1. *Take out your “Soils” web quest.*
Earth History: Day 23
Focus: Soil
12/11/17
Science Starter: Copy and answer. Which of these best explains how tectonic-plate movement causes the formation of mountain ranges?
*Sediment builds upward due to crushing forces of subducting plates.
*Convection currents in the mantle force two plates to collide.
*The plates separate, allowing the asthenosphere to push through and later cool.
*Pressure from colliding plates melts rock that later cools to form large boulders.
*Take out your “Soils” web quest.*

2. Plan for the Day Begin a lab on soil texture
Review key points from the web quest:
a. Components of soil
b. Factors affecting soil formation
c. Soil profile/horizons
d. Soil texture - how to interpret the Soil Texture Diagram
3. Practice activities – Soil texture
4. Begin “Weathering and Erosion” web quest.

3. Homework
Worksheet -“Different Soils for Different Climates”/”Soil Profile” – You will need to use your “Soils” web quest (soil layers/horizons) to complete this.

4. E.Q.
How are soils formed, and how are the basic components of soil used to determine soil texture?

5. The Jam Jar Soil Experiment (in a beaker)
Let’s do an experiment to identify the soil components of soil around the school. We’ll start today and finish tomorrow.
The Jam Jar Soil Experiment (in a beaker)

6. Take out your “Soils” web quest. Let’s discuss key items.

7. What are the components of soil?
Soil is composed of inorganic materials (weathered rock particles-sand, silt, clay), organic materials (decaying plant and animal matter and living organisms – bacteria), air and water.

8. Please add this to your “Soils” webquest
Humus – pronounced (HYOO mus)
The organic component of soil – decomposing leaves and animal matter and microorganisms
Why is the “humus” component of soil so critical?
It provides the nutrients that must be in the soil in order for plants and trees to grow. These, in turn, serve as food sources for animals (including us).

9. What factors affect soil formation?
Relief – slope of the land

10. What factors affect soil formation?
Climatic Factors
Climate is one of the most important factors affecting the formation of soil. Warmer temperatures and an abundance of water have a tendency to speed up the formation of soil; in some cases, rather dramatically. Whereas, cooler temperatures and less precipitation slow down soil formation.

11. What factors affect soil formation?
2. Organic Materials/Organisms In Soil
Organic matter makes up only a small fraction of the total materials in soil, yet it is extremely important. This organic material is made up of decomposing plants and animals, bacteria, fungi, and nutrients that have come from decomposed plants and animals. Living organisms chemically alter and mix the soils, and give a richness to the soil.

12. What factors affect soil formation?
3. Relief (Slope of the land-Topography) In areas that are flat, the soil typically tends to get deeper quicker than the surface erodes away. On steep slopes, erosion usually takes place quicker than the formation of new soil beneath. The result is that flat locations typically have a deeper, more mature soil layer than do locations with a steep slope.
4. Parent Material
This refers to the particles of weathered rock in the soil. It affects the mineral make-up of the soil.

13. What factors affect soil formation?
5. Time - Soil does not form overnight. In fact, soil formation can take thousands, and in some cases even millions of years. Thus, time is an obviously important factor in soil formation.

14. Soil-forming factors

15. Turn to your neighbor, and (without using your web quest), name the factors that affect soil formation.

16. Soil Profile -The soil profile is defined as a vertical section of the soil from the ground surface downwards to where the soil meets the underlying rock. Virtually all soil profiles are composed of a number of distinctive layers, termed horizons.

17. Soil Horizons -There are five soil horizons: O, A, E, B, and C
Soil Horizons -There are five soil horizons: O, A, E, B, and C. (R is used to denote bedrock.)
There is no set order for these horizons within a soil.  Some soil profiles have an A-C combination, some have an O-E-B, an O-A-B, or just an O.  Some profiles may have all the horizons, O-A-E-B-C-R.   In other words, all horizons may not be present at all locations. Why do you think this is so?

18. Porosity and Permeability

19. A substance can be porous but not permeable
A substance can be porous but not permeable. Permeability depends on whether or not the spaces between the pores are connected. Sand is too porous and permeable to hold water. Water drains through it quickly taking nutrients with it (leaching the soil) . But, sand particles in soil make it easy for air to circulate through the dirt, which helps to dry out moisture at the proper rate. Clay is incredibly absorbent (not as permeable), so it is excellent for retaining moisture that plants need. Silt basically acts like both sand and clay, holding some water while allowing the ground to aerate properly. A certain ratio of the 3 makes for good soil.

20. Soil Texture Diagram

21. The percentages of these 3 soil components (clay, silt, sand) are used to determine soil texture. If you know the percentage of any two, you can determine the 3rd, as well as the soil texture. This explains why some soils are more fertile than others. It also lets farmers/gard-eners know what they may need to do to enrich their soil.
Soil Texture Diagram

22. Soil texture The Ideal Soil Type: Loam
The type of soil that gardens and gardeners love is loamy soil. It contains a balance of all three soil materials—silt, sand and clay—plus humus. It has a higher pH and calcium levels because of its previous organic matter content.
Loam is dark in color and is mealy—soft, dry and crumbly—in your hands. It has a tight hold on water and plant food but it drains well, and air moves freely between soil particles down to the roots.

23. Let’s do a couple of practice activities analyzing a soil texture diagram.

25. Let’s begin a web quest on Weathering and Erosion.

26. Wrap-up: