will give up to the final horizon, bedrock.” (

Source: The Shawnee County Conservation District,

  1. Research Information Based on the Subtopic.

Source: ______

Source: The Shawnee County Conservation District,

  1. Body Paragraph #4

Subtopic:

The space between particles is called pore space.

a.Research Information Based on the Subtopic.

Pore space determines the amount of water that a given volume of soil can hold. Porosity is the percentage of the total volume of soil that consists of pore space” (Hawaii Space Grant College).

Source: Francek, Mark. Resources for Earth Sciences and Geography Instruction. “ESC/BIO 334-Soil Science” January 2005.

b.Research Information Based on the Subtopic.

When pore space is very small, then water does not drain well throughout the soil which prevents proper aeration of the soil. Poor aeration and retention of water affects the quality of the soil. The pictures below show the ratios of air, water, mineral matter and organic material for the optimal type of soil and two very common compositions of soil.

Image courtesy of Profile Products, 2002, PROFILE Improves Any Soil Structure For Superior Performing Designs, 20 Jan. 2003.

Source: Hawaii Space Grant College. “Porosity” 1997.

c.Research Information Based on the Subtopic.

There is no identified optimal level of porosity, but it is important that the soil porosity allow enough water and air throughout the soil to maintain a level of nutrition that allows growth of living organisms in, on and around the soil.

Source: Hawaii Space Grant College. “Porosity” 1997.

  1. Body Paragraph #5

Subtopic:

Soil has many important functions within the current economy.

  1. Research Information Based on the Subtopic

The most important is to maintain the growth of agricultural crops. Agricultural growth is a main food source for the world, without proper growth many more people would starve. Soil is also important for the growth of natural vegetation such as forests, grasslands, etc. Without proper soil growth the many species that live in and depend upon these natural resources would perish and much of the world’s species diversity would cease to exist.

Source: Soil-Net.com. “Soils: Advanced”

  1. Research Information Based on the Subtopic

Another important function of soil is the “quality and distribution of the water supply. The soil coupled with the landscape and its vegetation is responsible for the distribution of all rainwater falling upon it. The nature of the topsoil will influence greatly whether the rainwater will run away across its surface or whether it will infiltrate to become stored in the soil.” (Soil-Net). If the water runs across the surface, then it can deposit into rivers, lakes, streams, etc. If the water is absorbed by the soil, then it will continue to support vegetation growth.

Source: Soil-Net.com. “Soils: Advanced”

  1. Research Information Based on the Subtopic

Soil also has an important function in the distribution of the pesticides placed upon land by farmers. How well the soil is aerated and how well water moves through the soil determines the concentration of pesticide per given area of soil. Soil is used in the foundations for many human inventions like roads, houses and buildings.

Source: Soil-Net.com. “Soils: Advanced”

  1. Research Information Based on the Subtopic

“Finally, soil has been recognized as having a key role in modifying and ameliorating the risks and effects of climate change. Soil organic matter is one of the major pools of carbon in the biosphere and is important both as a driver of climatic change and as a response variable to climate change, capable of acting both as a source and sink of carbon.” (Soil-Net).

Source: Soil-Net.com. “Soils: Advanced”