Or… Why did that bucket of water I spilled disappear into the ground. Learning Objective: I will be able to explain water movement in the ground Or… Why did that bucket of water I spilled disappear into the ground.

Success Criteria: 1) I can explain porosity. 2) I can explain the difference between sorted and unsorted. 3) I can explain permeability. 4) I can explain the relationship between porosity and permeability.

Porosity

Total volume of empty space Porosity = Total volume of empty space ÷ total volume of soil What materials would you need to calculate the porosity of a sample of soil? graduated cylinder water

Sorting Well sorted Well sorted soils: rounded particles similar in size not closely packed. They are the most porous. Unsorted soils: contain different sized particles and are more closely packed are less porous. Unsorted

Important – particle size alone may not affect the porosity of the soil. Soils with different particle size but with similar shape and packing can have the same porosity. 48% 48%

***Particle size alone does not determine porosity***

Which is more porous, a container of: round particles or angular particles tightly packed particles or loosely packed particles c. well-sorted particles or unsorted particles d. large beads or small beads

Check for understanding What is porosity and how does size and shape affect it?

Capillarity

Capillary Action in Soil The movement of a liquid along the surface of a solid caused by the attraction of molecules of the liquid to the molecules of the solid.

PERMEABILITY

A, because the particles are largest PERMEABILITY Which column would allow water to flow through fastest? Why? A, because the particles are largest

PERMEABILITY Particle Size

If you join sediment from A and D, PERMEABILITY If you join sediment from A and D, what would happen to the permeability? Why? Decreases because the small particles fill in the spaces

Which is more permeable? PERMEABILITY Which is more permeable? a. small particles or large particles b. frozen ground or unfrozen ground

Runoff Occurs when rainfall exceeds permeability. Or when a soil is saturated and cannot retain more water. Or when the slope of a soil’s surface is too great to allow infiltration.

RUNOFF AND STREAM DISCHARGE FACTORS AFFECTING RUNOFF AND STREAM DISCHARGE Which will result in greater runoff and stream discharge? an area that is vegetated or an area that is barren an area that has a steep slope or an area that is flat ground that is frozen or ground that is unfrozen d. ground that is saturated or ground that unsaturated

Summary: Success Criteria recap